野火freertos内核实现与应用开发实战指南3课件第19节

软件定时器FreeRTOS内核实现与应用开发实战指南淘宝：论坛：扫描进入淘宝店铺01软件定时器启动02软件定时器任务03实验参考资料:《FreeRTOS内核实现与应用开发实战指南》主讲内容软件定时器启动xTimerStart()xTimerStartFromISR()本质：通过“定时器命令队列”向定时器任务发送一个启动命令。#define xTimerStart(xTimer,xTicksToWait) xTimerGenericCommand((xTimer),

tmrCOMMAND_START, (xTaskGetTickCount()), NULL,(xTicksToWait))#define xTimerStartFromISR(xTimer,pxHigherPriorityTaskWoken) xTimerGenericCommand((xTimer),

tmrCOMMAND_START_FROM_ISR, (xTaskGetTickCountFromISR()), (pxHigherPriorityTaskWoken),0U)软件定时器停止xTimerStop()xTimerStopFromISR()通过“定时器命令队列”发送一个停止命令给软件定时器任务。#define xTimerStop(xTimer,xTicksToWait) xTimerGenericCommand((xTimer),

tmrCOMMAND_STOP, 0U,NULL,(xTicksToWait))#define xTimerStopFromISR(xTimer,pxHigherPriorityTaskWoken) xTimerGenericCommand((xTimer),

tmrCOMMAND_STOP_FROM_ISR, 0,(pxHigherPriorityTaskWoken),0U)

软件定时器删除#define xTimerDelete(xTimer,xTicksToWait) xTimerGenericCommand((xTimer), tmrCOMMAND_DELETE, 0U,NULL,(xTicksToWait))软件定时器任务vTaskStartScheduler()->xTimerCreateTimerTask()->xTaskCreate()prvTimerTask()优先级#defineconfigTIMER_TASK_PRIORITY

(configMAX_PRIORITIES-1)定时器任务处理prvGetNextExpireTime()prvProcessTimerOrBlockTask()->prvSampleTimeNow()prvProcessReceivedCommands()软件定时器实验软件定时器实验是在FreeRTOS中创建了两个软件定时器，其中一个软件定时器是单次模式，5000个tick调用一次回调函数，另一个软件定时器是周期模式，1000个tick调用一次回调函数。步骤：定义软件定时器句柄实现回调函数void(*TimerCallbackFunction_t)(TimerHandle_txTimer);创建定时器——xTi