how to define gpio pins and generate pwm on gpio pins?

[ASHISH]

Hi There, i am new to nrf51822 and new to program this kind of controller.I searched over the website, I couldn't find a good introductory documentation for programming the nrf51822, specifically the nrf51-dk. i have two problems 1.i want to connect a led and buzzer to gpio pins of nrf51822 so how to declare gpio pins in program for ex. suppose if i press button on nrf board the buzzer connected to gpio pins (for (ex. p0.0) should be on (make some sound). 2.i want to generate a pwm on gpio pin (for ex on p0.1) how to declare this pin as output for pwm how to use functions to declare gpio,led and other stuff as i gone through the tutorial it is not well defined and the tutorials are very much confused and easy to understandable can anybody give me the good explnation about this a good tutorial with each and every line explained will be great help!! Regards, Abhijeet Kapse

[Sigurd]

Hi,

As an introduction, I would recommend the Getting Started guide and our examples in the SDK. For PWM generation on the nRF51, you should take a look at the PWM library example. You can find the example in the folder: <SDK_InstallFolder>\examples\peripheral\pwm_library

[Sigurd]

Try something like this:

/** @file
 * @defgroup pwm_example_main main.c
 * @{
 * @ingroup pwm_example
 *
 * @brief  PWM Example Application main file.
 *
 * This file contains the source code for a sample application using PWM.
 *
 *
 */

#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.

static volatile bool ready_flag;            // A flag indicating PWM status.

void pwm_ready_callback(uint32_t pwm_id)    // PWM callback function
{
    ready_flag = true;
}

int main(void)
{
    ret_code_t err_code;

    /* 1-channel PWM, 100000 microseconds period = 0.1 second , output on pin 4. */
    app_pwm_config_t pwm1_cfg = APP_PWM_DEFAULT_CONFIG_1CH(100000L, 4);

    /* Switch the polarity of the second channel. */
    pwm1_cfg.pin_polarity[1] = APP_PWM_POLARITY_ACTIVE_HIGH;

    /* Initialize and enable PWM. */
    err_code = app_pwm_init(&PWM1,&pwm1_cfg,pwm_ready_callback);
    APP_ERROR_CHECK(err_code);
    app_pwm_enable(&PWM1);
    
    //DUTY CYCLE SET TO 50%
    while (app_pwm_channel_duty_set(&PWM1, 0, 50) == NRF_ERROR_BUSY);

   
    while (true)
    {
            // Use directly __WFE and __SEV macros since the SoftDevice is not available.

    // Wait for event.
    __WFE();

    // Clear Event Register.
    __SEV();
    __WFE();

    }

}


/** @} */