1. 代码

//sem.c

#include <rtthread.h>
#include <rtdevice.h>
#include "drv_gpio.h"#define THREAD_PRIORITY 25
#define THREAD_TIMESLICE 5#define LED3_PIN GET_PIN(B, 3)
ALIGN(RT_ALIGN_SIZE)
static char thread3_stack[1024];
static struct rt_thread thread3;
static struct rt_semaphore keyPress1_sem;
void KeyScanCallBack(void)
{rt_sem_release(&keyPress1_sem); 
}
static void rt_thread3_entry(void *parameter)
{static rt_err_t result;
//  static int cnt = 0;while(1){/* 永 久 方 式 等 待 信 号 量， 获 取 到 信 号 量， 则 执 行 number 自 加 的 操 作 */result = rt_sem_take(&keyPress1_sem, RT_WAITING_FOREVER);if (result != RT_EOK){rt_kprintf("t3 take a static semaphore, failed.\n");return;}else{rt_kprintf("t3 take a static semaphore");rt_pin_write(LED3_PIN, PIN_HIGH);rt_thread_mdelay(1000);rt_pin_write(LED3_PIN, PIN_LOW);
//      if(++cnt >= 5)
//      {
//        rt_sem_detach(&keyPress1_sem);
//        return;
//      }}}
}void Key1PressTaskInit(void)
{/* 初 始 化 3 个 信 号 量 */rt_sem_init(&keyPress1_sem, "keyPress1_sem", 0, RT_IPC_FLAG_FIFO);rt_pin_mode(LED3_PIN, PIN_MODE_OUTPUT);rt_thread_init(&thread3,"thread3",rt_thread3_entry,RT_NULL,&thread3_stack[0],sizeof(thread3_stack),THREAD_PRIORITY-1, THREAD_TIMESLICE);  rt_thread_startup(&thread3);  
}

//usrtimer.c

#include <rtthread.h>
#include <rtdevice.h>
#include "drv_gpio.h"/* 定时器的控制块 */
static struct rt_timer timer3;
static int cnt = 0;#define KEY1_PIN GET_PIN(C, 5)static uint8_t keyVal = 0;void KeyScanCallBack(void);
static void keyscan(void* parameter)
{static uint8_t i = 0;uint8_t val;val = rt_pin_read(KEY1_PIN);if(val == 0){if(i < 200){i ++;}}else{if(i >= 2){keyVal = 1;rt_kprintf("key press val is %d\n",keyVal);KeyScanCallBack();keyVal = 0;}i = 0;}
}void keyscan_init(void)
{rt_pin_mode(KEY1_PIN, PIN_MODE_INPUT);rt_timer_init(&timer3, "timerKeyscan",   /* 定时器名字是 timer2 */keyscan, /* 超时时回调的处理函数 */RT_NULL, /* 超时函数的入口参数 */5, /* 定时长度为 5 个 OS Tick */RT_TIMER_FLAG_PERIODIC); /* 单次定时器 */  rt_timer_start(&timer3);
}

//main.c

#include <rthw.h>
#include <stdio.h>
#include <rtthread.h>
#include <rtdevice.h>
#include "drv_gpio.h"
#include "gd32f3x0.h"/* defined the LED2 pin: PC6 */
#define LED1_PIN GET_PIN(B, 1)
#define LED2_PIN GET_PIN(B, 2)#define delay_ms(x)   rt_thread_mdelay(x)#define RT_USR1_THREAD_PRIO        6
#define USR1_THREAD_NAME          "usr1"
static struct rt_thread usr1_thread;
static rt_uint8_t usr1_thread_stack[500];void rt_thread_usr1_entry(void *parameter)
{/* set LED2 pin mode to output */rt_pin_mode(LED2_PIN, PIN_MODE_OUTPUT);while (1){rt_pin_write(LED2_PIN, PIN_HIGH);rt_thread_mdelay(2000);rt_pin_write(LED2_PIN, PIN_LOW);rt_thread_mdelay(3000);} 
}void keyscan_init(void);
void Key1PressTaskInit(void);int main(void)
{keyscan_init();Key1PressTaskInit();rt_thread_init(&usr1_thread,USR1_THREAD_NAME,rt_thread_usr1_entry,RT_NULL,&usr1_thread_stack[0],sizeof(usr1_thread_stack),RT_USR1_THREAD_PRIO,20);rt_thread_startup(&usr1_thread);/* set LED1 pin mode to output */rt_pin_mode(LED1_PIN, PIN_MODE_OUTPUT);while (1){rt_pin_write(LED1_PIN, PIN_HIGH);rt_thread_mdelay(500);rt_pin_write(LED1_PIN, PIN_LOW);rt_thread_mdelay(600);}
}

2.测试

按键一次，rt_sem_release(&keyPress1_sem);执行一次信号量值value加1。按键可以很快，但rt_thread3_entry()执行以下需要1s多。

rt_kprintf("t3 take a static semaphore");
rt_pin_write(LED3_PIN, PIN_HIGH);
rt_thread_mdelay(1000);
rt_pin_write(LED3_PIN, PIN_LOW);

即生产过快，消耗过慢。