docs/library: Remove "only" directive from all pyb module docs.

By virtue of its name, the pyb module would only be available on a pyboard
and so does not need to have conditional "only" directives throughout its
documentation.

These conditionals were added mostly in
cfcf47c064 in the initial development of the
cc3200 port, which had the pyb module before it switched to the machine
module.  And wipy only conditionals were removed from the pyb module
documentation in 4542643025, so there's no
need to retain any more conditionals.
This commit is contained in:
Damien George 2018-07-18 15:47:44 +10:00
parent 419eb86074
commit 805fd0cfe6
8 changed files with 966 additions and 1066 deletions

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@ -4,173 +4,164 @@
class ADC -- analog to digital conversion
=========================================
.. only:: port_pyboard
Usage::
Usage::
import pyb
import pyb
adc = pyb.ADC(pin) # create an analog object from a pin
val = adc.read() # read an analog value
adc = pyb.ADCAll(resolution) # create an ADCAll object
adc = pyb.ADCAll(resolution, mask) # create an ADCAll object for selected analog channels
val = adc.read_channel(channel) # read the given channel
val = adc.read_core_temp() # read MCU temperature
val = adc.read_core_vbat() # read MCU VBAT
val = adc.read_core_vref() # read MCU VREF
val = adc.read_vref() # read MCU supply voltage
adc = pyb.ADC(pin) # create an analog object from a pin
val = adc.read() # read an analog value
adc = pyb.ADCAll(resolution) # create an ADCAll object
adc = pyb.ADCAll(resolution, mask) # create an ADCAll object for selected analog channels
val = adc.read_channel(channel) # read the given channel
val = adc.read_core_temp() # read MCU temperature
val = adc.read_core_vbat() # read MCU VBAT
val = adc.read_core_vref() # read MCU VREF
val = adc.read_vref() # read MCU supply voltage
Constructors
------------
.. class:: pyb.ADC(pin)
.. only:: port_pyboard
.. class:: pyb.ADC(pin)
Create an ADC object associated with the given pin.
This allows you to then read analog values on that pin.
Create an ADC object associated with the given pin.
This allows you to then read analog values on that pin.
Methods
-------
.. only:: port_pyboard
.. method:: ADC.read()
.. method:: ADC.read()
Read the value on the analog pin and return it. The returned value
will be between 0 and 4095.
Read the value on the analog pin and return it. The returned value
will be between 0 and 4095.
.. method:: ADC.read_timed(buf, timer)
.. method:: ADC.read_timed(buf, timer)
Read analog values into ``buf`` at a rate set by the ``timer`` object.
Read analog values into ``buf`` at a rate set by the ``timer`` object.
``buf`` can be bytearray or array.array for example. The ADC values have
12-bit resolution and are stored directly into ``buf`` if its element size is
16 bits or greater. If ``buf`` has only 8-bit elements (eg a bytearray) then
the sample resolution will be reduced to 8 bits.
``buf`` can be bytearray or array.array for example. The ADC values have
12-bit resolution and are stored directly into ``buf`` if its element size is
16 bits or greater. If ``buf`` has only 8-bit elements (eg a bytearray) then
the sample resolution will be reduced to 8 bits.
``timer`` should be a Timer object, and a sample is read each time the timer
triggers. The timer must already be initialised and running at the desired
sampling frequency.
``timer`` should be a Timer object, and a sample is read each time the timer
triggers. The timer must already be initialised and running at the desired
sampling frequency.
To support previous behaviour of this function, ``timer`` can also be an
integer which specifies the frequency (in Hz) to sample at. In this case
Timer(6) will be automatically configured to run at the given frequency.
To support previous behaviour of this function, ``timer`` can also be an
integer which specifies the frequency (in Hz) to sample at. In this case
Timer(6) will be automatically configured to run at the given frequency.
Example using a Timer object (preferred way)::
Example using a Timer object (preferred way)::
adc = pyb.ADC(pyb.Pin.board.X19) # create an ADC on pin X19
tim = pyb.Timer(6, freq=10) # create a timer running at 10Hz
buf = bytearray(100) # creat a buffer to store the samples
adc.read_timed(buf, tim) # sample 100 values, taking 10s
adc = pyb.ADC(pyb.Pin.board.X19) # create an ADC on pin X19
tim = pyb.Timer(6, freq=10) # create a timer running at 10Hz
buf = bytearray(100) # creat a buffer to store the samples
adc.read_timed(buf, tim) # sample 100 values, taking 10s
Example using an integer for the frequency::
Example using an integer for the frequency::
adc = pyb.ADC(pyb.Pin.board.X19) # create an ADC on pin X19
buf = bytearray(100) # create a buffer of 100 bytes
adc.read_timed(buf, 10) # read analog values into buf at 10Hz
# this will take 10 seconds to finish
for val in buf: # loop over all values
print(val) # print the value out
adc = pyb.ADC(pyb.Pin.board.X19) # create an ADC on pin X19
buf = bytearray(100) # create a buffer of 100 bytes
adc.read_timed(buf, 10) # read analog values into buf at 10Hz
# this will take 10 seconds to finish
for val in buf: # loop over all values
print(val) # print the value out
This function does not allocate any heap memory. It has blocking behaviour:
it does not return to the calling program until the buffer is full.
This function does not allocate any heap memory. It has blocking behaviour:
it does not return to the calling program until the buffer is full.
.. method:: ADC.read_timed_multi((adcx, adcy, ...), (bufx, bufy, ...), timer)
.. method:: ADC.read_timed_multi((adcx, adcy, ...), (bufx, bufy, ...), timer)
This is a static method. It can be used to extract relative timing or
phase data from multiple ADC's.
This is a static method. It can be used to extract relative timing or
phase data from multiple ADC's.
It reads analog values from multiple ADC's into buffers at a rate set by
the *timer* object. Each time the timer triggers a sample is rapidly
read from each ADC in turn.
It reads analog values from multiple ADC's into buffers at a rate set by
the *timer* object. Each time the timer triggers a sample is rapidly
read from each ADC in turn.
ADC and buffer instances are passed in tuples with each ADC having an
associated buffer. All buffers must be of the same type and length and
the number of buffers must equal the number of ADC's.
ADC and buffer instances are passed in tuples with each ADC having an
associated buffer. All buffers must be of the same type and length and
the number of buffers must equal the number of ADC's.
Buffers can be ``bytearray`` or ``array.array`` for example. The ADC values
have 12-bit resolution and are stored directly into the buffer if its element
size is 16 bits or greater. If buffers have only 8-bit elements (eg a
``bytearray``) then the sample resolution will be reduced to 8 bits.
Buffers can be ``bytearray`` or ``array.array`` for example. The ADC values
have 12-bit resolution and are stored directly into the buffer if its element
size is 16 bits or greater. If buffers have only 8-bit elements (eg a
``bytearray``) then the sample resolution will be reduced to 8 bits.
*timer* must be a Timer object. The timer must already be initialised
and running at the desired sampling frequency.
*timer* must be a Timer object. The timer must already be initialised
and running at the desired sampling frequency.
Example reading 3 ADC's::
Example reading 3 ADC's::
adc0 = pyb.ADC(pyb.Pin.board.X1) # Create ADC's
adc1 = pyb.ADC(pyb.Pin.board.X2)
adc2 = pyb.ADC(pyb.Pin.board.X3)
tim = pyb.Timer(8, freq=100) # Create timer
rx0 = array.array('H', (0 for i in range(100))) # ADC buffers of
rx1 = array.array('H', (0 for i in range(100))) # 100 16-bit words
rx2 = array.array('H', (0 for i in range(100)))
# read analog values into buffers at 100Hz (takes one second)
pyb.ADC.read_timed_multi((adc0, adc1, adc2), (rx0, rx1, rx2), tim)
for n in range(len(rx0)):
print(rx0[n], rx1[n], rx2[n])
adc0 = pyb.ADC(pyb.Pin.board.X1) # Create ADC's
adc1 = pyb.ADC(pyb.Pin.board.X2)
adc2 = pyb.ADC(pyb.Pin.board.X3)
tim = pyb.Timer(8, freq=100) # Create timer
rx0 = array.array('H', (0 for i in range(100))) # ADC buffers of
rx1 = array.array('H', (0 for i in range(100))) # 100 16-bit words
rx2 = array.array('H', (0 for i in range(100)))
# read analog values into buffers at 100Hz (takes one second)
pyb.ADC.read_timed_multi((adc0, adc1, adc2), (rx0, rx1, rx2), tim)
for n in range(len(rx0)):
print(rx0[n], rx1[n], rx2[n])
This function does not allocate any heap memory. It has blocking behaviour:
it does not return to the calling program until the buffers are full.
This function does not allocate any heap memory. It has blocking behaviour:
it does not return to the calling program until the buffers are full.
The function returns ``True`` if all samples were acquired with correct
timing. At high sample rates the time taken to acquire a set of samples
can exceed the timer period. In this case the function returns ``False``,
indicating a loss of precision in the sample interval. In extreme cases
samples may be missed.
The function returns ``True`` if all samples were acquired with correct
timing. At high sample rates the time taken to acquire a set of samples
can exceed the timer period. In this case the function returns ``False``,
indicating a loss of precision in the sample interval. In extreme cases
samples may be missed.
The maximum rate depends on factors including the data width and the
number of ADC's being read. In testing two ADC's were sampled at a timer
rate of 210kHz without overrun. Samples were missed at 215kHz. For three
ADC's the limit is around 140kHz, and for four it is around 110kHz.
At high sample rates disabling interrupts for the duration can reduce the
risk of sporadic data loss.
The maximum rate depends on factors including the data width and the
number of ADC's being read. In testing two ADC's were sampled at a timer
rate of 210kHz without overrun. Samples were missed at 215kHz. For three
ADC's the limit is around 140kHz, and for four it is around 110kHz.
At high sample rates disabling interrupts for the duration can reduce the
risk of sporadic data loss.
The ADCAll Object
-----------------
.. only:: port_pyboard
Instantiating this changes all masked ADC pins to analog inputs. The preprocessed MCU temperature,
VREF and VBAT data can be accessed on ADC channels 16, 17 and 18 respectively.
Appropriate scaling is handled according to reference voltage used (usually 3.3V).
The temperature sensor on the chip is factory calibrated and allows to read the die temperature
to +/- 1 degree centigrade. Although this sounds pretty accurate, don't forget that the MCU's internal
temperature is measured. Depending on processing loads and I/O subsystems active the die temperature
may easily be tens of degrees above ambient temperature. On the other hand a pyboard woken up after a
long standby period will show correct ambient temperature within limits mentioned above.
Instantiating this changes all masked ADC pins to analog inputs. The preprocessed MCU temperature,
VREF and VBAT data can be accessed on ADC channels 16, 17 and 18 respectively.
Appropriate scaling is handled according to reference voltage used (usually 3.3V).
The temperature sensor on the chip is factory calibrated and allows to read the die temperature
to +/- 1 degree centigrade. Although this sounds pretty accurate, don't forget that the MCU's internal
temperature is measured. Depending on processing loads and I/O subsystems active the die temperature
may easily be tens of degrees above ambient temperature. On the other hand a pyboard woken up after a
long standby period will show correct ambient temperature within limits mentioned above.
The ``ADCAll`` ``read_core_vbat()``, ``read_vref()`` and ``read_core_vref()`` methods read
the backup battery voltage, reference voltage and the (1.21V nominal) reference voltage using the
actual supply as a reference. All results are floating point numbers giving direct voltage values.
The ``ADCAll`` ``read_core_vbat()``, ``read_vref()`` and ``read_core_vref()`` methods read
the backup battery voltage, reference voltage and the (1.21V nominal) reference voltage using the
actual supply as a reference. All results are floating point numbers giving direct voltage values.
``read_core_vbat()`` returns the voltage of the backup battery. This voltage is also adjusted according
to the actual supply voltage. To avoid analog input overload the battery voltage is measured
via a voltage divider and scaled according to the divider value. To prevent excessive loads
to the backup battery, the voltage divider is only active during ADC conversion.
``read_core_vbat()`` returns the voltage of the backup battery. This voltage is also adjusted according
to the actual supply voltage. To avoid analog input overload the battery voltage is measured
via a voltage divider and scaled according to the divider value. To prevent excessive loads
to the backup battery, the voltage divider is only active during ADC conversion.
``read_vref()`` is evaluated by measuring the internal voltage reference and backscale it using
factory calibration value of the internal voltage reference. In most cases the reading would be close
to 3.3V. If the pyboard is operated from a battery, the supply voltage may drop to values below 3.3V.
The pyboard will still operate fine as long as the operating conditions are met. With proper settings
of MCU clock, flash access speed and programming mode it is possible to run the pyboard down to
2 V and still get useful ADC conversion.
``read_vref()`` is evaluated by measuring the internal voltage reference and backscale it using
factory calibration value of the internal voltage reference. In most cases the reading would be close
to 3.3V. If the pyboard is operated from a battery, the supply voltage may drop to values below 3.3V.
The pyboard will still operate fine as long as the operating conditions are met. With proper settings
of MCU clock, flash access speed and programming mode it is possible to run the pyboard down to
2 V and still get useful ADC conversion.
It is very important to make sure analog input voltages never exceed actual supply voltage.
It is very important to make sure analog input voltages never exceed actual supply voltage.
Other analog input channels (0..15) will return unscaled integer values according to the selected
precision.
Other analog input channels (0..15) will return unscaled integer values according to the selected
precision.
To avoid unwanted activation of analog inputs (channel 0..15) a second parameter can be specified.
This parameter is a binary pattern where each requested analog input has the corresponding bit set.
The default value is 0xffffffff which means all analog inputs are active. If just the internal
channels (16..18) are required, the mask value should be 0x70000.
To avoid unwanted activation of analog inputs (channel 0..15) a second parameter can be specified.
This parameter is a binary pattern where each requested analog input has the corresponding bit set.
The default value is 0xffffffff which means all analog inputs are active. If just the internal
channels (16..18) are required, the mask value should be 0x70000.
Example::
Example::
adcall = pyb.ADCAll(12, 0x70000) # 12 bit resolution, internal channels
temp = adcall.read_core_temp()
adcall = pyb.ADCAll(12, 0x70000) # 12 bit resolution, internal channels
temp = adcall.read_core_temp()

