Ledc randomly invert PWM signal output

[API-rep]

Board

ESP32 Dev module (Wroom-32)

Device Description

Wired on readboard

Hardware Configuration

RC servo / motor driver.

Version

v2.0.9

IDE Name

Arduino IDE

Operating System

Windows 10

Flash frequency

80Mhz

PSRAM enabled

yes

Upload speed

921600

Description

I'm working on a small library to drive DC and servo motor via ledc PWM output. To go deeper in timer management, I write it with ESP32 IDF regular syntax and structure. I've noticed that randomly, PWM output is inverted, regardless of the port use. I supposed a hardware trouble, but this problem happened with other ESP32 dev kit module.

Trouble was fixed by adding a _GPIO.func_out_sel_cfg[SERVO_PIN].inv_sel = 0_ on my code.

During my research to fix this problem, I noticed that the Espressif ESP32 IDF have a _outputinvert flag on its ledc_channel_config_t_ struct. I tried to implement it on my code, but Arduino ESP32 port seemed to miss this one and return me an error during compilation. I'm not a c expert programmer, but I suspect a non initialization of this variable by Arduino port who can cause this random problem ? Could you check that deeper in your code please.

Sketch

PWM setup code (cleaned for readability)

    // create timer config structure
_timers_config[_pwmTimer] = new ledc_timer_config_t;

    // seeding timer config parameters 
_timers_config[_pwmTimer]->speed_mode       = LEDC_HIGH_SPEED_MODE;     // set timer mode
_timers_config[_pwmTimer]->freq_hz      = pwmFreq;          // set frequency of PWM signal
_timers_config[_pwmTimer]->timer_num        = (ledc_timer_t)_pwmTimer;  // set timer index
_timers_config[_pwmTimer]->clk_cfg      = LEDC_AUTO_CLK;        // set LEDC source clock
_timers_config[_pwmTimer]->duty_resolution  = (ledc_timer_bit_t)resBit; // set duty resolution

    // create PWM channel config structure
ledc_channel_config = new ledc_channel_config_t;

    // seeding PWM channel config parameters 
_ledc_channel_config->channel       = (ledc_channel_t)_pwmChannel;
_ledc_channel_config->duty      = 0;
_ledc_channel_config->hpoint        = 0;
_ledc_channel_config->gpio_num      = pwmPin;
_ledc_channel_config->speed_mode    = LEDC_HIGH_SPEED_MODE;
_ledc_channel_config->timer_sel     = (ledc_timer_t)_pwmTimer;
_ledc_channel_config->intr_type     = LEDC_INTR_DISABLE;
// _ledc_channel_config->output_invert  = 0;    // don't work on Arduino ESP32 IDE

    // start PWM signal on pwmPin.
ledc_channel_config(_ledc_channel_config);  

    // set ledc fade service on for ledc_set_duty_and_update/ledc_set_fade_time_and_start functions
ledc_fade_func_install(0);

...
    // output duty to port
ledc_set_duty_and_update(LEDC_HIGH_SPEED_MODE, (ledc_channel_t)_pwmChannel, dutyToWrite, 0);

Debug Message

Error returned by compilator while output_invert struct flag is provided

error: 'struct ledc_channel_config_t' has no member named 'output_invert'
  _ledc_channel_config->output_invert = 0;
                        ^~~~~~~~~~~~~
exit status 1

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• [X] I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[me-no-dev]

Since you are using IDF API, I suggest you to file an issue in IDF's github repo. You can state that you are running ESP-IDF v4.4.4 with Arduino

[API-rep]

EDIT : Issue found. A (stupid) typo error. I forgot the flags. before the output_invert parrameter. All compile fine nox. You can safely close or delete the topic.