Understanding demo1 in Nordic SDK PWM driver example code.

RE: Understanding demo1 in Nordic SDK PWM driver example code.

Edvin — Wed, 08 May 2019 09:30:38 GMT

[quote user="RyanA"]I want to set all 4 PWM channels to 4 different pins but don't understand how it is done currently through this code.[/quote]

In the pwm_library example?

Each PWM instance has two channels which pins are set in:

app_pwm_config_t pwm1_cfg = APP_PWM_DEFAULT_CONFIG_2CH(5000L, BSP_LED_0, BSP_LED_1);

BSP_LED_0 and BSP_LED_1 are the pins. If you want 4 channels, you must use two instances of PWM.

Then you have to actually initialize the PWM using app_pwm_init(), and then you can set the duty cycle using app_pwm_channel_duty_set(&PWM_instantce, channel_number, value);

So if you have two instances, PWM1 and PWM2, and each have two channels, and you want to set all channels to 50% duty cycle, you would have to do:

while(app_pwm_channel_duty_set(PWM1, 0, 50) == NRF_ERROR_BUSY);
while(app_pwm_channel_duty_set(PWM1, 1, 50) == NRF_ERROR_BUSY);
while(app_pwm_channel_duty_set(PWM2, 0, 50) == NRF_ERROR_BUSY);
while(app_pwm_channel_duty_set(PWM2, 1, 50) == NRF_ERROR_BUSY);

RE: Understanding demo1 in Nordic SDK PWM driver example code.

RyanA — Tue, 07 May 2019 15:42:07 GMT

Thanks, I will investigate this. I want to set all 4 PWM channels to 4 different pins but don't understand how it is done currently through this code.

RE: Understanding demo1 in Nordic SDK PWM driver example code.

Edvin — Mon, 06 May 2019 11:50:00 GMT

Hello,

So you "don't want any patterns or oscillations, is that correct?

So maybe something that could control a PWM motor, where you set one PWM duty cycle, which will stay until you set it again?

If that is the case, I suggest that you check out the pwm_library example instead. Although the LEDs flash, this is all done by a counter in the main()-loop, which continuously updates the duty cycles. If you comment this out, you can set the PWM duty cycles as you like.

Best regards,

Edvin