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@ -10,78 +10,72 @@ level it consists of 2 wires: SCL and SDA, the clock and data lines respectively
I2C objects are created attached to a specific bus. They can be initialised
when created, or initialised later on.
.. only:: port_pyboard
Example::
Example::
from pyb import I2C
from pyb import I2C
i2c = I2C(1) # create on bus 1
i2c = I2C(1, I2C.MASTER) # create and init as a master
i2c.init(I2C.MASTER, baudrate=20000) # init as a master
i2c.init(I2C.SLAVE, addr=0x42) # init as a slave with given address
i2c.deinit() # turn off the peripheral
i2c = I2C(1) # create on bus 1
i2c = I2C(1, I2C.MASTER) # create and init as a master
i2c.init(I2C.MASTER, baudrate=20000) # init as a master
i2c.init(I2C.SLAVE, addr=0x42) # init as a slave with given address
i2c.deinit() # turn off the peripheral
Printing the i2c object gives you information about its configuration.
.. only:: port_pyboard
The basic methods are send and recv::
The basic methods are send and recv::
i2c.send('abc') # send 3 bytes
i2c.send(0x42) # send a single byte, given by the number
data = i2c.recv(3) # receive 3 bytes
i2c.send('abc') # send 3 bytes
i2c.send(0x42) # send a single byte, given by the number
data = i2c.recv(3) # receive 3 bytes
To receive inplace, first create a bytearray::
To receive inplace, first create a bytearray::
data = bytearray(3) # create a buffer
i2c.recv(data) # receive 3 bytes, writing them into data
data = bytearray(3) # create a buffer
i2c.recv(data) # receive 3 bytes, writing them into data
You can specify a timeout (in ms)::
You can specify a timeout (in ms)::
i2c.send(b'123', timeout=2000) # timeout after 2 seconds
i2c.send(b'123', timeout=2000) # timeout after 2 seconds
A master must specify the recipient's address::
A master must specify the recipient's address::
i2c.init(I2C.MASTER)
i2c.send('123', 0x42) # send 3 bytes to slave with address 0x42
i2c.send(b'456', addr=0x42) # keyword for address
i2c.init(I2C.MASTER)
i2c.send('123', 0x42) # send 3 bytes to slave with address 0x42
i2c.send(b'456', addr=0x42) # keyword for address
Master also has other methods::
Master also has other methods::
i2c.is_ready(0x42) # check if slave 0x42 is ready
i2c.scan() # scan for slaves on the bus, returning
# a list of valid addresses
i2c.mem_read(3, 0x42, 2) # read 3 bytes from memory of slave 0x42,
# starting at address 2 in the slave
i2c.mem_write('abc', 0x42, 2, timeout=1000) # write 'abc' (3 bytes) to memory of slave 0x42
# starting at address 2 in the slave, timeout after 1 second
i2c.is_ready(0x42) # check if slave 0x42 is ready
i2c.scan() # scan for slaves on the bus, returning
# a list of valid addresses
i2c.mem_read(3, 0x42, 2) # read 3 bytes from memory of slave 0x42,
# starting at address 2 in the slave
i2c.mem_write('abc', 0x42, 2, timeout=1000) # write 'abc' (3 bytes) to memory of slave 0x42
# starting at address 2 in the slave, timeout after 1 second
Constructors
------------
.. only:: port_pyboard
.. class:: pyb.I2C(bus, ...)
.. class:: pyb.I2C(bus, ...)
Construct an I2C object on the given bus. ``bus`` can be 1 or 2, 'X' or
'Y'. With no additional parameters, the I2C object is created but not
initialised (it has the settings from the last initialisation of
the bus, if any). If extra arguments are given, the bus is initialised.
See ``init`` for parameters of initialisation.
Construct an I2C object on the given bus. ``bus`` can be 1 or 2, 'X' or
'Y'. With no additional parameters, the I2C object is created but not
initialised (it has the settings from the last initialisation of
the bus, if any). If extra arguments are given, the bus is initialised.
See ``init`` for parameters of initialisation.
The physical pins of the I2C busses on Pyboards V1.0 and V1.1 are:
The physical pins of the I2C busses on Pyboards V1.0 and V1.1 are:
- ``I2C(1)`` is on the X position: ``(SCL, SDA) = (X9, X10) = (PB6, PB7)``
- ``I2C(2)`` is on the Y position: ``(SCL, SDA) = (Y9, Y10) = (PB10, PB11)``
- ``I2C(1)`` is on the X position: ``(SCL, SDA) = (X9, X10) = (PB6, PB7)``
- ``I2C(2)`` is on the Y position: ``(SCL, SDA) = (Y9, Y10) = (PB10, PB11)``
On the Pyboard Lite:
- ``I2C(1)`` is on the X position: ``(SCL, SDA) = (X9, X10) = (PB6, PB7)``
- ``I2C(3)`` is on the Y position: ``(SCL, SDA) = (Y9, Y10) = (PA8, PB8)``
Calling the constructor with 'X' or 'Y' enables portability between Pyboard
types.
On the Pyboard Lite:
- ``I2C(1)`` is on the X position: ``(SCL, SDA) = (X9, X10) = (PB6, PB7)``
- ``I2C(3)`` is on the Y position: ``(SCL, SDA) = (Y9, Y10) = (PA8, PB8)``
Calling the constructor with 'X' or 'Y' enables portability between Pyboard
types.
Methods
-------
@ -90,71 +84,69 @@ Methods
Turn off the I2C bus.
.. only:: port_pyboard
.. method:: I2C.init(mode, \*, addr=0x12, baudrate=400000, gencall=False, dma=False)
.. method:: I2C.init(mode, \*, addr=0x12, baudrate=400000, gencall=False, dma=False)
Initialise the I2C bus with the given parameters:
Initialise the I2C bus with the given parameters:
- ``mode`` must be either ``I2C.MASTER`` or ``I2C.SLAVE``
- ``addr`` is the 7-bit address (only sensible for a slave)
- ``baudrate`` is the SCL clock rate (only sensible for a master)
- ``gencall`` is whether to support general call mode
- ``dma`` is whether to allow the use of DMA for the I2C transfers (note
that DMA transfers have more precise timing but currently do not handle bus
errors properly)
- ``mode`` must be either ``I2C.MASTER`` or ``I2C.SLAVE``
- ``addr`` is the 7-bit address (only sensible for a slave)
- ``baudrate`` is the SCL clock rate (only sensible for a master)
- ``gencall`` is whether to support general call mode
- ``dma`` is whether to allow the use of DMA for the I2C transfers (note
that DMA transfers have more precise timing but currently do not handle bus
errors properly)
.. method:: I2C.is_ready(addr)
.. method:: I2C.is_ready(addr)
Check if an I2C device responds to the given address. Only valid when in master mode.
Check if an I2C device responds to the given address. Only valid when in master mode.
.. method:: I2C.mem_read(data, addr, memaddr, \*, timeout=5000, addr_size=8)
.. method:: I2C.mem_read(data, addr, memaddr, \*, timeout=5000, addr_size=8)
Read from the memory of an I2C device:
Read from the memory of an I2C device:
- ``data`` can be an integer (number of bytes to read) or a buffer to read into
- ``addr`` is the I2C device address
- ``memaddr`` is the memory location within the I2C device
- ``timeout`` is the timeout in milliseconds to wait for the read
- ``addr_size`` selects width of memaddr: 8 or 16 bits
- ``data`` can be an integer (number of bytes to read) or a buffer to read into
- ``addr`` is the I2C device address
- ``memaddr`` is the memory location within the I2C device
- ``timeout`` is the timeout in milliseconds to wait for the read
- ``addr_size`` selects width of memaddr: 8 or 16 bits
Returns the read data.
This is only valid in master mode.
Returns the read data.
This is only valid in master mode.
.. method:: I2C.mem_write(data, addr, memaddr, \*, timeout=5000, addr_size=8)
.. method:: I2C.mem_write(data, addr, memaddr, \*, timeout=5000, addr_size=8)
Write to the memory of an I2C device:
Write to the memory of an I2C device:
- ``data`` can be an integer or a buffer to write from
- ``addr`` is the I2C device address
- ``memaddr`` is the memory location within the I2C device
- ``timeout`` is the timeout in milliseconds to wait for the write
- ``addr_size`` selects width of memaddr: 8 or 16 bits
- ``data`` can be an integer or a buffer to write from
- ``addr`` is the I2C device address
- ``memaddr`` is the memory location within the I2C device
- ``timeout`` is the timeout in milliseconds to wait for the write
- ``addr_size`` selects width of memaddr: 8 or 16 bits
Returns ``None``.
This is only valid in master mode.
Returns ``None``.
This is only valid in master mode.
.. method:: I2C.recv(recv, addr=0x00, \*, timeout=5000)
.. method:: I2C.recv(recv, addr=0x00, \*, timeout=5000)
Receive data on the bus:
Receive data on the bus:
- ``recv`` can be an integer, which is the number of bytes to receive,
or a mutable buffer, which will be filled with received bytes
- ``addr`` is the address to receive from (only required in master mode)
- ``timeout`` is the timeout in milliseconds to wait for the receive
- ``recv`` can be an integer, which is the number of bytes to receive,
or a mutable buffer, which will be filled with received bytes
- ``addr`` is the address to receive from (only required in master mode)
- ``timeout`` is the timeout in milliseconds to wait for the receive
Return value: if ``recv`` is an integer then a new buffer of the bytes received,
otherwise the same buffer that was passed in to ``recv``.
Return value: if ``recv`` is an integer then a new buffer of the bytes received,
otherwise the same buffer that was passed in to ``recv``.
.. method:: I2C.send(send, addr=0x00, \*, timeout=5000)
.. method:: I2C.send(send, addr=0x00, \*, timeout=5000)
Send data on the bus:
Send data on the bus:
- ``send`` is the data to send (an integer to send, or a buffer object)
- ``addr`` is the address to send to (only required in master mode)
- ``timeout`` is the timeout in milliseconds to wait for the send
- ``send`` is the data to send (an integer to send, or a buffer object)
- ``addr`` is the address to send to (only required in master mode)
- ``timeout`` is the timeout in milliseconds to wait for the send
Return value: ``None``.
Return value: ``None``.
.. method:: I2C.scan()
@ -168,8 +160,6 @@ Constants
for initialising the bus to master mode
.. only:: port_pyboard
.. data:: I2C.SLAVE
.. data:: I2C.SLAVE
for initialising the bus to slave mode
for initialising the bus to slave mode

