【AT-START-L021测评】FREERTOS之互斥信号量
代码：#include "at32l021_board.h"
#include "at32l021_clock.h"
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "semphr.h"
#include "stdio.h"
/** @addtogroup UTILITIES_examples
* @{
*/
int cnt=0;
SemaphoreHandle_t MutexSemaphore;
/** @addtogroup FreeRTOS_demo
* @{
*/
//unsigned char const mainSENDER_1=30;
//unsigned char const mainSENDER_2=50;
button_type at32_button_press(void);
void task1(void *pvParameters)
{
static uint32_t times;
while(1)
{
xSemaphoreTake(MutexSemaphore,portMAX_DELAY);
printf("low task Running!\r\n");
for(times=0;times<2000000;times++)
{
delay_us(2);
//taskYIELD();
}
xSemaphoreGive(MutexSemaphore);
vTaskDelay(1000); /* 延时1000ticks */
}
}
/**
* @brief task2
* @param pvParameters : 传入参数(未用到)
* @retval 无
*/
void Keyprocess_task(void *pvParameters)
{
while(1)
{
printf("middle task Running!\r\n");
vTaskDelay(1000);
}
}
void task3(void *pvParameters)
{
while(1)
{
printf("high task Pend Sem!\r\n");
xSemaphoreTake(MutexSemaphore,portMAX_DELAY);
printf("high task Running!\r\n");
xSemaphoreGive(MutexSemaphore);
vTaskDelay(1000);
}
}
/**
* @briefmain function.
* @paramnone
* @retval none
*/
int main(void)
{
system_clock_config();
delay_init();
/* init led2 and led3 */
at32_led_init(LED2);
at32_led_init(LED3);
at32_button_init();
/* init usart1 */
uart_print_init(115200);
MutexSemaphore=xSemaphoreCreateMutex();
if(MutexSemaphore==NULL)
{
printf("Sema Create Failed!\r\n");
}
/* create led2 task */
xTaskCreate(task1,
"vTask1",
128,
(void *)30,
2,
NULL);
xTaskCreate(Keyprocess_task,
"vTask2",
128,
NULL,
3,
NULL);
xTaskCreate(task3,
"vTask3",
128,
NULL,
4,
NULL);
/* start scheduler */
vTaskStartScheduler();
}
运行效果图：
这看不出来互斥啊，可以稍微讲解一下不。三个任务的执行过程 互斥信号量是为了解决优先级反转的问题，不是一两句话就能解释清楚的
页:
[1]