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。