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@ -10,68 +10,66 @@ digital logic level. For analog control of a pin, see the ADC class.
Usage Model:
.. only:: port_pyboard
All Board Pins are predefined as pyb.Pin.board.Name::
All Board Pins are predefined as pyb.Pin.board.Name::
x1_pin = pyb.Pin.board.X1
g = pyb.Pin(pyb.Pin.board.X1, pyb.Pin.IN)
CPU pins which correspond to the board pins are available
as ``pyb.cpu.Name``. For the CPU pins, the names are the port letter
followed by the pin number. On the PYBv1.0, ``pyb.Pin.board.X1`` and
``pyb.Pin.cpu.A0`` are the same pin.
You can also use strings::
g = pyb.Pin('X1', pyb.Pin.OUT_PP)
Users can add their own names::
MyMapperDict = { 'LeftMotorDir' : pyb.Pin.cpu.C12 }
pyb.Pin.dict(MyMapperDict)
g = pyb.Pin("LeftMotorDir", pyb.Pin.OUT_OD)
and can query mappings::
pin = pyb.Pin("LeftMotorDir")
Users can also add their own mapping function::
def MyMapper(pin_name):
if pin_name == "LeftMotorDir":
return pyb.Pin.cpu.A0
pyb.Pin.mapper(MyMapper)
So, if you were to call: ``pyb.Pin("LeftMotorDir", pyb.Pin.OUT_PP)``
then ``"LeftMotorDir"`` is passed directly to the mapper function.
To summarise, the following order determines how things get mapped into
an ordinal pin number:
1. Directly specify a pin object
2. User supplied mapping function
3. User supplied mapping (object must be usable as a dictionary key)
4. Supply a string which matches a board pin
5. Supply a string which matches a CPU port/pin
You can set ``pyb.Pin.debug(True)`` to get some debug information about
how a particular object gets mapped to a pin.
When a pin has the ``Pin.PULL_UP`` or ``Pin.PULL_DOWN`` pull-mode enabled,
that pin has an effective 40k Ohm resistor pulling it to 3V3 or GND
respectively (except pin Y5 which has 11k Ohm resistors).
x1_pin = pyb.Pin.board.X1
Now every time a falling edge is seen on the gpio pin, the callback will be
executed. Caution: mechanical push buttons have "bounce" and pushing or
releasing a switch will often generate multiple edges.
See: http://www.eng.utah.edu/~cs5780/debouncing.pdf for a detailed
explanation, along with various techniques for debouncing.
g = pyb.Pin(pyb.Pin.board.X1, pyb.Pin.IN)
All pin objects go through the pin mapper to come up with one of the
gpio pins.
CPU pins which correspond to the board pins are available
as ``pyb.cpu.Name``. For the CPU pins, the names are the port letter
followed by the pin number. On the PYBv1.0, ``pyb.Pin.board.X1`` and
``pyb.Pin.cpu.A0`` are the same pin.
You can also use strings::
g = pyb.Pin('X1', pyb.Pin.OUT_PP)
Users can add their own names::
MyMapperDict = { 'LeftMotorDir' : pyb.Pin.cpu.C12 }
pyb.Pin.dict(MyMapperDict)
g = pyb.Pin("LeftMotorDir", pyb.Pin.OUT_OD)
and can query mappings::
pin = pyb.Pin("LeftMotorDir")
Users can also add their own mapping function::
def MyMapper(pin_name):
if pin_name == "LeftMotorDir":
return pyb.Pin.cpu.A0
pyb.Pin.mapper(MyMapper)
So, if you were to call: ``pyb.Pin("LeftMotorDir", pyb.Pin.OUT_PP)``
then ``"LeftMotorDir"`` is passed directly to the mapper function.
To summarise, the following order determines how things get mapped into
an ordinal pin number:
1. Directly specify a pin object
2. User supplied mapping function
3. User supplied mapping (object must be usable as a dictionary key)
4. Supply a string which matches a board pin
5. Supply a string which matches a CPU port/pin
You can set ``pyb.Pin.debug(True)`` to get some debug information about
how a particular object gets mapped to a pin.
When a pin has the ``Pin.PULL_UP`` or ``Pin.PULL_DOWN`` pull-mode enabled,
that pin has an effective 40k Ohm resistor pulling it to 3V3 or GND
respectively (except pin Y5 which has 11k Ohm resistors).
Now every time a falling edge is seen on the gpio pin, the callback will be
executed. Caution: mechanical push buttons have "bounce" and pushing or
releasing a switch will often generate multiple edges.
See: http://www.eng.utah.edu/~cs5780/debouncing.pdf for a detailed
explanation, along with various techniques for debouncing.
All pin objects go through the pin mapper to come up with one of the
gpio pins.
Constructors
------------
@ -81,52 +79,48 @@ Constructors
Create a new Pin object associated with the id. If additional arguments are given,
they are used to initialise the pin. See :meth:`pin.init`.
.. only:: port_pyboard
Class methods
-------------
Class methods
-------------
.. classmethod:: Pin.debug([state])
.. classmethod:: Pin.debug([state])
Get or set the debugging state (``True`` or ``False`` for on or off).
.. classmethod:: Pin.dict([dict])
Get or set the pin mapper dictionary.
.. classmethod:: Pin.mapper([fun])
Get or set the pin mapper function.
Get or set the debugging state (``True`` or ``False`` for on or off).
.. classmethod:: Pin.dict([dict])
Get or set the pin mapper dictionary.
.. classmethod:: Pin.mapper([fun])
Get or set the pin mapper function.
Methods
-------
.. only:: port_pyboard
.. method:: Pin.init(mode, pull=Pin.PULL_NONE, af=-1)
.. method:: Pin.init(mode, pull=Pin.PULL_NONE, af=-1)
Initialise the pin:
- ``mode`` can be one of:
Initialise the pin:
- ``Pin.IN`` - configure the pin for input;
- ``Pin.OUT_PP`` - configure the pin for output, with push-pull control;
- ``Pin.OUT_OD`` - configure the pin for output, with open-drain control;
- ``Pin.AF_PP`` - configure the pin for alternate function, pull-pull;
- ``Pin.AF_OD`` - configure the pin for alternate function, open-drain;
- ``Pin.ANALOG`` - configure the pin for analog.
- ``mode`` can be one of:
- ``pull`` can be one of:
- ``Pin.IN`` - configure the pin for input;
- ``Pin.OUT_PP`` - configure the pin for output, with push-pull control;
- ``Pin.OUT_OD`` - configure the pin for output, with open-drain control;
- ``Pin.AF_PP`` - configure the pin for alternate function, pull-pull;
- ``Pin.AF_OD`` - configure the pin for alternate function, open-drain;
- ``Pin.ANALOG`` - configure the pin for analog.
- ``Pin.PULL_NONE`` - no pull up or down resistors;
- ``Pin.PULL_UP`` - enable the pull-up resistor;
- ``Pin.PULL_DOWN`` - enable the pull-down resistor.
- ``pull`` can be one of:
- when mode is ``Pin.AF_PP`` or ``Pin.AF_OD``, then af can be the index or name
of one of the alternate functions associated with a pin.
Returns: ``None``.
- ``Pin.PULL_NONE`` - no pull up or down resistors;
- ``Pin.PULL_UP`` - enable the pull-up resistor;
- ``Pin.PULL_DOWN`` - enable the pull-down resistor.
- when mode is ``Pin.AF_PP`` or ``Pin.AF_OD``, then af can be the index or name
of one of the alternate functions associated with a pin.
Returns: ``None``.
.. method:: Pin.value([value])
@ -137,47 +131,45 @@ Methods
anything that converts to a boolean. If it converts to ``True``, the pin
is set high, otherwise it is set low.
.. only:: port_pyboard
.. method:: Pin.__str__()
.. method:: Pin.__str__()
Return a string describing the pin object.
.. method:: Pin.af()
Returns the currently configured alternate-function of the pin. The
integer returned will match one of the allowed constants for the af
argument to the init function.
Return a string describing the pin object.
.. method:: Pin.af_list()
.. method:: Pin.af()
Returns an array of alternate functions available for this pin.
.. method:: Pin.gpio()
Returns the base address of the GPIO block associated with this pin.
.. method:: Pin.mode()
Returns the currently configured mode of the pin. The integer returned
will match one of the allowed constants for the mode argument to the init
function.
.. method:: Pin.name()
Returns the currently configured alternate-function of the pin. The
integer returned will match one of the allowed constants for the af
argument to the init function.
Get the pin name.
.. method:: Pin.af_list()
.. method:: Pin.names()
Returns the cpu and board names for this pin.
.. method:: Pin.pin()
Get the pin number.
.. method:: Pin.port()
Get the pin port.
Returns an array of alternate functions available for this pin.
.. method:: Pin.gpio()
Returns the base address of the GPIO block associated with this pin.
.. method:: Pin.mode()
Returns the currently configured mode of the pin. The integer returned
will match one of the allowed constants for the mode argument to the init
function.
.. method:: Pin.name()
Get the pin name.
.. method:: Pin.names()
Returns the cpu and board names for this pin.
.. method:: Pin.pin()
Get the pin number.
.. method:: Pin.port()
Get the pin port.
.. method:: Pin.pull()
@ -188,93 +180,89 @@ Methods
Constants
---------
.. only:: port_pyboard
.. data:: Pin.AF_OD
.. data:: Pin.AF_OD
initialise the pin to alternate-function mode with an open-drain drive
.. data:: Pin.AF_PP
initialise the pin to alternate-function mode with a push-pull drive
.. data:: Pin.ANALOG
initialise the pin to analog mode
.. data:: Pin.IN
initialise the pin to input mode
.. data:: Pin.OUT_OD
initialise the pin to output mode with an open-drain drive
.. data:: Pin.OUT_PP
initialise the pin to output mode with a push-pull drive
.. data:: Pin.PULL_DOWN
enable the pull-down resistor on the pin
.. data:: Pin.PULL_NONE
don't enable any pull up or down resistors on the pin
.. data:: Pin.PULL_UP
enable the pull-up resistor on the pin
initialise the pin to alternate-function mode with an open-drain drive
.. only:: port_pyboard
.. data:: Pin.AF_PP
class PinAF -- Pin Alternate Functions
======================================
A Pin represents a physical pin on the microprocessor. Each pin
can have a variety of functions (GPIO, I2C SDA, etc). Each PinAF
object represents a particular function for a pin.
Usage Model::
x3 = pyb.Pin.board.X3
x3_af = x3.af_list()
x3_af will now contain an array of PinAF objects which are available on
pin X3.
For the pyboard, x3_af would contain:
[Pin.AF1_TIM2, Pin.AF2_TIM5, Pin.AF3_TIM9, Pin.AF7_USART2]
Normally, each peripheral would configure the af automatically, but sometimes
the same function is available on multiple pins, and having more control
is desired.
To configure X3 to expose TIM2_CH3, you could use::
pin = pyb.Pin(pyb.Pin.board.X3, mode=pyb.Pin.AF_PP, af=pyb.Pin.AF1_TIM2)
or::
pin = pyb.Pin(pyb.Pin.board.X3, mode=pyb.Pin.AF_PP, af=1)
initialise the pin to alternate-function mode with a push-pull drive
Methods
-------
.. method:: pinaf.__str__()
Return a string describing the alternate function.
.. method:: pinaf.index()
Return the alternate function index.
.. method:: pinaf.name()
Return the name of the alternate function.
.. method:: pinaf.reg()
Return the base register associated with the peripheral assigned to this
alternate function. For example, if the alternate function were TIM2_CH3
this would return stm.TIM2
.. data:: Pin.ANALOG
initialise the pin to analog mode
.. data:: Pin.IN
initialise the pin to input mode
.. data:: Pin.OUT_OD
initialise the pin to output mode with an open-drain drive
.. data:: Pin.OUT_PP
initialise the pin to output mode with a push-pull drive
.. data:: Pin.PULL_DOWN
enable the pull-down resistor on the pin
.. data:: Pin.PULL_NONE
don't enable any pull up or down resistors on the pin
.. data:: Pin.PULL_UP
enable the pull-up resistor on the pin
class PinAF -- Pin Alternate Functions
======================================
A Pin represents a physical pin on the microprocessor. Each pin
can have a variety of functions (GPIO, I2C SDA, etc). Each PinAF
object represents a particular function for a pin.
Usage Model::
x3 = pyb.Pin.board.X3
x3_af = x3.af_list()
x3_af will now contain an array of PinAF objects which are available on
pin X3.
For the pyboard, x3_af would contain:
[Pin.AF1_TIM2, Pin.AF2_TIM5, Pin.AF3_TIM9, Pin.AF7_USART2]
Normally, each peripheral would configure the af automatically, but sometimes
the same function is available on multiple pins, and having more control
is desired.
To configure X3 to expose TIM2_CH3, you could use::
pin = pyb.Pin(pyb.Pin.board.X3, mode=pyb.Pin.AF_PP, af=pyb.Pin.AF1_TIM2)
or::
pin = pyb.Pin(pyb.Pin.board.X3, mode=pyb.Pin.AF_PP, af=1)
Methods
-------
.. method:: pinaf.__str__()
Return a string describing the alternate function.
.. method:: pinaf.index()
Return the alternate function index.
.. method:: pinaf.name()
Return the name of the alternate function.
.. method:: pinaf.reg()
Return the base register associated with the peripheral assigned to this
alternate function. For example, if the alternate function were TIM2_CH3
this would return stm.TIM2

