157 lines
4.5 KiB
ReStructuredText
157 lines
4.5 KiB
ReStructuredText
:mod:`machine` --- functions related to the board
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=================================================
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.. module:: machine
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:synopsis: functions related to the board
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The ``machine`` module contains specific functions related to the board.
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Reset related functions
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-----------------------
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.. function:: reset()
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Resets the device in a manner similar to pushing the external RESET
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button.
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.. function:: reset_cause()
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Get the reset cause. See :ref:`constants <machine_constants>` for the possible return values.
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Interrupt related functions
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---------------------------
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.. function:: disable_irq()
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Disable interrupt requests.
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Returns the previous IRQ state: ``False``/``True`` for disabled/enabled IRQs
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respectively. This return value can be passed to enable_irq to restore
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the IRQ to its original state.
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.. function:: enable_irq(state=True)
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Enable interrupt requests.
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If ``state`` is ``True`` (the default value) then IRQs are enabled.
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If ``state`` is ``False`` then IRQs are disabled. The most common use of
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this function is to pass it the value returned by ``disable_irq`` to
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exit a critical section.
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Power related functions
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-----------------------
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.. function:: freq()
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.. only:: not port_wipy
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Returns CPU frequency in hertz.
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.. only:: port_wipy
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Returns a tuple of clock frequencies: ``(sysclk,)``
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These correspond to:
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- sysclk: frequency of the CPU
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.. function:: idle()
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Gates the clock to the CPU, useful to reduce power consumption at any time during
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short or long periods. Peripherals continue working and execution resumes as soon
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as any interrupt is triggered (on many ports this includes system timer
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interrupt occuring at regular intervals on the order of millisecond).
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.. function:: sleep()
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Stops the CPU and disables all peripherals except for WLAN. Execution is resumed from
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the point where the sleep was requested. For wake up to actually happen, wake sources
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should be configured first.
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.. function:: deepsleep()
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Stops the CPU and all peripherals (including networking interfaces, if any). Execution
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is resumed from the main script, just as with a reset. The reset cause can be checked
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to know that we are coming from ``machine.DEEPSLEEP``. For wake up to actually happen,
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wake sources should be configured first, like ``Pin`` change or ``RTC`` timeout.
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.. only:: port_wipy
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.. function:: wake_reason()
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Get the wake reason. See :ref:`constants <machine_constants>` for the possible return values.
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Miscellaneous functions
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-----------------------
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.. only:: port_wipy
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.. function:: main(filename)
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Set the filename of the main script to run after boot.py is finished. If
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this function is not called then the default file main.py will be executed.
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It only makes sense to call this function from within boot.py.
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.. function:: rng()
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Return a 24-bit software generated random number.
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.. function:: unique_id()
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Returns a byte string with a unique idenifier of a board/SoC. It will vary
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from a board/SoC instance to another, if underlying hardware allows. Length
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varies by hardware (so use substring of a full value if you expect a short
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ID). In some MicroPython ports, ID corresponds to the network MAC address.
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.. function:: time_pulse_us(pin, pulse_level, timeout_us=1000000)
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Time a pulse on the given `pin`, and return the duration of the pulse in
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microseconds. The `pulse_level` argument should be 0 to time a low pulse
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or 1 to time a high pulse.
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The function first waits while the pin input is different to the `pulse_level`
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parameter, then times the duration that the pin is equal to `pulse_level`.
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If the pin is already equal to `pulse_level` then timing starts straight away.
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The function will raise an OSError with ETIMEDOUT if either of the waits is
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longer than the given timeout value (which is in microseconds).
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.. _machine_constants:
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Constants
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---------
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.. data:: machine.IDLE
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.. data:: machine.SLEEP
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.. data:: machine.DEEPSLEEP
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irq wake values
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.. data:: machine.POWER_ON
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.. data:: machine.HARD_RESET
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.. data:: machine.WDT_RESET
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.. data:: machine.DEEPSLEEP_RESET
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.. data:: machine.SOFT_RESET
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reset causes
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.. data:: machine.WLAN_WAKE
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.. data:: machine.PIN_WAKE
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.. data:: machine.RTC_WAKE
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wake reasons
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Classes
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-------
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.. toctree::
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:maxdepth: 1
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machine.ADC.rst
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machine.I2C.rst
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machine.Pin.rst
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machine.RTC.rst
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machine.SD.rst
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machine.SPI.rst
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machine.Timer.rst
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machine.UART.rst
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machine.WDT.rst
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