espressif/esp-idf
1
0
Fork 1
mirror of https://github.com/espressif/esp-idf.git synced 2025-11-03 00:21:44 +01:00
Code Issues Packages Projects Releases Wiki Activity

MCPWM: expose API to set timer resolution

Browse Source 
Closes https://github.com/espressif/esp-idf/issues/1101
This commit is contained in:
SalimTerryLi
2021-07-28 17:09:02 +08:00
parent 1063f0c9dd
commit f4314af913
6 changed files with 178 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
docs/en/api-reference/peripherals/mcpwm.rst
View File

@@ -35,6 +35,7 @@ Contents
* Use `Fault Handler`_ to detect and manage faults
* Add a higher frequency `Carrier`_, if output signals are passed through an isolation transformer
* Configuration and handling of `Interrupts`_.
* Extra configuration of `Resolution`_.
Configure
@@ -57,7 +58,8 @@ Configuration covers the following steps:
2. Initialization of two GPIOs as output signals within selected unit by calling :cpp:func:`mcpwm_gpio_init`. The two output signals are typically used to command the motor to rotate right or left. All available signal options are listed in :cpp:type:`mcpwm_io_signals_t`. To set more than a single pin at a time, use function :cpp:func:`mcpwm_set_pin` together with :cpp:type:`mcpwm_pin_config_t`.
3. Selection of a timer. There are three timers available within the unit. The timers are listed in :cpp:type:`mcpwm_timer_t`.
4. Setting of the timer frequency and initial duty within :cpp:type:`mcpwm_config_t` structure.
5. Calling of :cpp:func:`mcpwm_init` with the above parameters to make the configuration effective.
5. Setting timer resolution if necessary, by calling :cpp:func:`mcpwm_group_set_resolution` and :cpp:func:`mcpwm_timer_set_resolution`
6. Calling of :cpp:func:`mcpwm_init` with the above parameters to make the configuration effective.
Operate
@@ -159,6 +161,16 @@ Interrupts
Registering of the MCPWM interrupt handler is possible by calling :cpp:func:`mcpwm_isr_register`.
Resolution
----------
The default resolution for MCPWM group and MCPWM timer are configured to **10MHz** and **1MHz** in :cpp:func:`mcpwm_init`, which might be not enough for some applications.
The driver also provides two APIs that can be used to override the default resolution: :cpp:func:`mcpwm_group_set_resolution` and :cpp:func:`mcpwm_timer_set_resolution`.
Note that, these two APIs won't update the frequency and duty automatically, to achieve that, one has to call :cpp:func:`mcpwm_set_frequency` and :cpp:func:`mcpwm_set_duty` accordingly.
To get PWM pulse that is below 15Hz, please set the resolution to a lower value. For high frequency PWM with limited step range, please set them with higher value.
Application Example
-------------------