View File

@ -33,51 +33,46 @@ Methods
date and time. With 1 argument (being an 8-tuple) it sets the date
and time (and ``subseconds`` is reset to 255).
.. only:: port_pyboard
The 8-tuple has the following format:
The 8-tuple has the following format:
(year, month, day, weekday, hours, minutes, seconds, subseconds)
``weekday`` is 1-7 for Monday through Sunday.
``subseconds`` counts down from 255 to 0
(year, month, day, weekday, hours, minutes, seconds, subseconds)
.. only:: port_pyboard
``weekday`` is 1-7 for Monday through Sunday.
.. method:: RTC.wakeup(timeout, callback=None)
Set the RTC wakeup timer to trigger repeatedly at every ``timeout``
milliseconds. This trigger can wake the pyboard from both the sleep
states: :meth:`pyb.stop` and :meth:`pyb.standby`.
If ``timeout`` is ``None`` then the wakeup timer is disabled.
If ``callback`` is given then it is executed at every trigger of the
wakeup timer. ``callback`` must take exactly one argument.
.. method:: RTC.info()
Get information about the startup time and reset source.
- The lower 0xffff are the number of milliseconds the RTC took to
start up.
- Bit 0x10000 is set if a power-on reset occurred.
- Bit 0x20000 is set if an external reset occurred
.. method:: RTC.calibration(cal)
Get or set RTC calibration.
With no arguments, ``calibration()`` returns the current calibration
value, which is an integer in the range [-511 : 512]. With one
argument it sets the RTC calibration.
The RTC Smooth Calibration mechanism adjusts the RTC clock rate by
adding or subtracting the given number of ticks from the 32768 Hz
clock over a 32 second period (corresponding to 2^20 clock ticks.)
Each tick added will speed up the clock by 1 part in 2^20, or 0.954
ppm; likewise the RTC clock it slowed by negative values. The
usable calibration range is:
(-511 * 0.954) ~= -487.5 ppm up to (512 * 0.954) ~= 488.5 ppm
``subseconds`` counts down from 255 to 0
.. method:: RTC.wakeup(timeout, callback=None)
Set the RTC wakeup timer to trigger repeatedly at every ``timeout``
milliseconds. This trigger can wake the pyboard from both the sleep
states: :meth:`pyb.stop` and :meth:`pyb.standby`.
If ``timeout`` is ``None`` then the wakeup timer is disabled.
If ``callback`` is given then it is executed at every trigger of the
wakeup timer. ``callback`` must take exactly one argument.
.. method:: RTC.info()
Get information about the startup time and reset source.
- The lower 0xffff are the number of milliseconds the RTC took to
start up.
- Bit 0x10000 is set if a power-on reset occurred.
- Bit 0x20000 is set if an external reset occurred
.. method:: RTC.calibration(cal)
Get or set RTC calibration.
With no arguments, ``calibration()`` returns the current calibration
value, which is an integer in the range [-511 : 512]. With one
argument it sets the RTC calibration.
The RTC Smooth Calibration mechanism adjusts the RTC clock rate by
adding or subtracting the given number of ticks from the 32768 Hz
clock over a 32 second period (corresponding to 2^20 clock ticks.)
Each tick added will speed up the clock by 1 part in 2^20, or 0.954
ppm; likewise the RTC clock it slowed by negative values. The
usable calibration range is:
(-511 * 0.954) ~= -487.5 ppm up to (512 * 0.954) ~= 488.5 ppm

View File

@ -7,46 +7,42 @@ class SPI -- a master-driven serial protocol
SPI is a serial protocol that is driven by a master. At the physical level
there are 3 lines: SCK, MOSI, MISO.
.. only:: port_pyboard
See usage model of I2C; SPI is very similar. Main difference is
parameters to init the SPI bus::
See usage model of I2C; SPI is very similar. Main difference is
parameters to init the SPI bus::
from pyb import SPI
spi = SPI(1, SPI.MASTER, baudrate=600000, polarity=1, phase=0, crc=0x7)
from pyb import SPI
spi = SPI(1, SPI.MASTER, baudrate=600000, polarity=1, phase=0, crc=0x7)
Only required parameter is mode, SPI.MASTER or SPI.SLAVE. Polarity can be
0 or 1, and is the level the idle clock line sits at. Phase can be 0 or 1
to sample data on the first or second clock edge respectively. Crc can be
None for no CRC, or a polynomial specifier.
Only required parameter is mode, SPI.MASTER or SPI.SLAVE. Polarity can be
0 or 1, and is the level the idle clock line sits at. Phase can be 0 or 1
to sample data on the first or second clock edge respectively. Crc can be
None for no CRC, or a polynomial specifier.
Additional methods for SPI::
Additional methods for SPI::
data = spi.send_recv(b'1234') # send 4 bytes and receive 4 bytes
buf = bytearray(4)
spi.send_recv(b'1234', buf) # send 4 bytes and receive 4 into buf
spi.send_recv(buf, buf) # send/recv 4 bytes from/to buf
data = spi.send_recv(b'1234') # send 4 bytes and receive 4 bytes
buf = bytearray(4)
spi.send_recv(b'1234', buf) # send 4 bytes and receive 4 into buf
spi.send_recv(buf, buf) # send/recv 4 bytes from/to buf
Constructors
------------
.. only:: port_pyboard
.. class:: pyb.SPI(bus, ...)
.. class:: pyb.SPI(bus, ...)
Construct an SPI object on the given bus. ``bus`` can be 1 or 2, or
'X' or 'Y'. With no additional parameters, the SPI object is created but
not initialised (it has the settings from the last initialisation of
the bus, if any). If extra arguments are given, the bus is initialised.
See ``init`` for parameters of initialisation.
Construct an SPI object on the given bus. ``bus`` can be 1 or 2, or
'X' or 'Y'. With no additional parameters, the SPI object is created but
not initialised (it has the settings from the last initialisation of
the bus, if any). If extra arguments are given, the bus is initialised.
See ``init`` for parameters of initialisation.
The physical pins of the SPI busses are:
The physical pins of the SPI busses are:
- ``SPI(1)`` is on the X position: ``(NSS, SCK, MISO, MOSI) = (X5, X6, X7, X8) = (PA4, PA5, PA6, PA7)``
- ``SPI(2)`` is on the Y position: ``(NSS, SCK, MISO, MOSI) = (Y5, Y6, Y7, Y8) = (PB12, PB13, PB14, PB15)``
- ``SPI(1)`` is on the X position: ``(NSS, SCK, MISO, MOSI) = (X5, X6, X7, X8) = (PA4, PA5, PA6, PA7)``
- ``SPI(2)`` is on the Y position: ``(NSS, SCK, MISO, MOSI) = (Y5, Y6, Y7, Y8) = (PB12, PB13, PB14, PB15)``
At the moment, the NSS pin is not used by the SPI driver and is free
for other use.
At the moment, the NSS pin is not used by the SPI driver and is free
for other use.
Methods
-------
@ -55,78 +51,72 @@ Methods
Turn off the SPI bus.
.. only:: port_pyboard
.. method:: SPI.init(mode, baudrate=328125, \*, prescaler, polarity=1, phase=0, bits=8, firstbit=SPI.MSB, ti=False, crc=None)
.. method:: SPI.init(mode, baudrate=328125, \*, prescaler, polarity=1, phase=0, bits=8, firstbit=SPI.MSB, ti=False, crc=None)
Initialise the SPI bus with the given parameters:
Initialise the SPI bus with the given parameters:
- ``mode`` must be either ``SPI.MASTER`` or ``SPI.SLAVE``.
- ``baudrate`` is the SCK clock rate (only sensible for a master).
- ``prescaler`` is the prescaler to use to derive SCK from the APB bus frequency;
use of ``prescaler`` overrides ``baudrate``.
- ``polarity`` can be 0 or 1, and is the level the idle clock line sits at.
- ``phase`` can be 0 or 1 to sample data on the first or second clock edge
respectively.
- ``bits`` can be 8 or 16, and is the number of bits in each transferred word.
- ``firstbit`` can be ``SPI.MSB`` or ``SPI.LSB``.
- ``crc`` can be None for no CRC, or a polynomial specifier.
- ``mode`` must be either ``SPI.MASTER`` or ``SPI.SLAVE``.
- ``baudrate`` is the SCK clock rate (only sensible for a master).
- ``prescaler`` is the prescaler to use to derive SCK from the APB bus frequency;
use of ``prescaler`` overrides ``baudrate``.
- ``polarity`` can be 0 or 1, and is the level the idle clock line sits at.
- ``phase`` can be 0 or 1 to sample data on the first or second clock edge
respectively.
- ``bits`` can be 8 or 16, and is the number of bits in each transferred word.
- ``firstbit`` can be ``SPI.MSB`` or ``SPI.LSB``.
- ``crc`` can be None for no CRC, or a polynomial specifier.
Note that the SPI clock frequency will not always be the requested baudrate.
The hardware only supports baudrates that are the APB bus frequency
(see :meth:`pyb.freq`) divided by a prescaler, which can be 2, 4, 8, 16, 32,
64, 128 or 256. SPI(1) is on AHB2, and SPI(2) is on AHB1. For precise
control over the SPI clock frequency, specify ``prescaler`` instead of
``baudrate``.
Note that the SPI clock frequency will not always be the requested baudrate.
The hardware only supports baudrates that are the APB bus frequency
(see :meth:`pyb.freq`) divided by a prescaler, which can be 2, 4, 8, 16, 32,
64, 128 or 256. SPI(1) is on AHB2, and SPI(2) is on AHB1. For precise
control over the SPI clock frequency, specify ``prescaler`` instead of
``baudrate``.
Printing the SPI object will show you the computed baudrate and the chosen
prescaler.
Printing the SPI object will show you the computed baudrate and the chosen
prescaler.
.. method:: SPI.recv(recv, \*, timeout=5000)
.. only:: port_pyboard
Receive data on the bus:
.. method:: SPI.recv(recv, \*, timeout=5000)
Receive data on the bus:
- ``recv`` can be an integer, which is the number of bytes to receive,
or a mutable buffer, which will be filled with received bytes.
- ``timeout`` is the timeout in milliseconds to wait for the receive.
- ``recv`` can be an integer, which is the number of bytes to receive,
or a mutable buffer, which will be filled with received bytes.
- ``timeout`` is the timeout in milliseconds to wait for the receive.
Return value: if ``recv`` is an integer then a new buffer of the bytes received,
otherwise the same buffer that was passed in to ``recv``.
Return value: if ``recv`` is an integer then a new buffer of the bytes received,
otherwise the same buffer that was passed in to ``recv``.
.. method:: SPI.send(send, \*, timeout=5000)
.. method:: SPI.send(send, \*, timeout=5000)
Send data on the bus:
Send data on the bus:
- ``send`` is the data to send (an integer to send, or a buffer object).
- ``timeout`` is the timeout in milliseconds to wait for the send.
- ``send`` is the data to send (an integer to send, or a buffer object).
- ``timeout`` is the timeout in milliseconds to wait for the send.
Return value: ``None``.
Return value: ``None``.
.. method:: SPI.send_recv(send, recv=None, \*, timeout=5000)
Send and receive data on the bus at the same time:
.. method:: SPI.send_recv(send, recv=None, \*, timeout=5000)
- ``send`` is the data to send (an integer to send, or a buffer object).
- ``recv`` is a mutable buffer which will be filled with received bytes.
It can be the same as ``send``, or omitted. If omitted, a new buffer will
be created.
- ``timeout`` is the timeout in milliseconds to wait for the receive.
Send and receive data on the bus at the same time:
Return value: the buffer with the received bytes.
- ``send`` is the data to send (an integer to send, or a buffer object).
- ``recv`` is a mutable buffer which will be filled with received bytes.
It can be the same as ``send``, or omitted. If omitted, a new buffer will
be created.
- ``timeout`` is the timeout in milliseconds to wait for the receive.
Return value: the buffer with the received bytes.
Constants
---------
.. only:: port_pyboard
.. data:: SPI.MASTER
.. data:: SPI.SLAVE
.. data:: SPI.MASTER
.. data:: SPI.SLAVE
for initialising the SPI bus to master or slave mode
.. data:: SPI.LSB
.. data:: SPI.MSB
set the first bit to be the least or most significant bit
for initialising the SPI bus to master or slave mode
.. data:: SPI.LSB
.. data:: SPI.MSB
set the first bit to be the least or most significant bit

