NRF52832 SAADC定时器定时转换

1.在sdk_config.h中加入宏

// TIMER_ENABLED - nrf_drv_timer - TIMER periperal driver - legacy layer
//==========================================================
#ifndef TIMER_ENABLED
#define TIMER_ENABLED 1
#endif
// TIMER_DEFAULT_CONFIG_FREQUENCY  - Timer frequency if in Timer mode
 
// 16 MHz 
// 8 MHz 
// 4 MHz 
// 2 MHz 
// 1 MHz 
// 500 kHz 
// 250 kHz 
// 125 kHz 
// 62.5 kHz 
// 31.25 kHz 

#ifndef TIMER_DEFAULT_CONFIG_FREQUENCY
#define TIMER_DEFAULT_CONFIG_FREQUENCY 4
#endif

// TIMER_DEFAULT_CONFIG_MODE  - Timer mode or operation
 
// Timer 
// Counter 

#ifndef TIMER_DEFAULT_CONFIG_MODE
#define TIMER_DEFAULT_CONFIG_MODE 0
#endif

// TIMER_DEFAULT_CONFIG_BIT_WIDTH  - Timer counter bit width
 
// 16 bit 
// 8 bit 
// 24 bit 
// 32 bit 

#ifndef TIMER_DEFAULT_CONFIG_BIT_WIDTH
#define TIMER_DEFAULT_CONFIG_BIT_WIDTH 3
#endif

// TIMER_DEFAULT_CONFIG_IRQ_PRIORITY  - Interrupt priority
 

// Priorities 0,2 (nRF51) and 0,1,4,5 (nRF52) are reserved for SoftDevice
// 0 (highest) 
// 1 
// 2 
// 3 
// 4 
// 5 
// 6 
// 7 

#ifndef TIMER_DEFAULT_CONFIG_IRQ_PRIORITY
#define TIMER_DEFAULT_CONFIG_IRQ_PRIORITY 6
#endif

#ifndef TIMER0_ENABLED
#define TIMER0_ENABLED 1
#endif

// TIMER1_ENABLED  - Enable TIMER1 instance
 

#ifndef TIMER1_ENABLED
#define TIMER1_ENABLED 1
#endif

// TIMER2_ENABLED  - Enable TIMER2 instance
 

#ifndef TIMER2_ENABLED
#define TIMER2_ENABLED 1
#endif

// TIMER3_ENABLED  - Enable TIMER3 instance
 

#ifndef TIMER3_ENABLED
#define TIMER3_ENABLED 0
#endif

// TIMER4_ENABLED  - Enable TIMER4 instance
 

#ifndef TIMER4_ENABLED
#define TIMER4_ENABLED 0
#endif

// SAADC_ENABLED - nrf_drv_saadc - SAADC peripheral driver - legacy layer
//==========================================================
#ifndef SAADC_ENABLED
#define SAADC_ENABLED 1
#endif
// SAADC_CONFIG_RESOLUTION  - Resolution
 
// 8 bit 
// 10 bit 
// 12 bit 
// 14 bit 

#ifndef SAADC_CONFIG_RESOLUTION
#define SAADC_CONFIG_RESOLUTION 2
#endif

// SAADC_CONFIG_OVERSAMPLE  - Sample period
 
// Disabled 
// 2x 
// 4x 
// 8x 
// 16x 
// 32x 
// 64x 
// 128x 
// 256x 

#ifndef SAADC_CONFIG_OVERSAMPLE
#define SAADC_CONFIG_OVERSAMPLE 0
#endif

// SAADC_CONFIG_LP_MODE  - Enabling low power mode
 

#ifndef SAADC_CONFIG_LP_MODE
#define SAADC_CONFIG_LP_MODE 0
#endif

// SAADC_CONFIG_IRQ_PRIORITY  - Interrupt priority
 

// Priorities 0,2 (nRF51) and 0,1,4,5 (nRF52) are reserved for SoftDevice
// 0 (highest) 
// 1 
// 2 
// 3 
// 4 
// 5 
// 6 
// 7 

