关于freertos介绍
http://blog.csdn.net/qq_38288618/article/details/76448806
资源下载
https://github.com/feilipu/Arduino_FreeRTOS_Library
测试源码
#include <Arduino_FreeRTOS.h>
#include <semphr.h> // add the FreeRTOS functions for Semaphores (or Flags).
// Declare a mutex Semaphore Handle which we will use to manage the Serial Port.
//声明信互斥号量用它来管理串口
// It will be used to ensure only only one Task is accessing this resource at any time.
//某时刻只有一个任务能获取到串口通讯这个资源
SemaphoreHandle_t xSerialSemaphore;
// define two Tasks for DigitalRead & AnalogRead
//定义两个任务DigitalRead 和 AnalogRead
void TaskDigitalRead( void *pvParameters );
void TaskAnalogRead( void *pvParameters );
void TaskInerrupt0Effect( void *pvParameters );
volatile int state = LOW;
void blink()
{
state = !state;
}
//设置中断
void setupInerrupt0()
{
attachInterrupt(0, blink, CHANGE);
//attachInterrupt(pin, ISR, mode)
//mode:定义中断触发类型，有四种形式：
//LOW：低电平触发；
//CHANGE：电平变化触发；
//RISING ：上升沿触发（由LOW变为HIGH）；
//FALLING：下降沿触发（由HIGH变为LOW）；
//Due板子还支持高电平触发。
}
// the setup function runs once when you press reset or power the board
// 当上电或reset时setup函数只运行一次
void setup() {
setupInerrupt0();
// initialize serial communication at 9600 bits per second:
//初始化串口连接波特率
Serial.begin(115200);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB, on LEONARDO, MICRO, YUN, and other 32u4 based boards.
//等待串口连接。需要LEONARDO, MICRO, YUN, 或其他 32u4板子上的usb接口
}
// Semaphores are useful to stop a Task proceeding, where it should be paused to wait,
//信号量在需要让一个任务进程停一会儿时很有用，它让任务处于暂停等待的状态，
// because it is sharing a resource, such as the Serial port.
//就像串口这样的共享资源
// Semaphores should only be used whilst the scheduler is running, but we can set it up here.
//信号量应该只在调度运行的时候使用，在这里我们可以对它进行设置。
if ( xSerialSemaphore == NULL ) // Check to confirm that the Serial Semaphore has not already been created.//检查确认串口信号没被创建。
{
xSerialSemaphore = xSemaphoreCreateMutex(); // Create a mutex semaphore we will use to manage the Serial Port//创建信号来管理串口
if ( ( xSerialSemaphore ) != NULL )
xSemaphoreGive( ( xSerialSemaphore ) ); // Make the Serial Port available for use, by "Giving" the Semaphore.//调用xSemaphoreGive （“给”信号）使串口处于有效状态（没被占用）
}
// Now set up two Tasks to run independently.
//现在设置两个任务互不影响的运行。
xTaskCreate(
TaskDigitalRead
, (const portCHAR *)"DigitalRead" // A name just for humans//只是人可识别的名称
, 128 // This stack size can be checked & adjusted by reading the Stack Highwater堆栈大小可以被检查调整，通过读。。。
, NULL
, 2 // Priority, with 3 (configMAX_PRIORITIES - 1) being the highest, and 0 being the lowest.优先级3(configMAX_PRIORITIES - 1)最大0最小
, NULL );
xTaskCreate(
TaskAnalogRead
, (const portCHAR *) "AnalogRead"
, 128 // Stack size
, NULL
, 1 // Priority
, NULL );
xTaskCreate(
vLEDFlashTask
, (const portCHAR *) "LEDFlash"
, 128 // Stack size
, NULL
, 1 // Priority
, NULL );
xTaskCreate(
TaskInerrupt0Effect
, (const portCHAR *) "Inerrupt0Effect"
, 128 // Stack size
, NULL
, 3 // Priority
, NULL );
// Now the Task scheduler, which takes over control of scheduling individual Tasks, is automatically started.
//现在，任务调度程序开始自动控制调度单个任务，它将自动启动。
}
void loop()
{
// Empty. Things are done in Tasks.