View File

@ -4,47 +4,45 @@
class Timer -- control internal timers
======================================
.. only:: port_pyboard
Timers can be used for a great variety of tasks. At the moment, only
the simplest case is implemented: that of calling a function periodically.
Timers can be used for a great variety of tasks. At the moment, only
the simplest case is implemented: that of calling a function periodically.
Each timer consists of a counter that counts up at a certain rate. The rate
at which it counts is the peripheral clock frequency (in Hz) divided by the
timer prescaler. When the counter reaches the timer period it triggers an
event, and the counter resets back to zero. By using the callback method,
the timer event can call a Python function.
Example usage to toggle an LED at a fixed frequency::
tim = pyb.Timer(4) # create a timer object using timer 4
tim.init(freq=2) # trigger at 2Hz
tim.callback(lambda t:pyb.LED(1).toggle())
Example using named function for the callback::
def tick(timer): # we will receive the timer object when being called
print(timer.counter()) # show current timer's counter value
tim = pyb.Timer(4, freq=1) # create a timer object using timer 4 - trigger at 1Hz
tim.callback(tick) # set the callback to our tick function
Further examples::
tim = pyb.Timer(4, freq=100) # freq in Hz
tim = pyb.Timer(4, prescaler=0, period=99)
tim.counter() # get counter (can also set)
tim.prescaler(2) # set prescaler (can also get)
tim.period(199) # set period (can also get)
tim.callback(lambda t: ...) # set callback for update interrupt (t=tim instance)
tim.callback(None) # clear callback
*Note:* Timer(2) and Timer(3) are used for PWM to set the intensity of LED(3)
and LED(4) respectively. But these timers are only configured for PWM if
the intensity of the relevant LED is set to a value between 1 and 254. If
the intensity feature of the LEDs is not used then these timers are free for
general purpose use. Similarly, Timer(5) controls the servo driver, and
Timer(6) is used for timed ADC/DAC reading/writing. It is recommended to
use the other timers in your programs.
Each timer consists of a counter that counts up at a certain rate. The rate
at which it counts is the peripheral clock frequency (in Hz) divided by the
timer prescaler. When the counter reaches the timer period it triggers an
event, and the counter resets back to zero. By using the callback method,
the timer event can call a Python function.
Example usage to toggle an LED at a fixed frequency::
tim = pyb.Timer(4) # create a timer object using timer 4
tim.init(freq=2) # trigger at 2Hz
tim.callback(lambda t:pyb.LED(1).toggle())
Example using named function for the callback::
def tick(timer): # we will receive the timer object when being called
print(timer.counter()) # show current timer's counter value
tim = pyb.Timer(4, freq=1) # create a timer object using timer 4 - trigger at 1Hz
tim.callback(tick) # set the callback to our tick function
Further examples::
tim = pyb.Timer(4, freq=100) # freq in Hz
tim = pyb.Timer(4, prescaler=0, period=99)
tim.counter() # get counter (can also set)
tim.prescaler(2) # set prescaler (can also get)
tim.period(199) # set period (can also get)
tim.callback(lambda t: ...) # set callback for update interrupt (t=tim instance)
tim.callback(None) # clear callback
*Note:* Timer(2) and Timer(3) are used for PWM to set the intensity of LED(3)
and LED(4) respectively. But these timers are only configured for PWM if
the intensity of the relevant LED is set to a value between 1 and 254. If
the intensity feature of the LEDs is not used then these timers are free for
general purpose use. Similarly, Timer(5) controls the servo driver, and
Timer(6) is used for timed ADC/DAC reading/writing. It is recommended to
use the other timers in your programs.
*Note:* Memory can't be allocated during a callback (an interrupt) and so
exceptions raised within a callback don't give much information. See
@ -57,184 +55,168 @@ Constructors
.. class:: pyb.Timer(id, ...)
.. only:: port_pyboard
Construct a new timer object of the given id. If additional
arguments are given, then the timer is initialised by ``init(...)``.
``id`` can be 1 to 14.
Construct a new timer object of the given id. If additional
arguments are given, then the timer is initialised by ``init(...)``.
``id`` can be 1 to 14.
Methods
-------
.. only:: port_pyboard
.. method:: Timer.init(\*, freq, prescaler, period)
.. method:: Timer.init(\*, freq, prescaler, period)
Initialise the timer. Initialisation must be either by frequency (in Hz)
or by prescaler and period::
tim.init(freq=100) # set the timer to trigger at 100Hz
tim.init(prescaler=83, period=999) # set the prescaler and period directly
Keyword arguments:
- ``freq`` --- specifies the periodic frequency of the timer. You might also
view this as the frequency with which the timer goes through one complete cycle.
- ``prescaler`` [0-0xffff] - specifies the value to be loaded into the
timer's Prescaler Register (PSC). The timer clock source is divided by
(``prescaler + 1``) to arrive at the timer clock. Timers 2-7 and 12-14
have a clock source of 84 MHz (pyb.freq()[2] \* 2), and Timers 1, and 8-11
have a clock source of 168 MHz (pyb.freq()[3] \* 2).
- ``period`` [0-0xffff] for timers 1, 3, 4, and 6-15. [0-0x3fffffff] for timers 2 & 5.
Specifies the value to be loaded into the timer's AutoReload
Register (ARR). This determines the period of the timer (i.e. when the
counter cycles). The timer counter will roll-over after ``period + 1``
timer clock cycles.
- ``mode`` can be one of:
- ``Timer.UP`` - configures the timer to count from 0 to ARR (default)
- ``Timer.DOWN`` - configures the timer to count from ARR down to 0.
- ``Timer.CENTER`` - configures the timer to count from 0 to ARR and
then back down to 0.
- ``div`` can be one of 1, 2, or 4. Divides the timer clock to determine
the sampling clock used by the digital filters.
- ``callback`` - as per Timer.callback()
- ``deadtime`` - specifies the amount of "dead" or inactive time between
transitions on complimentary channels (both channels will be inactive)
for this time). ``deadtime`` may be an integer between 0 and 1008, with
the following restrictions: 0-128 in steps of 1. 128-256 in steps of
2, 256-512 in steps of 8, and 512-1008 in steps of 16. ``deadtime``
measures ticks of ``source_freq`` divided by ``div`` clock ticks.
``deadtime`` is only available on timers 1 and 8.
You must either specify freq or both of period and prescaler.
Initialise the timer. Initialisation must be either by frequency (in Hz)
or by prescaler and period::
tim.init(freq=100) # set the timer to trigger at 100Hz
tim.init(prescaler=83, period=999) # set the prescaler and period directly
Keyword arguments:
- ``freq`` --- specifies the periodic frequency of the timer. You might also
view this as the frequency with which the timer goes through one complete cycle.
- ``prescaler`` [0-0xffff] - specifies the value to be loaded into the
timer's Prescaler Register (PSC). The timer clock source is divided by
(``prescaler + 1``) to arrive at the timer clock. Timers 2-7 and 12-14
have a clock source of 84 MHz (pyb.freq()[2] \* 2), and Timers 1, and 8-11
have a clock source of 168 MHz (pyb.freq()[3] \* 2).
- ``period`` [0-0xffff] for timers 1, 3, 4, and 6-15. [0-0x3fffffff] for timers 2 & 5.
Specifies the value to be loaded into the timer's AutoReload
Register (ARR). This determines the period of the timer (i.e. when the
counter cycles). The timer counter will roll-over after ``period + 1``
timer clock cycles.
- ``mode`` can be one of:
- ``Timer.UP`` - configures the timer to count from 0 to ARR (default)
- ``Timer.DOWN`` - configures the timer to count from ARR down to 0.
- ``Timer.CENTER`` - configures the timer to count from 0 to ARR and
then back down to 0.
- ``div`` can be one of 1, 2, or 4. Divides the timer clock to determine
the sampling clock used by the digital filters.
- ``callback`` - as per Timer.callback()
- ``deadtime`` - specifies the amount of "dead" or inactive time between
transitions on complimentary channels (both channels will be inactive)
for this time). ``deadtime`` may be an integer between 0 and 1008, with
the following restrictions: 0-128 in steps of 1. 128-256 in steps of
2, 256-512 in steps of 8, and 512-1008 in steps of 16. ``deadtime``
measures ticks of ``source_freq`` divided by ``div`` clock ticks.
``deadtime`` is only available on timers 1 and 8.
You must either specify freq or both of period and prescaler.
.. method:: Timer.deinit()
Deinitialises the timer.
.. only:: port_pyboard
Disables the callback (and the associated irq).
Disables the callback (and the associated irq).
Disables any channel callbacks (and the associated irq).
Stops the timer, and disables the timer peripheral.
.. only:: port_pyboard
.. method:: Timer.callback(fun)
.. method:: Timer.callback(fun)
Set the function to be called when the timer triggers.
``fun`` is passed 1 argument, the timer object.
If ``fun`` is ``None`` then the callback will be disabled.
Set the function to be called when the timer triggers.
``fun`` is passed 1 argument, the timer object.
If ``fun`` is ``None`` then the callback will be disabled.
.. only:: port_pyboard
.. method:: Timer.channel(channel, mode, ...)
.. method:: Timer.channel(channel, mode, ...)
If only a channel number is passed, then a previously initialized channel
object is returned (or ``None`` if there is no previous channel).
Otherwise, a TimerChannel object is initialized and returned.
Each channel can be configured to perform pwm, output compare, or
input capture. All channels share the same underlying timer, which means
that they share the same timer clock.
Keyword arguments:
- ``mode`` can be one of:
