mirrors
/
micropython
mirror of https://github.com/micropython/micropython.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

esp32/esp32_rmt: Add RMT.PULSE_MAX constant. 

If you have a variable frequency and pulse width, and you want to optimize
pulse resolution, then you must do a calculation beforehand to ensure you
normalize the array to keep all list values within bound.  That calculation
requires RMT.source_freq(), RMT.clock_div(), and this 32767 constant.

Signed-off-by: Mark Blakeney <mark.blakeney@bullet-systems.net>
This commit is contained in:
Mark Blakeney 2023-10-31 14:24:43 +10:00 committed by Damien George
parent fbb7c32040
commit 2888c5b230
2 changed files with 15 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
docs/library/esp32.rst
View File

@ -193,7 +193,7 @@ numbers specified in ``write_pulses`` are multiplied by the resolution to
define the pulses.
``clock_div`` is an 8-bit divider (0-255) and each pulse can be defined by
multiplying the resolution by a 15-bit (0-32,768) number. There are eight
multiplying the resolution by a 15-bit (1-``PULSE_MAX``) number. There are eight
channels (0-7) and each can have a different clock divider.
So, in the example above, the 80MHz clock is divided by 8. Thus the
@ -264,10 +264,10 @@ For more details see Espressif's `ESP-IDF RMT documentation.
**Mode 3:** *duration* and *data* are lists or tuples of equal length,
specifying individual durations and the output level for each.
Durations are in integer units of the channel resolution (as described
above), between 1 and 32767 units. Output levels are any value that can
be converted to a boolean, with ``True`` representing high voltage and
``False`` representing low.
Durations are in integer units of the channel resolution (as
described above), between 1 and ``PULSE_MAX`` units. Output levels
are any value that can be converted to a boolean, with ``True``
representing high voltage and ``False`` representing low.
If transmission of an earlier sequence is in progress then this method will
block until that transmission is complete before beginning the new sequence.
@ -290,6 +290,13 @@ For more details see Espressif's `ESP-IDF RMT documentation.
Passing in no argument will not change the channel. This function returns
the current channel number.
Constants
---------
.. data:: RMT.PULSE_MAX
Maximum integer that can be set for a pulse duration.
Ultra-Low-Power co-processor
----------------------------

3
ports/esp32/esp32_rmt.c
View File

@ -368,6 +368,9 @@ STATIC const mp_rom_map_elem_t esp32_rmt_locals_dict_table[] = {
// Class methods
{ MP_ROM_QSTR(MP_QSTR_source_freq), MP_ROM_PTR(&esp32_rmt_source_obj) },
// Constants
{ MP_ROM_QSTR(MP_QSTR_PULSE_MAX), MP_ROM_INT(32767) },
};
STATIC MP_DEFINE_CONST_DICT(esp32_rmt_locals_dict, esp32_rmt_locals_dict_table);