how do I change PWM port to 1 on example "low_power_pwm"

RE: how do I change PWM port to 1 on example "low_power_pwm"

Shahar — Mon, 12 Oct 2020 07:58:57 GMT

The issue still exists in SDK 17.0.0 and SDK 17.0.2

Can someone from Nordic please add this to the next SDK releases?

RE: how do I change PWM port to 1 on example "low_power_pwm"

Igor — Wed, 13 May 2020 15:11:06 GMT

NRF SDK 16.0.0 also has an issue with low power PWM on port 1.

low_power_pwm.c, line 188 should be changed from

 nrf_gpio_cfg_output(pin_number);

 nrf_gpio_cfg_output(NRF_GPIO_PIN_MAP(p_pwm_instance->p_port==NRF_P1,pin_number));

Proper usage is then:

#define LED_1          NRF_GPIO_PIN_MAP(1,14) // port 1, pin 14

low_power_pwm_config_t pwm_config;
pwm_config.active_high = LEDS_ACTIVE_STATE;
pwm_config.bit_mask =PIN_MASK(LED_1);
pwm_config.p_port = PIN_PORT(LED_1);

P.S. There is another Low Power issue present in SDK 16.0.0 https://devzone.nordicsemi.com/f/nordic-q-a/29076/low_power_pwm-duty_cycle-seems-buggy https://devzone.nordicsemi.com/f/nordic-q-a/29076/low_power_pwm-duty_cycle-seems-buggy

RE: how do I change PWM port to 1 on example "low_power_pwm"

Herb W. — Mon, 26 Jun 2017 12:31:08 GMT

Thank you Kristin,

I it was the Direction not getting set that I missed.

RE: how do I change PWM port to 1 on example "low_power_pwm"

FormerMember — Thu, 22 Jun 2017 07:56:23 GMT

To get the correct pin numbers for pin P1.x, you can use ´NRF_GPIO_PIN_MAP()´in nrf_gpio.h.

For example, pin P1.08:

#define PIN_D7    NRF_GPIO_PIN_MAP(1,8)

By porting P1.8 this way, the value of PIN_D7 is 40 (32+8).

However, low_power_pwm_init() requires a bit mask, which is a uint32_t. In that case, P1.08 is pin 8 on port 1:

low_power_pwm_config.bit_mask       = (1 <<  NRF_GPIO_PIN_MAP(0,8)); 
low_power_pwm_config.p_port         = NRF_P1;

In low_power_pwm_init(), when configuring the output pin(s), the port is not taken care of. Therefore, to make the pwm driver work with port 1 pins, nrf_gpio_port_dir_output_set() has to be used to configure the pin in low_power_pwm_init():

 nrf_gpio_port_dir_output_set(p_pwm_config->p_port,p_pwm_instance->bit_mask); //todo
    //while (bit_mask)
    //{
    //    if (bit_mask & 0x1UL)
    //    {
    //        //nrf_gpio_cfg_output(pin_number);
    //    }
    //
    //    pin_number++;
    //    bit_mask >>= 1UL;
    //}