- ``Timer.PWM`` --- configure the timer in PWM mode (active high).
- ``Timer.PWM_INVERTED`` --- configure the timer in PWM mode (active low).
- ``Timer.OC_TIMING`` --- indicates that no pin is driven.
- ``Timer.OC_ACTIVE`` --- the pin will be made active when a compare match occurs (active is determined by polarity)
- ``Timer.OC_INACTIVE`` --- the pin will be made inactive when a compare match occurs.
- ``Timer.OC_TOGGLE`` --- the pin will be toggled when an compare match occurs.
- ``Timer.OC_FORCED_ACTIVE`` --- the pin is forced active (compare match is ignored).
- ``Timer.OC_FORCED_INACTIVE`` --- the pin is forced inactive (compare match is ignored).
- ``Timer.IC`` --- configure the timer in Input Capture mode.
- ``Timer.ENC_A`` --- configure the timer in Encoder mode. The counter only changes when CH1 changes.
- ``Timer.ENC_B`` --- configure the timer in Encoder mode. The counter only changes when CH2 changes.
- ``Timer.ENC_AB`` --- configure the timer in Encoder mode. The counter changes when CH1 or CH2 changes.
- ``callback`` - as per TimerChannel.callback()
- ``pin`` None (the default) or a Pin object. If specified (and not None)
this will cause the alternate function of the the indicated pin
to be configured for this timer channel. An error will be raised if
the pin doesn't support any alternate functions for this timer channel.
Keyword arguments for Timer.PWM modes:
- ``pulse_width`` - determines the initial pulse width value to use.
- ``pulse_width_percent`` - determines the initial pulse width percentage to use.
Keyword arguments for Timer.OC modes:
- ``compare`` - determines the initial value of the compare register.
- ``polarity`` can be one of:
- ``Timer.HIGH`` - output is active high
- ``Timer.LOW`` - output is active low
Optional keyword arguments for Timer.IC modes:
- ``polarity`` can be one of:
- ``Timer.RISING`` - captures on rising edge.
- ``Timer.FALLING`` - captures on falling edge.
- ``Timer.BOTH`` - captures on both edges.
Note that capture only works on the primary channel, and not on the
complimentary channels.
Notes for Timer.ENC modes:
- Requires 2 pins, so one or both pins will need to be configured to use
the appropriate timer AF using the Pin API.
- Read the encoder value using the timer.counter() method.
- Only works on CH1 and CH2 (and not on CH1N or CH2N)
- The channel number is ignored when setting the encoder mode.
PWM Example::
timer = pyb.Timer(2, freq=1000)
ch2 = timer.channel(2, pyb.Timer.PWM, pin=pyb.Pin.board.X2, pulse_width=8000)
ch3 = timer.channel(3, pyb.Timer.PWM, pin=pyb.Pin.board.X3, pulse_width=16000)
If only a channel number is passed, then a previously initialized channel
object is returned (or ``None`` if there is no previous channel).
.. only:: port_pyboard
Otherwise, a TimerChannel object is initialized and returned.
.. method:: Timer.counter([value])
Each channel can be configured to perform pwm, output compare, or
input capture. All channels share the same underlying timer, which means
that they share the same timer clock.
Get or set the timer counter.
Keyword arguments:
.. only:: port_pyboard
- ``mode`` can be one of:
.. method:: Timer.freq([value])
Get or set the frequency for the timer (changes prescaler and period if set).
- ``Timer.PWM`` --- configure the timer in PWM mode (active high).
- ``Timer.PWM_INVERTED`` --- configure the timer in PWM mode (active low).
- ``Timer.OC_TIMING`` --- indicates that no pin is driven.
- ``Timer.OC_ACTIVE`` --- the pin will be made active when a compare match occurs (active is determined by polarity)
- ``Timer.OC_INACTIVE`` --- the pin will be made inactive when a compare match occurs.
- ``Timer.OC_TOGGLE`` --- the pin will be toggled when an compare match occurs.
- ``Timer.OC_FORCED_ACTIVE`` --- the pin is forced active (compare match is ignored).
- ``Timer.OC_FORCED_INACTIVE`` --- the pin is forced inactive (compare match is ignored).
- ``Timer.IC`` --- configure the timer in Input Capture mode.
- ``Timer.ENC_A`` --- configure the timer in Encoder mode. The counter only changes when CH1 changes.
- ``Timer.ENC_B`` --- configure the timer in Encoder mode. The counter only changes when CH2 changes.
- ``Timer.ENC_AB`` --- configure the timer in Encoder mode. The counter changes when CH1 or CH2 changes.
.. only:: port_pyboard
- ``callback`` - as per TimerChannel.callback()
.. method:: Timer.period([value])
Get or set the period of the timer.
.. method:: Timer.prescaler([value])
Get or set the prescaler for the timer.
.. method:: Timer.source_freq()
Get the frequency of the source of the timer.
- ``pin`` None (the default) or a Pin object. If specified (and not None)
this will cause the alternate function of the the indicated pin
to be configured for this timer channel. An error will be raised if
the pin doesn't support any alternate functions for this timer channel.
Keyword arguments for Timer.PWM modes:
- ``pulse_width`` - determines the initial pulse width value to use.
- ``pulse_width_percent`` - determines the initial pulse width percentage to use.
Keyword arguments for Timer.OC modes:
- ``compare`` - determines the initial value of the compare register.
- ``polarity`` can be one of:
- ``Timer.HIGH`` - output is active high
- ``Timer.LOW`` - output is active low
Optional keyword arguments for Timer.IC modes:
- ``polarity`` can be one of:
- ``Timer.RISING`` - captures on rising edge.
- ``Timer.FALLING`` - captures on falling edge.
- ``Timer.BOTH`` - captures on both edges.
Note that capture only works on the primary channel, and not on the
complimentary channels.
Notes for Timer.ENC modes:
- Requires 2 pins, so one or both pins will need to be configured to use
the appropriate timer AF using the Pin API.
- Read the encoder value using the timer.counter() method.
- Only works on CH1 and CH2 (and not on CH1N or CH2N)
- The channel number is ignored when setting the encoder mode.
PWM Example::
timer = pyb.Timer(2, freq=1000)
ch2 = timer.channel(2, pyb.Timer.PWM, pin=pyb.Pin.board.X2, pulse_width=8000)
ch3 = timer.channel(3, pyb.Timer.PWM, pin=pyb.Pin.board.X3, pulse_width=16000)
.. method:: Timer.counter([value])
Get or set the timer counter.
.. method:: Timer.freq([value])
Get or set the frequency for the timer (changes prescaler and period if set).
.. method:: Timer.period([value])
Get or set the period of the timer.
.. method:: Timer.prescaler([value])
Get or set the prescaler for the timer.
.. method:: Timer.source_freq()
Get the frequency of the source of the timer.
class TimerChannel --- setup a channel for a timer
==================================================
@ -246,41 +228,37 @@ TimerChannel objects are created using the Timer.channel() method.
Methods
-------
.. only:: port_pyboard
.. method:: timerchannel.callback(fun)
.. method:: timerchannel.callback(fun)
Set the function to be called when the timer channel triggers.
``fun`` is passed 1 argument, the timer object.
If ``fun`` is ``None`` then the callback will be disabled.
Set the function to be called when the timer channel triggers.
``fun`` is passed 1 argument, the timer object.
If ``fun`` is ``None`` then the callback will be disabled.
.. method:: timerchannel.capture([value])
.. only:: port_pyboard
Get or set the capture value associated with a channel.
capture, compare, and pulse_width are all aliases for the same function.
capture is the logical name to use when the channel is in input capture mode.
.. method:: timerchannel.capture([value])
Get or set the capture value associated with a channel.
capture, compare, and pulse_width are all aliases for the same function.
capture is the logical name to use when the channel is in input capture mode.
.. method:: timerchannel.compare([value])
Get or set the compare value associated with a channel.
capture, compare, and pulse_width are all aliases for the same function.
compare is the logical name to use when the channel is in output compare mode.
.. method:: timerchannel.pulse_width([value])
Get or set the pulse width value associated with a channel.
capture, compare, and pulse_width are all aliases for the same function.
pulse_width is the logical name to use when the channel is in PWM mode.
In edge aligned mode, a pulse_width of ``period + 1`` corresponds to a duty cycle of 100%
In center aligned mode, a pulse width of ``period`` corresponds to a duty cycle of 100%
.. method:: timerchannel.pulse_width_percent([value])
Get or set the pulse width percentage associated with a channel. The value
is a number between 0 and 100 and sets the percentage of the timer period
for which the pulse is active. The value can be an integer or
floating-point number for more accuracy. For example, a value of 25 gives
a duty cycle of 25%.
.. method:: timerchannel.compare([value])
Get or set the compare value associated with a channel.
capture, compare, and pulse_width are all aliases for the same function.
compare is the logical name to use when the channel is in output compare mode.
.. method:: timerchannel.pulse_width([value])
Get or set the pulse width value associated with a channel.
capture, compare, and pulse_width are all aliases for the same function.
pulse_width is the logical name to use when the channel is in PWM mode.
In edge aligned mode, a pulse_width of ``period + 1`` corresponds to a duty cycle of 100%
In center aligned mode, a pulse width of ``period`` corresponds to a duty cycle of 100%
.. method:: timerchannel.pulse_width_percent([value])
Get or set the pulse width percentage associated with a channel. The value
is a number between 0 and 100 and sets the percentage of the timer period
for which the pulse is active. The value can be an integer or
floating-point number for more accuracy. For example, a value of 25 gives
a duty cycle of 25%.