#ifndef SAADC_CONFIG_IRQ_PRIORITY
#define SAADC_CONFIG_IRQ_PRIORITY 6
#endif

2.导入文件nrfx_timer.c,nrfx_ssadc.c到工程中

3.引入头文件

#include "nrf_drv_timer.h"
#include "nrf_drv_saadc.h"

4.定义变量及宏

#define SAMPLES_IN_BUFFER 1
volatile uint8_t state = 1;

static const nrf_drv_timer_t m_timer = NRF_DRV_TIMER_INSTANCE(0);
static nrf_saadc_value_t     m_buffer_pool[2][SAMPLES_IN_BUFFER];
static nrf_ppi_channel_t     m_ppi_channel;
static uint32_t              m_adc_evt_counter;
5.事件处理函数

void timer_handler(nrf_timer_event_t event_type, void * p_context)
{
    ret_code_t err_code;
    switch(event_type)
    {
        case NRF_TIMER_EVENT_COMPARE0:
            err_code = nrfx_saadc_sample();
            APP_ERROR_CHECK(err_code);
            break;
        default:
            break;
    }
}

6.缓存池满处理函数

void saadc_callback(nrf_drv_saadc_evt_t const * p_event)
{
    if (p_event->type == NRF_DRV_SAADC_EVT_DONE)
    {
        ret_code_t err_code;

        err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAMPLES_IN_BUFFER);
        APP_ERROR_CHECK(err_code);

        int i;
        printf("\nADC event number: %d\n", (int)m_adc_evt_counter);

        for (i = 0; i < SAMPLES_IN_BUFFER; i++)
        {
            printf("%d", p_event->data.done.p_buffer[i]);
        }
        m_adc_evt_counter++;
    }
}

7.初时化函数

void saadc_init(void)
{
    ret_code_t err_code;
    nrf_saadc_channel_config_t channel_config =
        NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN7);

    err_code = nrf_drv_saadc_init(NULL, saadc_callback);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_saadc_channel_init(0, &channel_config);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0], SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1], SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);

}

void saadc_sampling_event_init(void)
{
    ret_code_t err_code;

  
    nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
    timer_cfg.bit_width = NRF_TIMER_BIT_WIDTH_32;
    err_code = nrf_drv_timer_init(&m_timer, &timer_cfg, timer_handler);
    APP_ERROR_CHECK(err_code);

    /* setup m_timer for compare event every 400ms */
    uint32_t ticks = nrf_drv_timer_ms_to_ticks(&m_timer, 1000);
    nrf_drv_timer_extended_compare(&m_timer,
                                   NRF_TIMER_CC_CHANNEL0,
                                   ticks,
                                   NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,
                                   true);
    nrf_drv_timer_enable(&m_timer);

}

8.在主函数中的处理

/**
 * @brief Function for main application entry.
 */
int main(void)
{
    uint32_t err_code;

    bsp_board_init(BSP_INIT_LEDS);

    const app_uart_comm_params_t comm_params =
      {
          RX_PIN_NUMBER,
          TX_PIN_NUMBER,
          RTS_PIN_NUMBER,
          CTS_PIN_NUMBER,
          UART_HWFC,
          false,
#if defined (UART_PRESENT)
          NRF_UART_BAUDRATE_115200
#else
          NRF_UARTE_BAUDRATE_115200
#endif
      };

    APP_UART_FIFO_INIT(&comm_params,
                         UART_RX_BUF_SIZE,
                         UART_TX_BUF_SIZE,
                         uart_error_handle,
                         APP_IRQ_PRIORITY_LOWEST,
                         err_code);

    APP_ERROR_CHECK(err_code);

    saadc_init();
    saadc_sampling_event_init();
  
    while (true)
    {
      
        
    }

}