시중에 판매중인 모듈 사용하기

시중에 판매중인 nrf51822 모듈을 보면 2개의 크리스탈이 달려있습니다.

위 사진처럼 첫번째 모듈은 2개가 달려있는데 2번째와 4번째 모듈은 크리스탈이 하나만 달려있습니다. 

크리스탈이 하나이거나 크리스탈 값이 다르면 기본 예제 프로그램이 LED나 버튼 등은 동작하는데 BLE는 동작하지 않을것입니다.

이부분은 아래 처럼 수정하면 해결 가능합니다.

기본 예제인 ble_app_uart의 한 부분입니다.

/**@brief Function for the S110 SoftDevice initialization.
 *
 * @details This function initializes the S110 SoftDevice and the BLE event interrupt.
 */
static void ble_stack_init(void)
{
    uint32_t err_code;
    
    // Initialize SoftDevice.
    SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, NULL);
    // Enable BLE stack.
    ble_enable_params_t ble_enable_params;
    memset(&ble_enable_params, 0, sizeof(ble_enable_params));
#ifdef S130
    ble_enable_params.gatts_enable_params.attr_tab_size   = BLE_GATTS_ATTR_TAB_SIZE_DEFAULT;
#endif
    ble_enable_params.gatts_enable_params.service_changed = IS_SRVC_CHANGED_CHARACT_PRESENT;
    err_code = sd_ble_enable(&ble_enable_params);
    APP_ERROR_CHECK(err_code);
    
    // Subscribe for BLE events.
    err_code = softdevice_ble_evt_handler_set(ble_evt_dispatch);
    APP_ERROR_CHECK(err_code);
}

10번째 줄의 NRF_CLOCK_LFCLKSRC_XTAL_20_PPM 이부분을 자신에게 맞는 크리스탈로 변경해야 됩니다.

크리스탈이 달려있지 않다면 NRF_CLOCK_LFCLKSRC_RC_250_PPM_250MS_CALIBRATION로 변경하면 되고

달려있다면 크리스탈에 맞는 값으로 변경하면 됩니다.

코드 값은

nrf_sdm.h에 명시되어 있습니다.

/**@brief Possible lfclk oscillator sources. */
enum NRF_CLOCK_LFCLKSRCS
{
  NRF_CLOCK_LFCLKSRC_SYNTH_250_PPM,                       /**< LFCLK Synthesized from HFCLK.                    */
  NRF_CLOCK_LFCLKSRC_XTAL_500_PPM,                        /**< LFCLK crystal oscillator 500 PPM accuracy.       */
  NRF_CLOCK_LFCLKSRC_XTAL_250_PPM,                        /**< LFCLK crystal oscillator 250 PPM accuracy.       */
  NRF_CLOCK_LFCLKSRC_XTAL_150_PPM,                        /**< LFCLK crystal oscillator 150 PPM accuracy.       */
  NRF_CLOCK_LFCLKSRC_XTAL_100_PPM,                        /**< LFCLK crystal oscillator 100 PPM accuracy.       */
  NRF_CLOCK_LFCLKSRC_XTAL_75_PPM,                         /**< LFCLK crystal oscillator 75 PPM accuracy.        */
  NRF_CLOCK_LFCLKSRC_XTAL_50_PPM,                         /**< LFCLK crystal oscillator 50 PPM accuracy.        */
  NRF_CLOCK_LFCLKSRC_XTAL_30_PPM,                         /**< LFCLK crystal oscillator 30 PPM accuracy.        */
  NRF_CLOCK_LFCLKSRC_XTAL_20_PPM,                         /**< LFCLK crystal oscillator 20 PPM accuracy.        */
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_250MS_CALIBRATION,        /**< LFCLK RC oscillator, 250ms  calibration interval.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_500MS_CALIBRATION,        /**< LFCLK RC oscillator, 500ms  calibration interval.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_1000MS_CALIBRATION,       /**< LFCLK RC oscillator, 1000ms calibration interval.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_2000MS_CALIBRATION,       /**< LFCLK RC oscillator, 2000ms calibration interval.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_4000MS_CALIBRATION,       /**< LFCLK RC oscillator, 4000ms calibration interval.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_8000MS_CALIBRATION,       /**< LFCLK RC oscillator, 8000ms calibration interval.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_TEMP_1000MS_CALIBRATION,  /**< LFCLK RC oscillator. Temperature checked every 1000ms, if changed above a threshold, a calibration is done.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_TEMP_2000MS_CALIBRATION,  /**< LFCLK RC oscillator. Temperature checked every 2000ms, if changed above a threshold, a calibration is done.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_TEMP_4000MS_CALIBRATION,  /**< LFCLK RC oscillator. Temperature checked every 4000ms, if changed above a threshold, a calibration is done.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_TEMP_8000MS_CALIBRATION,  /**< LFCLK RC oscillator. Temperature checked every 8000ms, if changed above a threshold, a calibration is done.*/
  NRF_CLOCK_LFCLKSRC_RC_250_PPM_TEMP_16000MS_CALIBRATION, /**< LFCLK RC oscillator. Temperature checked every 16000ms, if changed above a threshold, a calibration is done.*/
};
 
/** @} */