View File

@ -16,12 +16,10 @@ UART objects can be created and initialised using::
uart = UART(1, 9600) # init with given baudrate
uart.init(9600, bits=8, parity=None, stop=1) # init with given parameters
.. only:: port_pyboard
Bits can be 7, 8 or 9. Parity can be None, 0 (even) or 1 (odd). Stop can be 1 or 2.
Bits can be 7, 8 or 9. Parity can be None, 0 (even) or 1 (odd). Stop can be 1 or 2.
*Note:* with parity=None, only 8 and 9 bits are supported. With parity enabled,
only 7 and 8 bits are supported.
*Note:* with parity=None, only 8 and 9 bits are supported. With parity enabled,
only 7 and 8 bits are supported.
A UART object acts like a `stream` object and reading and writing is done
using the standard stream methods::
@ -32,84 +30,76 @@ using the standard stream methods::
uart.readinto(buf) # read and store into the given buffer
uart.write('abc') # write the 3 characters
.. only:: port_pyboard
Individual characters can be read/written using::
Individual characters can be read/written using::
uart.readchar() # read 1 character and returns it as an integer
uart.writechar(42) # write 1 character
uart.readchar() # read 1 character and returns it as an integer
uart.writechar(42) # write 1 character
To check if there is anything to be read, use::
To check if there is anything to be read, use::
uart.any() # returns the number of characters waiting
uart.any() # returns the number of characters waiting
*Note:* The stream functions ``read``, ``write``, etc. are new in MicroPython v1.3.4.
Earlier versions use ``uart.send`` and ``uart.recv``.
*Note:* The stream functions ``read``, ``write``, etc. are new in MicroPython v1.3.4.
Earlier versions use ``uart.send`` and ``uart.recv``.
Constructors
------------
.. only:: port_pyboard
.. class:: pyb.UART(bus, ...)
.. class:: pyb.UART(bus, ...)
Construct a UART object on the given bus. ``bus`` can be 1-6, or 'XA', 'XB', 'YA', or 'YB'.
With no additional parameters, the UART object is created but not
initialised (it has the settings from the last initialisation of
the bus, if any). If extra arguments are given, the bus is initialised.
See ``init`` for parameters of initialisation.
Construct a UART object on the given bus. ``bus`` can be 1-6, or 'XA', 'XB', 'YA', or 'YB'.
With no additional parameters, the UART object is created but not
initialised (it has the settings from the last initialisation of
the bus, if any). If extra arguments are given, the bus is initialised.
See ``init`` for parameters of initialisation.
The physical pins of the UART busses are:
- ``UART(4)`` is on ``XA``: ``(TX, RX) = (X1, X2) = (PA0, PA1)``
- ``UART(1)`` is on ``XB``: ``(TX, RX) = (X9, X10) = (PB6, PB7)``
- ``UART(6)`` is on ``YA``: ``(TX, RX) = (Y1, Y2) = (PC6, PC7)``
- ``UART(3)`` is on ``YB``: ``(TX, RX) = (Y9, Y10) = (PB10, PB11)``
- ``UART(2)`` is on: ``(TX, RX) = (X3, X4) = (PA2, PA3)``
The physical pins of the UART busses are:
The Pyboard Lite supports UART(1), UART(2) and UART(6) only. Pins are as above except:
- ``UART(4)`` is on ``XA``: ``(TX, RX) = (X1, X2) = (PA0, PA1)``
- ``UART(1)`` is on ``XB``: ``(TX, RX) = (X9, X10) = (PB6, PB7)``
- ``UART(6)`` is on ``YA``: ``(TX, RX) = (Y1, Y2) = (PC6, PC7)``
- ``UART(3)`` is on ``YB``: ``(TX, RX) = (Y9, Y10) = (PB10, PB11)``
- ``UART(2)`` is on: ``(TX, RX) = (X3, X4) = (PA2, PA3)``
- ``UART(2)`` is on: ``(TX, RX) = (X1, X2) = (PA2, PA3)``
The Pyboard Lite supports UART(1), UART(2) and UART(6) only. Pins are as above except:
- ``UART(2)`` is on: ``(TX, RX) = (X1, X2) = (PA2, PA3)``
Methods
-------
.. only:: port_pyboard
.. method:: UART.init(baudrate, bits=8, parity=None, stop=1, \*, timeout=1000, flow=0, timeout_char=0, read_buf_len=64)
.. method:: UART.init(baudrate, bits=8, parity=None, stop=1, \*, timeout=1000, flow=0, timeout_char=0, read_buf_len=64)
Initialise the UART bus with the given parameters:
- ``baudrate`` is the clock rate.
- ``bits`` is the number of bits per character, 7, 8 or 9.
- ``parity`` is the parity, ``None``, 0 (even) or 1 (odd).
- ``stop`` is the number of stop bits, 1 or 2.
- ``flow`` sets the flow control type. Can be 0, ``UART.RTS``, ``UART.CTS``
or ``UART.RTS | UART.CTS``.
- ``timeout`` is the timeout in milliseconds to wait for writing/reading the first character.
- ``timeout_char`` is the timeout in milliseconds to wait between characters while writing or reading.
- ``read_buf_len`` is the character length of the read buffer (0 to disable).
This method will raise an exception if the baudrate could not be set within
5% of the desired value. The minimum baudrate is dictated by the frequency
of the bus that the UART is on; UART(1) and UART(6) are APB2, the rest are on
APB1. The default bus frequencies give a minimum baudrate of 1300 for
UART(1) and UART(6) and 650 for the others. Use :func:`pyb.freq <pyb.freq>`
to reduce the bus frequencies to get lower baudrates.
*Note:* with parity=None, only 8 and 9 bits are supported. With parity enabled,
only 7 and 8 bits are supported.
Initialise the UART bus with the given parameters:
- ``baudrate`` is the clock rate.
- ``bits`` is the number of bits per character, 7, 8 or 9.
- ``parity`` is the parity, ``None``, 0 (even) or 1 (odd).
- ``stop`` is the number of stop bits, 1 or 2.
- ``flow`` sets the flow control type. Can be 0, ``UART.RTS``, ``UART.CTS``
or ``UART.RTS | UART.CTS``.
- ``timeout`` is the timeout in milliseconds to wait for writing/reading the first character.
- ``timeout_char`` is the timeout in milliseconds to wait between characters while writing or reading.
- ``read_buf_len`` is the character length of the read buffer (0 to disable).
This method will raise an exception if the baudrate could not be set within
5% of the desired value. The minimum baudrate is dictated by the frequency
of the bus that the UART is on; UART(1) and UART(6) are APB2, the rest are on
APB1. The default bus frequencies give a minimum baudrate of 1300 for
UART(1) and UART(6) and 650 for the others. Use :func:`pyb.freq <pyb.freq>`
to reduce the bus frequencies to get lower baudrates.
*Note:* with parity=None, only 8 and 9 bits are supported. With parity enabled,
only 7 and 8 bits are supported.
.. method:: UART.deinit()
Turn off the UART bus.
.. only:: port_pyboard
.. method:: UART.any()
.. method:: UART.any()
Returns the number of bytes waiting (may be 0).
Returns the number of bytes waiting (may be 0).
.. method:: UART.read([nbytes])
@ -120,13 +110,11 @@ Methods
If ``nbytes`` is not given then the method reads as much data as possible. It
returns after the timeout has elapsed.
.. only:: port_pyboard
*Note:* for 9 bit characters each character takes two bytes, ``nbytes`` must
be even, and the number of characters is ``nbytes/2``.
*Note:* for 9 bit characters each character takes two bytes, ``nbytes`` must
be even, and the number of characters is ``nbytes/2``.
Return value: a bytes object containing the bytes read in. Returns ``None``
on timeout.
Return value: a bytes object containing the bytes read in. Returns ``None``
on timeout.
.. method:: UART.readchar()
@ -152,22 +140,18 @@ Methods
.. method:: UART.write(buf)
.. only:: port_pyboard
Write the buffer of bytes to the bus. If characters are 7 or 8 bits wide
then each byte is one character. If characters are 9 bits wide then two
bytes are used for each character (little endian), and ``buf`` must contain
an even number of bytes.
Write the buffer of bytes to the bus. If characters are 7 or 8 bits wide
then each byte is one character. If characters are 9 bits wide then two
bytes are used for each character (little endian), and ``buf`` must contain
an even number of bytes.
Return value: number of bytes written. If a timeout occurs and no bytes
were written returns ``None``.
Return value: number of bytes written. If a timeout occurs and no bytes
were written returns ``None``.
.. method:: UART.writechar(char)
.. only:: port_pyboard
.. method:: UART.writechar(char)
Write a single character on the bus. ``char`` is an integer to write.
Return value: ``None``. See note below if CTS flow control is used.
Write a single character on the bus. ``char`` is an integer to write.
Return value: ``None``. See note below if CTS flow control is used.
.. method:: UART.sendbreak()
@ -178,68 +162,64 @@ Methods
Constants
---------
.. only:: port_pyboard
.. data:: UART.RTS
UART.CTS
.. data:: UART.RTS
.. data:: UART.CTS
to select the flow control type.
to select the flow control type.
Flow Control
------------
.. only:: port_pyboard
On Pyboards V1 and V1.1 ``UART(2)`` and ``UART(3)`` support RTS/CTS hardware flow control
using the following pins:
On Pyboards V1 and V1.1 ``UART(2)`` and ``UART(3)`` support RTS/CTS hardware flow control
using the following pins:
- ``UART(2)`` is on: ``(TX, RX, nRTS, nCTS) = (X3, X4, X2, X1) = (PA2, PA3, PA1, PA0)``
- ``UART(3)`` is on :``(TX, RX, nRTS, nCTS) = (Y9, Y10, Y7, Y6) = (PB10, PB11, PB14, PB13)``
- ``UART(2)`` is on: ``(TX, RX, nRTS, nCTS) = (X3, X4, X2, X1) = (PA2, PA3, PA1, PA0)``
- ``UART(3)`` is on :``(TX, RX, nRTS, nCTS) = (Y9, Y10, Y7, Y6) = (PB10, PB11, PB14, PB13)``
On the Pyboard Lite only ``UART(2)`` supports flow control on these pins:
On the Pyboard Lite only ``UART(2)`` supports flow control on these pins:
``(TX, RX, nRTS, nCTS) = (X1, X2, X4, X3) = (PA2, PA3, PA1, PA0)``
``(TX, RX, nRTS, nCTS) = (X1, X2, X4, X3) = (PA2, PA3, PA1, PA0)``
In the following paragraphs the term "target" refers to the device connected to
the UART.
In the following paragraphs the term "target" refers to the device connected to
the UART.
When the UART's ``init()`` method is called with ``flow`` set to one or both of
``UART.RTS`` and ``UART.CTS`` the relevant flow control pins are configured.
``nRTS`` is an active low output, ``nCTS`` is an active low input with pullup
enabled. To achieve flow control the Pyboard's ``nCTS`` signal should be connected
to the target's ``nRTS`` and the Pyboard's ``nRTS`` to the target's ``nCTS``.
When the UART's ``init()`` method is called with ``flow`` set to one or both of
``UART.RTS`` and ``UART.CTS`` the relevant flow control pins are configured.
``nRTS`` is an active low output, ``nCTS`` is an active low input with pullup
enabled. To achieve flow control the Pyboard's ``nCTS`` signal should be connected
to the target's ``nRTS`` and the Pyboard's ``nRTS`` to the target's ``nCTS``.
CTS: target controls Pyboard transmitter
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CTS: target controls Pyboard transmitter
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If CTS flow control is enabled the write behaviour is as follows:
If CTS flow control is enabled the write behaviour is as follows:
If the Pyboard's ``UART.write(buf)`` method is called, transmission will stall for
any periods when ``nCTS`` is ``False``. This will result in a timeout if the entire
buffer was not transmitted in the timeout period. The method returns the number of
bytes written, enabling the user to write the remainder of the data if required. In
the event of a timeout, a character will remain in the UART pending ``nCTS``. The
number of bytes composing this character will be included in the return value.
If the Pyboard's ``UART.write(buf)`` method is called, transmission will stall for
any periods when ``nCTS`` is ``False``. This will result in a timeout if the entire
buffer was not transmitted in the timeout period. The method returns the number of
bytes written, enabling the user to write the remainder of the data if required. In
the event of a timeout, a character will remain in the UART pending ``nCTS``. The
number of bytes composing this character will be included in the return value.
If ``UART.writechar()`` is called when ``nCTS`` is ``False`` the method will time
out unless the target asserts ``nCTS`` in time. If it times out ``OSError 116``
will be raised. The character will be transmitted as soon as the target asserts ``nCTS``.
If ``UART.writechar()`` is called when ``nCTS`` is ``False`` the method will time
out unless the target asserts ``nCTS`` in time. If it times out ``OSError 116``
will be raised. The character will be transmitted as soon as the target asserts ``nCTS``.
RTS: Pyboard controls target's transmitter
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
RTS: Pyboard controls target's transmitter
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If RTS flow control is enabled, behaviour is as follows:
If buffered input is used (``read_buf_len`` > 0), incoming characters are buffered.
If the buffer becomes full, the next character to arrive will cause ``nRTS`` to go
``False``: the target should cease transmission. ``nRTS`` will go ``True`` when
characters are read from the buffer.
Note that the ``any()`` method returns the number of bytes in the buffer. Assume a
buffer length of ``N`` bytes. If the buffer becomes full, and another character arrives,
``nRTS`` will be set False, and ``any()`` will return the count ``N``. When
characters are read the additional character will be placed in the buffer and will
be included in the result of a subsequent ``any()`` call.
If buffered input is not used (``read_buf_len`` == 0) the arrival of a character will
cause ``nRTS`` to go ``False`` until the character is read.
If RTS flow control is enabled, behaviour is as follows:
If buffered input is used (``read_buf_len`` > 0), incoming characters are buffered.
If the buffer becomes full, the next character to arrive will cause ``nRTS`` to go
``False``: the target should cease transmission. ``nRTS`` will go ``True`` when
characters are read from the buffer.
Note that the ``any()`` method returns the number of bytes in the buffer. Assume a
buffer length of ``N`` bytes. If the buffer becomes full, and another character arrives,
``nRTS`` will be set False, and ``any()`` will return the count ``N``. When
characters are read the additional character will be placed in the buffer and will
be included in the result of a subsequent ``any()`` call.
If buffered input is not used (``read_buf_len`` == 0) the arrival of a character will
cause ``nRTS`` to go ``False`` until the character is read.

