关于BLEevents和system(SOC) events的区别

在51822这个芯片的协议栈初始化函数ble_stack_init里的ble_evt_dispatch和sys_evt_dispatch这两个函数注册了这两个事件的回调函数，代码如下：
/**@brief Function for initializing the BLE stack.
*
* @Details Initializes the SoftDevice and the BLE event interrupt.
*/
static void ble_stack_init(void)
{
uint32_t err_code;

// Initialize the SoftDevice handler module.
SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, false);

// Register with the SoftDevice handler module for BLE events.
err_code = softdevice_ble_evt_handler_set(ble_evt_dispatch);
APP_ERROR_CHECK(err_code);

// Register with the SoftDevice handler module for BLE events.
err_code = softdevice_sys_evt_handler_set(sys_evt_dispatch);
APP_ERROR_CHECK(err_code);
}
先看softdevice_sys_evt_handler_set系统回调函数：
uint32_t softdevice_sys_evt_handler_set(sys_evt_handler_t sys_evt_handler)
{
if (sys_evt_handler == NULL)
{
      return NRF_ERROR_NULL;
}

m_sys_evt_handler = sys_evt_handler;

return NRF_SUCCESS;
}
这里就是初始化m_sys_evt_handler变量，该变量在intern_softdevice_events_execute这个函数使用，代码如下：
void intern_softdevice_events_execute(void)
{
if (!m_softdevice_enabled)
{
      // SoftDevice not enabled. This can be possible if the SoftDevice was enabled by the
      // application without using this module's API (i.e softdevice_handler_init)

      return;
}

bool no_more_soc_evts = (m_sys_evt_handler == NULL);
#ifdef BLE_STACK_SUPPORT_REQD
bool no_more_ble_evts = (m_ble_evt_handler == NULL);
#endif
#ifdef ANT_STACK_SUPPORT_REQD
bool no_more_ant_evts = (m_ant_evt_handler == NULL);
#endif

for (;;)
{
      uint32_t err_code;

      if (!no_more_soc_evts)
      {
         uint32_t evt_id;

         // Pull event from SOC.
         err_code = sd_evt_get(&evt_id);

         if (err_code == NRF_ERROR_NOT_FOUND)
         {
            no_more_soc_evts = true;
         }
         else if (err_code != NRF_SUCCESS)
         {
            APP_ERROR_HANDLER(err_code);
         }
         else
         {
            // Call application's SOC event handler.
            m_sys_evt_handler(evt_id);
         }
      }

#ifdef BLE_STACK_SUPPORT_REQD
      // Fetch BLE Events.
      if (!no_more_ble_evts)
      {
         // Pull event from stack
         uint16_t evt_len = m_ble_evt_buffer_size;

         err_code = sd_ble_evt_get(m_evt_buffer, &evt_len);
         if (err_code == NRF_ERROR_NOT_FOUND)
         {
            no_more_ble_evts = true;
         }
         else if (err_code != NRF_SUCCESS)
         {
            APP_ERROR_HANDLER(err_code);
         }
         else
         {
            // Call application's BLE stack event handler.
            m_ble_evt_handler((ble_evt_t *)m_evt_buffer);
         }
      }
#endif

#ifdef ANT_STACK_SUPPORT_REQD
      // Fetch ANT Events.
      if (!no_more_ant_evts)
      {
         // Pull event from stack
         err_code = sd_ant_event_get(&((ant_evt_t *)m_evt_buffer)->channel,
                                    &((ant_evt_t *)m_evt_buffer)->event,
                                    ((ant_evt_t *)m_evt_buffer)->evt_buffer);
         if (err_code == NRF_ERROR_NOT_FOUND)
         {
            no_more_ant_evts = true;
         }
         else if (err_code != NRF_SUCCESS)
         {
            APP_ERROR_HANDLER(err_code);
         }
         else
         {
            // Call application's ANT stack event handler.
            m_ant_evt_handler((ant_evt_t *)m_evt_buffer);
         }
      }
#endif

      if (no_more_soc_evts)
      {
         // There are no remaining System (SOC) events to be fetched from the SoftDevice.
#if defined(ANT_STACK_SUPPORT_REQD) && defined(BLE_STACK_SUPPORT_REQD)
         // Check if there are any remaining BLE and ANT events.
         if (no_more_ble_evts && no_more_ant_evts)
         {
            break;
         }
#elif defined(BLE_STACK_SUPPORT_REQD)
         // Check if there are any remaining BLE events.
         if (no_more_ble_evts)
         {
            break;
         }
#elif defined(ANT_STACK_SUPPORT_REQD)
         // Check if there are any remaining ANT events.
         if (no_more_ant_evts)
         {
            break;
         }
#else
         // No need to check for BLE or ANT events since there is no support for BLE and ANT
         // required.
         break;
#endif
      }
}
}
对于系统时间的关键代码是这样的：
      if (!no_more_soc_evts)
      {
         uint32_t evt_id;

