NRF51822之使用外部32Mhz晶振

硬件平台为微雪BLE400的(将原来的16mhz晶振改为32mhz。两个旁电容改为22pf)

以nRF51_SDK_10.0.0_dc26b5e\examples\ble_peripheral\ble_app_uart项目为例

在main.c中进行修改

#if defined( USB_SYSTEM_CLOCK_32MHZ)

#define DEVICE_NAME                     "Nordic_UART_32mhz"                               /**< Name of device. Will be included in the advertising data. */

#else

#define DEVICE_NAME                     "Nordic_UART"                               /**< Name of device. Will be included in the advertising data. */

#endif//USB_SYSTEM_CLOCK_32MHZ

#if defined (USB_SYSTEM_CLOCK_32MHZ)

/**@brief Function for Set the external high frequency clock source to 32 MHz .

 */

static void setClock( void )

{

    // Set the external high frequency clock source to 32 MHz

    NRF_CLOCK->XTALFREQ = 0xFFFFFF00;

    // Start the external high frequency crystal

    NRF_CLOCK->EVENTS_HFCLKSTARTED = ;

    NRF_CLOCK->TASKS_HFCLKSTART = ;

    // Wait for the external oscillator to start up

    while (NRF_CLOCK->EVENTS_HFCLKSTARTED == ) {}

}

#endif//USB_SYSTEM_CLOCK_32MHZ

/**@brief Application main function.

 */

int main(void)

{

    uint32_t err_code;

    bool erase_bonds;

    uint8_t  start_string[] = START_STRING;

  #if defined (USB_SYSTEM_CLOCK_32MHZ)

    setClock();

  #endif//USB_SYSTEM_CLOCK_32MHZ

    // Initialize.

    APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_OP_QUEUE_SIZE, false);

    uart_init();

    buttons_leds_init(&erase_bonds);

    ble_stack_init();

    gap_params_init();

    services_init();

    advertising_init();

    conn_params_init();

    printf("%s",start_string);

    err_code = ble_advertising_start(BLE_ADV_MODE_FAST);

    APP_ERROR_CHECK(err_code);

    // Enter main loop.

    for (;;)

    {

        power_manage();

    }

}

修改system_nrf51.C

#if defined( USB_SYSTEM_CLOCK_32MHZ)

#define __SYSTEM_CLOCK      (32000000UL)     /*!< nRF51 devices use a fixed System Clock Frequency of 32MHz */

#else

#define __SYSTEM_CLOCK      (16000000UL)     /*!< nRF51 devices use a fixed System Clock Frequency of 16MHz */

#endif//USB_SYSTEM_CLOCK_32MHZ

后面的测试的步骤和16mhz步骤相同。