View File

@ -114,98 +114,94 @@ Interrupt related functions
Power related functions
-----------------------
.. only:: port_pyboard
.. function:: freq([sysclk[, hclk[, pclk1[, pclk2]]]])
.. function:: freq([sysclk[, hclk[, pclk1[, pclk2]]]])
If given no arguments, returns a tuple of clock frequencies:
(sysclk, hclk, pclk1, pclk2).
These correspond to:
- sysclk: frequency of the CPU
- hclk: frequency of the AHB bus, core memory and DMA
- pclk1: frequency of the APB1 bus
- pclk2: frequency of the APB2 bus
If given any arguments then the function sets the frequency of the CPU,
and the busses if additional arguments are given. Frequencies are given in
Hz. Eg freq(120000000) sets sysclk (the CPU frequency) to 120MHz. Note that
not all values are supported and the largest supported frequency not greater
than the given value will be selected.
Supported sysclk frequencies are (in MHz): 8, 16, 24, 30, 32, 36, 40, 42, 48,
54, 56, 60, 64, 72, 84, 96, 108, 120, 144, 168.
The maximum frequency of hclk is 168MHz, of pclk1 is 42MHz, and of pclk2 is
84MHz. Be sure not to set frequencies above these values.
The hclk, pclk1 and pclk2 frequencies are derived from the sysclk frequency
using a prescaler (divider). Supported prescalers for hclk are: 1, 2, 4, 8,
16, 64, 128, 256, 512. Supported prescalers for pclk1 and pclk2 are: 1, 2,
4, 8. A prescaler will be chosen to best match the requested frequency.
A sysclk frequency of
8MHz uses the HSE (external crystal) directly and 16MHz uses the HSI
(internal oscillator) directly. The higher frequencies use the HSE to
drive the PLL (phase locked loop), and then use the output of the PLL.
Note that if you change the frequency while the USB is enabled then
the USB may become unreliable. It is best to change the frequency
in boot.py, before the USB peripheral is started. Also note that sysclk
frequencies below 36MHz do not allow the USB to function correctly.
.. function:: wfi()
Wait for an internal or external interrupt.
This executes a ``wfi`` instruction which reduces power consumption
of the MCU until any interrupt occurs (be it internal or external),
at which point execution continues. Note that the system-tick interrupt
occurs once every millisecond (1000Hz) so this function will block for
at most 1ms.
.. function:: stop()
Put the pyboard in a "sleeping" state.
This reduces power consumption to less than 500 uA. To wake from this
sleep state requires an external interrupt or a real-time-clock event.
Upon waking execution continues where it left off.
See :meth:`rtc.wakeup` to configure a real-time-clock wakeup event.
.. function:: standby()
Put the pyboard into a "deep sleep" state.
This reduces power consumption to less than 50 uA. To wake from this
sleep state requires a real-time-clock event, or an external interrupt
on X1 (PA0=WKUP) or X18 (PC13=TAMP1).
Upon waking the system undergoes a hard reset.
See :meth:`rtc.wakeup` to configure a real-time-clock wakeup event.
If given no arguments, returns a tuple of clock frequencies:
(sysclk, hclk, pclk1, pclk2).
These correspond to:
- sysclk: frequency of the CPU
- hclk: frequency of the AHB bus, core memory and DMA
- pclk1: frequency of the APB1 bus
- pclk2: frequency of the APB2 bus
If given any arguments then the function sets the frequency of the CPU,
and the busses if additional arguments are given. Frequencies are given in
Hz. Eg freq(120000000) sets sysclk (the CPU frequency) to 120MHz. Note that
not all values are supported and the largest supported frequency not greater
than the given value will be selected.
Supported sysclk frequencies are (in MHz): 8, 16, 24, 30, 32, 36, 40, 42, 48,
54, 56, 60, 64, 72, 84, 96, 108, 120, 144, 168.
The maximum frequency of hclk is 168MHz, of pclk1 is 42MHz, and of pclk2 is
84MHz. Be sure not to set frequencies above these values.
The hclk, pclk1 and pclk2 frequencies are derived from the sysclk frequency
using a prescaler (divider). Supported prescalers for hclk are: 1, 2, 4, 8,
16, 64, 128, 256, 512. Supported prescalers for pclk1 and pclk2 are: 1, 2,
4, 8. A prescaler will be chosen to best match the requested frequency.
A sysclk frequency of
8MHz uses the HSE (external crystal) directly and 16MHz uses the HSI
(internal oscillator) directly. The higher frequencies use the HSE to
drive the PLL (phase locked loop), and then use the output of the PLL.
Note that if you change the frequency while the USB is enabled then
the USB may become unreliable. It is best to change the frequency
in boot.py, before the USB peripheral is started. Also note that sysclk
frequencies below 36MHz do not allow the USB to function correctly.
.. function:: wfi()
Wait for an internal or external interrupt.
This executes a ``wfi`` instruction which reduces power consumption
of the MCU until any interrupt occurs (be it internal or external),
at which point execution continues. Note that the system-tick interrupt
occurs once every millisecond (1000Hz) so this function will block for
at most 1ms.
.. function:: stop()
Put the pyboard in a "sleeping" state.
This reduces power consumption to less than 500 uA. To wake from this
sleep state requires an external interrupt or a real-time-clock event.
Upon waking execution continues where it left off.
See :meth:`rtc.wakeup` to configure a real-time-clock wakeup event.
.. function:: standby()
Put the pyboard into a "deep sleep" state.
This reduces power consumption to less than 50 uA. To wake from this
sleep state requires a real-time-clock event, or an external interrupt
on X1 (PA0=WKUP) or X18 (PC13=TAMP1).
Upon waking the system undergoes a hard reset.
See :meth:`rtc.wakeup` to configure a real-time-clock wakeup event.
Miscellaneous functions
-----------------------
.. only:: port_pyboard
.. function:: have_cdc()
.. function:: have_cdc()
Return True if USB is connected as a serial device, False otherwise.
.. note:: This function is deprecated. Use pyb.USB_VCP().isconnected() instead.
.. function:: hid((buttons, x, y, z))
Takes a 4-tuple (or list) and sends it to the USB host (the PC) to
signal a HID mouse-motion event.
.. note:: This function is deprecated. Use :meth:`pyb.USB_HID.send()` instead.
.. function:: info([dump_alloc_table])
Print out lots of information about the board.
Return True if USB is connected as a serial device, False otherwise.
.. note:: This function is deprecated. Use pyb.USB_VCP().isconnected() instead.
.. function:: hid((buttons, x, y, z))
Takes a 4-tuple (or list) and sends it to the USB host (the PC) to
signal a HID mouse-motion event.
.. note:: This function is deprecated. Use :meth:`pyb.USB_HID.send()` instead.
.. function:: info([dump_alloc_table])
Print out lots of information about the board.
.. function:: main(filename)
@ -214,58 +210,52 @@ Miscellaneous functions
It only makes sense to call this function from within boot.py.
.. only:: port_pyboard
.. function:: mount(device, mountpoint, \*, readonly=False, mkfs=False)
.. function:: mount(device, mountpoint, \*, readonly=False, mkfs=False)
Mount a block device and make it available as part of the filesystem.
``device`` must be an object that provides the block protocol:
- ``readblocks(self, blocknum, buf)``
- ``writeblocks(self, blocknum, buf)`` (optional)
- ``count(self)``
- ``sync(self)`` (optional)
``readblocks`` and ``writeblocks`` should copy data between ``buf`` and
the block device, starting from block number ``blocknum`` on the device.
``buf`` will be a bytearray with length a multiple of 512. If
``writeblocks`` is not defined then the device is mounted read-only.
The return value of these two functions is ignored.
``count`` should return the number of blocks available on the device.
``sync``, if implemented, should sync the data on the device.
The parameter ``mountpoint`` is the location in the root of the filesystem
to mount the device. It must begin with a forward-slash.
If ``readonly`` is ``True``, then the device is mounted read-only,
otherwise it is mounted read-write.
If ``mkfs`` is ``True``, then a new filesystem is created if one does not
already exist.
To unmount a device, pass ``None`` as the device and the mount location
as ``mountpoint``.
Mount a block device and make it available as part of the filesystem.
``device`` must be an object that provides the block protocol:
- ``readblocks(self, blocknum, buf)``
- ``writeblocks(self, blocknum, buf)`` (optional)
- ``count(self)``
- ``sync(self)`` (optional)
``readblocks`` and ``writeblocks`` should copy data between ``buf`` and
the block device, starting from block number ``blocknum`` on the device.
``buf`` will be a bytearray with length a multiple of 512. If
``writeblocks`` is not defined then the device is mounted read-only.
The return value of these two functions is ignored.
``count`` should return the number of blocks available on the device.
``sync``, if implemented, should sync the data on the device.
The parameter ``mountpoint`` is the location in the root of the filesystem
to mount the device. It must begin with a forward-slash.
If ``readonly`` is ``True``, then the device is mounted read-only,
otherwise it is mounted read-write.
If ``mkfs`` is ``True``, then a new filesystem is created if one does not
already exist.
To unmount a device, pass ``None`` as the device and the mount location
as ``mountpoint``.
.. function:: repl_uart(uart)
Get or set the UART object where the REPL is repeated on.
.. only:: port_pyboard
.. function:: rng()
.. function:: rng()
Return a 30-bit hardware generated random number.
Return a 30-bit hardware generated random number.
.. function:: sync()
Sync all file systems.
.. only:: port_pyboard
.. function:: unique_id()
.. function:: unique_id()
Returns a string of 12 bytes (96 bits), which is the unique ID of the MCU.
Returns a string of 12 bytes (96 bits), which is the unique ID of the MCU.
.. function:: usb_mode([modestr], vid=0xf055, pid=0x9801, hid=pyb.hid_mouse)
@ -298,25 +288,23 @@ Miscellaneous functions
Classes
-------
.. only:: port_pyboard
.. toctree::
:maxdepth: 1
.. toctree::
:maxdepth: 1
pyb.Accel.rst
pyb.ADC.rst
pyb.CAN.rst
pyb.DAC.rst
pyb.ExtInt.rst
pyb.I2C.rst
pyb.LCD.rst
pyb.LED.rst
pyb.Pin.rst
pyb.RTC.rst
pyb.Servo.rst
pyb.SPI.rst
pyb.Switch.rst
pyb.Timer.rst
pyb.UART.rst
pyb.USB_HID.rst
pyb.USB_VCP.rst
pyb.Accel.rst
pyb.ADC.rst
pyb.CAN.rst
pyb.DAC.rst
pyb.ExtInt.rst
pyb.I2C.rst
pyb.LCD.rst
pyb.LED.rst
pyb.Pin.rst
pyb.RTC.rst
pyb.Servo.rst
pyb.SPI.rst
pyb.Switch.rst
pyb.Timer.rst
pyb.UART.rst
pyb.USB_HID.rst
pyb.USB_VCP.rst