Pwm minimum frequency setting

RE: Pwm minimum frequency setting

Sigurd — Wed, 24 May 2017 12:43:12 GMT

Could it be a timeout from the WDT that is causing the issues?

See this post about how to debug and find the reason for the reset.

RE: Pwm minimum frequency setting

muyang — Wed, 24 May 2017 11:40:18 GMT

Through repeated tests, I found the problem is that when I only set a pin of duty, it is working properly, but the two set at the same time duty, the program stuck, and then reset

uint8_t Motor_Duty_Set(uint32_t DutyLeft,uint32_t DutyRight)

{ uint8_t TimeOut = 0; //wdt_feed(); while (app_pwm_channel_duty_set(&PWM1,(uint8_t) 0, DutyLeft) == NRF_ERROR_BUSY) { wdt_feed(); #if 0 if(TimeOut ++ > 200) { TimeOut = 0; return 0; } #endif }

wdt_feed();
#if 0
while (app_pwm_channel_duty_set(&PWM1,(uint8_t) 1, DutyRight) == NRF_ERROR_BUSY)
{
	#if 0
	if(TimeOut ++ > 200)
	{
		TimeOut = 0;
		return 0;	
	}	
	#endif
}
#endif
//wdt_feed();
//return 1;

}

So that you can work and output the correct 1hz waveform, should I only open the left, the right side of the code shielded

But when I try to set the duty cycle of both channels, the device is reset, the code is as follows

uint8_t Motor_Duty_Set(uint32_t DutyLeft,uint32_t DutyRight)

{ uint8_t TimeOut = 0; //wdt_feed(); while (app_pwm_channel_duty_set(&PWM1,(uint8_t) 0, DutyLeft) == NRF_ERROR_BUSY) { wdt_feed(); #if 0 if(TimeOut ++ > 200) { TimeOut = 0; return 0; } #endif }

wdt_feed();
#if 1
while (app_pwm_channel_duty_set(&PWM1,(uint8_t) 1, DutyRight) == NRF_ERROR_BUSY)
{
	#if 0
	if(TimeOut ++ > 200)
	{
		TimeOut = 0;
		return 0;	
	}	
	#endif
}
#endif
//wdt_feed();
//return 1;

}

enter code here

RE: Pwm minimum frequency setting

Sigurd — Wed, 24 May 2017 11:13:29 GMT

I used the pwm_library example in the SDK. This is the main.c code I used:

#include <stdbool.h>
#include <stdint.h>
#include "nrf.h"
#include "app_error.h"
#include "bsp.h"
#include "nrf_delay.h"
#include "app_pwm.h"

APP_PWM_INSTANCE(PWM1,1);                   // Create the instance "PWM1" using TIMER1.


 void Motor_Pwm_Init(uint32_t freq,uint32_t MotorLeft_Polarity,uint32_t MotorRight_Polarity)
{

    uint32_t err_code;

    app_pwm_disable(&PWM1);
    app_pwm_uninit(&PWM1);
    app_pwm_config_t pwm1_cfg = APP_PWM_DEFAULT_CONFIG_2CH(freq,3,4);   //set pwm frequency  

    pwm1_cfg.pin_polarity[0] = MotorLeft_Polarity;                  //Polarity of active state on pin.
    pwm1_cfg.pin_polarity[1] = MotorRight_Polarity;

    err_code = app_pwm_init(&PWM1,&pwm1_cfg,NULL);           //  Init the PWM
    APP_ERROR_CHECK(err_code);

    app_pwm_enable(&PWM1);  

}

uint8_t Motor_Duty_Set(uint32_t DutyLeft,uint32_t DutyRight)
{
    uint8_t TimeOut = 0;
    //wdt_feed();
    while (app_pwm_channel_duty_set(&PWM1,(uint8_t) 0, DutyLeft) == NRF_ERROR_BUSY)
    {

    }
    
    while (app_pwm_channel_duty_set(&PWM1,(uint8_t) 1, DutyLeft) == NRF_ERROR_BUSY)
    {

    }
}

int main(void)
{
    
    Motor_Pwm_Init(1000000,1,1);
    Motor_Duty_Set(50,50);
    
    while (true)
    {

    }

}


/** @} */

RE: Pwm minimum frequency setting

muyang — Wed, 24 May 2017 11:11:20 GMT

Can you send me your project

RE: Pwm minimum frequency setting

muyang — Wed, 24 May 2017 11:09:51 GMT

Freq this parameter you fill how much? I really can not run here when the 1HZ

RE: Pwm minimum frequency setting

Sigurd — Wed, 24 May 2017 10:58:05 GMT

Hi,

I get 1 Hz with the code you posted. Note that you will only get 1 Hz on the MOTOR_LEFT_PIN since you are only setting the duty cycle to 50% on that pin/channel.

You can modify the Motor_Duty_Set() function to also set the duty cycle for the MOTOT_RIGHT_PIN pin/channel like this:

uint8_t Motor_Duty_Set(uint32_t DutyLeft,uint32_t DutyRight)
{
    uint8_t TimeOut = 0;
    wdt_feed();
    while (app_pwm_channel_duty_set(&PWM1,(uint8_t) 0, DutyLeft) == NRF_ERROR_BUSY)
    {

    }

    while (app_pwm_channel_duty_set(&PWM1,(uint8_t) 1, DutyLeft) == NRF_ERROR_BUSY)
    {

    }

}

RE: Pwm minimum frequency setting

muyang — Wed, 24 May 2017 03:30:47 GMT

I want to output 1HZ what should i do?

RE: Pwm minimum frequency setting

muyang — Wed, 24 May 2017 03:17:01 GMT

I have been tested to find the minimum frequency can be set to 4HZ, I would like to change with a small time found 51822 reset