//所有事情都在每个任务里做，这里留空。
}
/*--------------------------------------------------*/
/*---------------------- Tasks ---------------------*/
/*--------------------------------------------------*/
// high priority for blinking LED
//闪灯任务高优先级
const uint8_t LED_PIN = 3;
static void vLEDFlashTask(void *pvParameters)
{
pinMode(LED_PIN, OUTPUT);
// Flash led every 200 ms.
//led每200ms闪烁一次
for (;;)
{
digitalWrite(LED_PIN, HIGH); // Turn LED on.点亮led
vTaskDelay((50L * configTICK_RATE_HZ) / 1000L);// Sleep for 50 milliseconds.//延时50ms
pinMode(LED_PIN, INPUT);//设置针脚为input
if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )
{
Serial.println(digitalRead(LED_PIN));
xSemaphoreGive( xSerialSemaphore ); // Now free or "Give" the Serial Port for others.//释放串口给其他任务使用
}
pinMode(LED_PIN, OUTPUT);
digitalWrite(LED_PIN, LOW); // Turn LED off.关闭led
vTaskDelay((150L * configTICK_RATE_HZ) / 1000L); // Sleep for 150 milliseconds.延时150ms
pinMode(LED_PIN, INPUT);
if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )
{
Serial.println(digitalRead(LED_PIN));
xSemaphoreGive( xSerialSemaphore ); // Now free or "Give" the Serial Port for others.
}
pinMode(LED_PIN, OUTPUT);
vTaskDelay(100);//1500ms
}
}
void TaskDigitalRead( void *pvParameters __attribute__((unused)) ) // This is a Task.
{
/*
DigitalReadSerial
Reads a digital input on pin 2, prints the result to the serial monitor
This example code is in the public domain.
读取pin2的数字输入，然后用串口打印出来
*/
// digital pin 2 has a pushbutton attached to it. Give it a name:
uint8_t pushButton = 2;
// make the pushbutton's pin an input:
pinMode(pushButton, INPUT);
for (;;) // A Task shall never return or exit.
{
// read the input pin:
int buttonState = digitalRead(pushButton);
if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )
{
Serial.print("B:");
Serial.println(buttonState);
xSemaphoreGive( xSerialSemaphore );
}
vTaskDelay(5);
}
}
void TaskAnalogRead( void *pvParameters __attribute__((unused)) ) // This is a Task.
{
for (;;)
{
// read the input on analog pin 012:
int x,y,z,sw;
x=analogRead(A0);
y=analogRead(A1);
sw= analogRead(A2);
z= (sw<50) ?0:1;
// See if we can obtain or "Take" the Serial Semaphore.
//看是否能拿到使用串口的信号
// If the semaphore is not available, wait 5 ticks of the Scheduler to see if it becomes free.
//如果信号无效，调度程序等5个tick再看信号是否被释放
if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )
{
// We were able to obtain or "Take" the semaphore and can now access the shared resource.
// We want to have the Serial Port for us alone, as it takes some time to print,
// so we don't want it getting stolen during the middle of a conversion.
// print out the value you read:
//我们能获取到了信号量，就可以访问共享资源。
//因为需要一些时间来输出信息，所以我们此时想单独占有串口资源，
//所以我们不希望串口资源在这个交互过程中被别的任务抢走。
//打印出所读的值：
//Serial.println(sensorValue);
Serial.print("X:");
Serial.print(x);
Serial.print(":Y:");
Serial.print(y);
Serial.print(":sw:");
Serial.print(sw);
Serial.print(":z:");
Serial.println(z);
xSemaphoreGive( xSerialSemaphore ); // Now free or "Give" the Serial Port for others.//释放使用完的串口资源
}
vTaskDelay(10); // one tick delay (15ms) in between reads for stability//为了稳定读取延时100tick ，1个tick 15ms
}
}
void TaskInerrupt0Effect( void *pvParameters __attribute__((unused)) ) // This is a Task.
{
int pin = 13;
pinMode(pin, OUTPUT);
for (;;)
{
digitalWrite(pin, state);
vTaskDelay(10);
}
}