Init more than one PWM

[Inspectron]

I would like to use 3 PWM for controling RGBs. I use a softdevice because I want to control the pwm trough the MCP. But for now I just want to get it work to initialize these 3 pwms.

If I init one PWM everything works. When I try to init a second PWM, the first pwm will also not work.

Here the Init for the 2 PWMs:

static volatile bool ready_flag0;
static volatile bool ready_flag1;

APP_PWM_INSTANCE(PWM0,0);
APP_PWM_INSTANCE(PWM1,1);

static void pwm0_ready_callback(uint32_t pwm0_id)
{
    ready_flag0 = true;
}

static void pwm1_ready_callback(uint32_t pwm1_id)
{
    ready_flag1 = true;
}

static void PWMinit(void)
{
    app_pwm_config_t pwm0_cfg = APP_PWM_DEFAULT_CONFIG_1CH(2000000,22);
    pwm0_cfg.pin_polarity[0]	= APP_PWM_POLARITY_ACTIVE_HIGH;
    app_pwm_init(&PWM0,&pwm0_cfg,pwm0_ready_callback);

    app_pwm_config_t pwm1_cfg = APP_PWM_DEFAULT_CONFIG_1CH(1000000, 23);
    pwm1_cfg.pin_polarity[0]	= APP_PWM_POLARITY_ACTIVE_HIGH;
    app_pwm_init(&PWM1,&pwm1_cfg,pwm1_ready_callback);
}

static void PWMstart(uint8_t pwm_number)
{
    switch(pwm_number)
    {
	    case 0:			nrf_drv_gpiote_out_task_enable(22);
							app_pwm_enable(&PWM0);
							while (app_pwm_channel_duty_set(&PWM0, 0, 50) == NRF_ERROR_BUSY);
							break;
	
	    case 1:			nrf_drv_gpiote_out_task_enable(23);
							app_pwm_enable(&PWM1);
							while (app_pwm_channel_duty_set(&PWM1, 0, 50) == NRF_ERROR_BUSY);
							break;
    }
}

And in the main:

PWMinit();
PWMstart(0);
PWMstart(1);

What is wrong with the initialization for the second pwm?

[Krzysztof Chruscinski]

Hi,

some hints:

• TIMER0 is used by SoftDevice so it will generate conflict creating instance using TIMER0 (APP_PWM_INSTANCE(PWM0,0);),
• nrf_drv_gpiote_out_task_enable(x); calls are redundant.
• would be good to check return value of app_pwm_init()

However, I don't know yet how it can give the behavior you've described.

[Inspectron]

Oh yes I can remember that I read something about that(SoftDevice uses TIMER0). Now I have 2 PWMs working. But is it possible to have 3 PWMs with different Duty cycles? I'm asking because there are no more TIMERs free. So how I can set up the third PWM signal?

[Krzysztof Chruscinski]

With SoftDevice probably not. There is also a limitation in GPIOTE channels since there are 4 so you can have only up to 4 outputs. In that case, you can have 2 PWMs with 2 independent channels (they will have same period but different duty cycle).

[Inspectron]

Oh well, this are good news. I could set up 2 Timers (TIMER1 with one channel and TIMER2 with 2 channels) but with the same period. And over MCP control the duty cycle of each channel. Thank you for the support ;)