一、实验平台： 测试板：PCA10028 协议栈版本：nRF5_SDK_12.3.0_d7731ad 例程所在位置：nRF5_SDK_12.3.0_d7731adexamplesperipheralpwr_mgmt 官方解释：http://infocenter.nordicsemi.com/index.jsp 二、流程解释 根据官方的测试流程：按下BUTTON1后，进入bsp_evt_handler()的BSP_EVENT_KEY_0分支，将m_is_ready设置为true。
case BSP_EVENT_KEY_0: if (m_is_ready) { m_is_ready = false; NRF_LOG_INFO("System is not ready for shutdown "); } else { m_is_ready = true; NRF_LOG_INFO("System is ready for shutdown "); } if (m_sysoff_started && m_is_ready) { NRF_LOG_INFO("m_sysoff_started && m_is_ready is true "); nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_CONTINUE); } break;

在按BUTTON2，进入BSP_EVENT_SLEEP分支，因为m_stay_in_sysoff=false，执行nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF);函数。事件类型的定义是一个enmu。NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF=0。 case BSP_EVENT_SLEEP: if (m_stay_in_sysoff) { NRF_LOG_INFO("m_stay_in_sysoff is true "); nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_STAY_IN_SYSOFF); } else { NRF_LOG_INFO("m_stay_in_sysoff is false "); nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF); } break; nrf_pwr_mgmt_shutdown()函数内，将形参赋给m_pwr_mgmt_evt，之后执行shutdown_process();关机处理函数。
在shutdown_process();中执行if ((*PWR_MGMT_SECTION_VARS_GET(m_next_handler))(m_pwr_mgmt_evt))时会执行 执行关机回调函数，将事件类型做为参数传入。该回调函数是在main.c中注册的 bool app_shutdown_handler(nrf_pwr_mgmt_evt_t event); //lint -esym(528, m_app_shutdown_handler) NRF_PWR_MGMT_REGISTER_HANDLER(m_app_shutdown_handler) = app_shutdown_handler; 进入到bool app_shutdown_handler(nrf_pwr_mgmt_evt_t event) if (m_is_ready == false) { m_sysoff_started = true; NRF_LOG_INFO(" m_sysoff_started = true "); return false; } switch (event) { case NRF_PWR_MGMT_EVT_PREPARE_SYSOFF: NRF_LOG_INFO("NRF_PWR_MGMT_EVT_PREPARE_SYSOFF.. "); err_code = bsp_buttons_disable(); //关闭按键中断 睡眠之后无法唤醒 APP_ERROR_CHECK(err_code); break; case NRF_PWR_MGMT_EVT_PREPARE_WAKEUP: err_code = bsp_wakeup_button_enable(BTN_ID_WAKEUP); //设置按键唤醒 APP_ERROR_CHECK(err_code); NRF_LOG_INFO("NRF_PWR_MGMT_EVT_PREPARE_WAKEUP "); err_code = bsp_nfc_sleep_mode_prepare(); //设置NFCT为唤醒源 // Suppress NRF_ERROR_NOT_SUPPORTED return code. UNUSED_VARIABLE(err_code); break; case NRF_PWR_MGMT_EVT_PREPARE_DFU: NRF_LOG_ERROR("Entering DFU is not supported by this example. "); APP_ERROR_HANDLER(NRF_ERROR_API_NOT_IMPLEMENTED); break; } m_is_ready=true，进入NRF_PWR_MGMT_EVT_PREPARE_WAKEUP分支。

之后跳转到bool app_shutdown_handler(nrf_pwr_mgmt_evt_t event)回调函数中的NRF_PWR_MGMT_EVT_PREPARE_WAKEUP分支，首先执行bsp_wakeup_button_enable(BTN_ID_WAKEUP);设置按键唤醒 bsp_nfc_sleep_mode_prepare();设置NFCT为唤醒源
之后回到shutdown_process(); 最后执行NRF_POWER->SYSTEMOFF = POWER_SYSTEMOFF_SYSTEMOFF_Enter;执行休眠