Access the led_state value in the blinky app example, for using it in the main function !

[abdelali]

hi ,

new to Nordic developmen. struggling to access the characteristic data to be able to use it in the main function !

i have started with the blinky app example as it covers my needs for the ble setting (need one service + 2 characteristics ) . for my project i need to use the characteristic data (the  led_state  in the example ) in my main function .

but the led_state data seems to be not accessible at this function !  have tried the memcpy() , can't copy it .

please kindly guide .

static void led_write_handler(uint16_t conn_handle, ble_lbs_t * p_lbs, uint8_t led_state)
{
          
if(led_state){
        bsp_board_led_on(BSP_BOARD_LED_0);
        NRF_LOG_INFO("Received LED ON!");
    }
    else
    {
        bsp_board_led_off(BSP_BOARD_LED_0);
        NRF_LOG_INFO("Received LED OFF!");
    }

}

[Marjeris Romero]

Hi,

"led_state" is a variable that only exists inside led_write_handler() and you cannot use it outside of this function.

What you can do is to create a static variable outside of the function to store the LED status information and then use this variable in main().

For example:

static uint8_t m_led_state; 

static void led_write_handler(uint16_t conn_handle, ble_lbs_t * p_lbs, uint8_t led_state)
{
    m_led_state = led_state;
    if (led_state)
    {
        bsp_board_led_on(LEDBUTTON_LED);
        NRF_LOG_INFO("Received LED ON!");
    }
    else
    {
        bsp_board_led_off(LEDBUTTON_LED);
        NRF_LOG_INFO("Received LED OFF!");
    } 

[abdelali]

hi,

thanks for your reply Marjeris Romero !

i have merged the pwm driver example with the blinky example to be able to control the PWM duty cycle via an application on my phone . 

i can control the pwm's duty cycle from the app , but the control seems to be dellayed ! when the ducty cycle goes up , it is kind on working , but when it goes down the control seems to take lot of time .

i use a slider in the app for controlling the duty cycle , the app will keep writing new values to the led characteristic when ever the slider value updated .

this is the pwm example i used . so basicaly i just copy the led_sate variable from the led_write_handler() an passe it to the pwm_update_duty_cycle() function . 

i have enabled the required settings in the sdk_config file for the PWM , it is working fine . the example work as expected !

the issue where just when we add the ble control .

#include <stdio.h>
#include <string.h>
#include "nrf_drv_pwm.h"
#include "app_util_platform.h"
#include "app_error.h"
#include "boards.h"
#include "bsp.h"
#include "nrf_drv_clock.h"
#include "nrf_delay.h"


#define OUTPUT_PIN LED_1

static nrf_drv_pwm_t m_pwm0 = NRF_DRV_PWM_INSTANCE(0);

// Declare variables holding PWM sequence values. In this example only one channel is used 
nrf_pwm_values_individual_t seq_values[] = {0, 0, 0, 0};
nrf_pwm_sequence_t const seq =
{
    .values.p_individual = seq_values,
    .length          = NRF_PWM_VALUES_LENGTH(seq_values),
    .repeats         = 0,
    .end_delay       = 0
};


// Set duty cycle between 0 and 100%
void pwm_update_duty_cycle(uint8_t duty_cycle)
{
    
    // Check if value is outside of range. If so, set to 100%
    if(duty_cycle >= 100)
    {
        seq_values->channel_0 = 100;
    }
    else
    {
        seq_values->channel_0 = duty_cycle;
    }
    
    nrf_drv_pwm_simple_playback(&m_pwm0, &seq, 1, NRF_DRV_PWM_FLAG_LOOP);
}

static void pwm_init(void)
{
    nrf_drv_pwm_config_t const config0 =
    {
        .output_pins =
        {
            OUTPUT_PIN, // channel 0
            NRF_DRV_PWM_PIN_NOT_USED,             // channel 1
            NRF_DRV_PWM_PIN_NOT_USED,             // channel 2
            NRF_DRV_PWM_PIN_NOT_USED,             // channel 3
        },
        .irq_priority = APP_IRQ_PRIORITY_LOWEST,
        .base_clock   = NRF_PWM_CLK_1MHz,
        .count_mode   = NRF_PWM_MODE_UP,
        .top_value    = 100,
        .load_mode    = NRF_PWM_LOAD_INDIVIDUAL,
        .step_mode    = NRF_PWM_STEP_AUTO
    };
    // Init PWM without error handler
    APP_ERROR_CHECK(nrf_drv_pwm_init(&m_pwm0, &config0, NULL));
    
}


int main(void)
{

    // Start clock for accurate frequencies
    NRF_CLOCK->TASKS_HFCLKSTART = 1; 
    // Wait for clock to start
    while(NRF_CLOCK->EVENTS_HFCLKSTARTED == 0) 
        ;
    
    pwm_init();

    for (;;)
    {
        for(int i = 0; i <= 100; i++)
        {
            pwm_update_duty_cycle(i);
        }
    }
}

[Marjeris Romero]

Hi,

Can you attach the code where you use PWM+BLE?

Best regards,

Marjeris