         // Pull event from SOC.
         err_code = sd_evt_get(&evt_id);

         if (err_code == NRF_ERROR_NOT_FOUND)
         {
            no_more_soc_evts = true;
         }
         else if (err_code != NRF_SUCCESS)
         {
            APP_ERROR_HANDLER(err_code);
         }
         else
         {
            // Call application's SOC event handler.
            m_sys_evt_handler(evt_id);
         }
类似的对于BLE时间的关键代码如下：
      if (!no_more_ble_evts)
      {
         // Pull event from stack
         uint16_t evt_len = m_ble_evt_buffer_size;

         err_code = sd_ble_evt_get(m_evt_buffer, &evt_len);
         if (err_code == NRF_ERROR_NOT_FOUND)
         {
            no_more_ble_evts = true;
         }
         else if (err_code != NRF_SUCCESS)
         {
            APP_ERROR_HANDLER(err_code);
         }
         else
         {
            // Call application's BLE stack event handler.
            m_ble_evt_handler((ble_evt_t *)m_evt_buffer);
         }
      }
那么他们的不同就在于sd_evt_get和sd_ble_evt_get，在手册中对sd_evt_get解释如下：

uint32_t sd_evt_get

(

uint32_t *

p_evt_id

)

Gets any pending events generated by the SoC API.
The application should keep calling this function to get events, until NRF_ERROR_NOT_FOUND is returned.
Parameters

[out]

p_evt_id

Set to one of the values in NRF_SOC_EVTS, if any events are pending.

Return values

NRF_SUCCESS	An event was pending. The event id is written in the p_evt_id parameter.
NRF_ERROR_NOT_FOUND	No pending events.

有这个提示再看看SoC API：
FunctionsSoC Library API

Functions
uint32_t	sd_mutex_new (nrf_mutex_t *p_mutex)
	Initialize a mutex. More...

uint32_t	sd_mutex_acquire (nrf_mutex_t *p_mutex)
	Attempt to acquire a mutex. More...

uint32_t	sd_mutex_release (nrf_mutex_t *p_mutex)
	Release a mutex. More...

uint32_t	sd_nvic_EnableIRQ (IRQn_Type IRQn)
	Enable External Interrupt. More...

uint32_t	sd_nvic_DisableIRQ (IRQn_Type IRQn)
	Disable External Interrupt. More...

uint32_t	sd_nvic_GetPendingIRQ (IRQn_Type IRQn, uint32_t *p_pending_irq)
	Get Pending Interrupt. More...

uint32_t	sd_nvic_SetPendingIRQ (IRQn_Type IRQn)
	Set Pending Interrupt. More...

uint32_t	sd_nvic_ClearPendingIRQ (IRQn_Type IRQn)
	Clear Pending Interrupt. More...

uint32_t	sd_nvic_SetPriority (IRQn_Type IRQn,nrf_app_irq_priority_t priority)
	Set Interrupt Priority. More...

uint32_t	sd_nvic_GetPriority (IRQn_Type IRQn,nrf_app_irq_priority_t *p_priority)
	Get Interrupt Priority. More...

uint32_t	sd_nvic_SystemReset (void)
	System Reset. More...

uint32_t	sd_nvic_critical_region_enter (uint8_t *p_is_nested_critical_region)
	Enters critical region. More...

uint32_t	sd_nvic_critical_region_exit (uint8_t is_nested_critical_region)
	Exit critical region. More...

uint32_t	sd_rand_application_pool_capacity_get (uint8_t *p_pool_capacity)
	Query the capacity of the application random pool. More...

uint32_t	sd_rand_application_bytes_available_get (uint8_t *p_bytes_available)
	Get number of random bytes available to the application. More...

uint32_t	sd_rand_application_vector_get (uint8_t *p_buff, uint8_t length)
	Get random bytes from the application pool. More...

uint32_t	sd_power_reset_reason_get (uint32_t *p_reset_reason)
	Gets the reset reason register. More...

uint32_t	sd_power_reset_reason_clr (uint32_t reset_reason_clr_msk)
	Clears the bits of the reset reason register. More...

uint32_t	sd_power_mode_set (nrf_power_mode_t power_mode)
	Sets the power mode when in CPU sleep. More...

uint32_t	sd_power_system_off (void)