First, the inter-task communication
1 event
Outline
The event provides a mechanism for inter-task synchronization and information transfer. In general, an event included a flag, the flag Each bit represents an "event."
A task can wait for the occurrence of one or more "events", and other tasks under certain conditions of business tasks can wait for this "event" by writing specific "event" wake-up, programming paradigms to achieve a similar signal.
API to explain
Programming Example
1, in tos_config.h, the event component configuration switch TOS_CFG_EVENT_EN:
#define TOS_CFG_EVENT_EN 1u
2, preparation of the sample code main.c:
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "usart.h"
#include "gpio.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "cmsis_os.h"
#include "stdio.h"
#include "tos_k.h"
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
#define STK_SIZE_TASK_LISTENER 512
#define STK_SIZE_TASK_TRIGGER 512
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
k_stack_t stack_task_listener1[STK_SIZE_TASK_LISTENER];
k_stack_t stack_task_listener2[STK_SIZE_TASK_LISTENER];
k_stack_t stack_task_trigger[STK_SIZE_TASK_TRIGGER];
k_task_t task_listener1;
k_task_t task_listener2;
k_task_t task_trigger;
extern void entry_task_listener1(void *arg);
extern void entry_task_listener2(void *arg);
extern void entry_task_trigger(void *arg);
const k_event_flag_t event_eeny = (k_event_flag_t)(1 << 0);
const k_event_flag_t event_meeny = (k_event_flag_t)(1 << 1);
const k_event_flag_t event_miny = (k_event_flag_t)(1 << 2);
const k_event_flag_t event_moe = (k_event_flag_t)(1 << 3);
k_event_t event;
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
void entry_task_listener1(void *arg)
{
k_event_flag_t flag_match;
k_err_t err;
while (K_TRUE) {
// 此任务监听四个事件，因为使用了TOS_OPT_EVENT_PEND_ALL选项，因此必须是四个事件同时到达此任务才会被唤醒
err = tos_event_pend(&event, event_eeny | event_meeny | event_miny | event_moe,
&flag_match, TOS_TIME_FOREVER, TOS_OPT_EVENT_PEND_ALL | TOS_OPT_EVENT_PEND_CLR);
if (err == K_ERR_NONE) {
printf("entry_task_listener1:\n");
printf("eeny, meeny, miny, moe, they all come\n");
}
}
}
void entry_task_listener2(void *arg)
{
k_event_flag_t flag_match;
k_err_t err;
while (K_TRUE) {
// 此任务监听四个事件，因为使用了TOS_OPT_EVENT_PEND_ANY选项，因此四个事件任意一个到达（包括四个事件同时到达）任务就会被唤醒
err = tos_event_pend(&event, event_eeny | event_meeny | event_miny | event_moe,
&flag_match, TOS_TIME_FOREVER, TOS_OPT_EVENT_PEND_ANY | TOS_OPT_EVENT_PEND_CLR);
if (err == K_ERR_NONE) {
printf("entry_task_listener2:\n");
// 有事件到达，判断具体是哪个事件
if (flag_match == event_eeny) {
printf("eeny comes\n");
}
if (flag_match == event_meeny) {
printf("meeny comes\n");
}
if (flag_match == event_miny) {
printf("miny comes\n");
}
if (flag_match == event_moe) {
printf("moe comes\n");
}
if (flag_match == (event_eeny | event_meeny | event_miny | event_moe)) {
printf("all come\n");
}
}
}
}
void entry_task_trigger(void *arg)
{
int i = 1;
while (K_TRUE) {
if (i == 2) {
printf("entry_task_trigger:\n");
printf("eeny will come\n");
// 发送eeny事件，task_listener2会被唤醒
tos_event_post(&event, event_eeny);
}
if (i == 3) {
printf("entry_task_trigger:\n");
printf("meeny will come\n");
// 发送eeny事件，task_listener2会被唤醒
tos_event_post(&event, event_meeny);
}
if (i == 4) {
printf("entry_task_trigger:\n");
printf("miny will come\n");
// 发送eeny事件，task_listener2会被唤醒
tos_event_post(&event, event_miny);
}
if (i == 5) {
printf("entry_task_trigger:\n");
printf("moe will come\n");
// 发送eeny事件，task_listener2会被唤醒
tos_event_post(&event, event_moe);
}
if (i == 6) {
printf("entry_task_trigger:\n");
printf("all will come\n");
// 同时发送四个事件，因为task_listener1的优先级高于task_listener2，因此这里task_listener1会被唤醒
tos_event_post(&event, event_eeny | event_meeny | event_miny | event_moe);
}
tos_task_delay(1000);
++i;
}
}
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
tos_knl_init();
tos_event_create(&event, (k_event_flag_t)0u);
// 这里task_listener1的优先级比task_listener2高，因此在task_trigger发送所有事件时，task_listener1会被唤醒
// 读者可以尝试将task_listener1优先级修改为5（比task_listener2低），此设置下，在task_trigger发送所有事件时，task_listener2将会被唤醒。
(void)tos_task_create(&task_listener1, "listener1", entry_task_listener1, NULL,
3, stack_task_listener1, STK_SIZE_TASK_LISTENER, 0);
(void)tos_task_create(&task_listener2, "listener2", entry_task_listener2, NULL,
4, stack_task_listener2, STK_SIZE_TASK_LISTENER, 0);
(void)tos_task_create(&task_trigger, "trigger", entry_task_trigger, NULL,
4, stack_task_trigger, STK_SIZE_TASK_TRIGGER, 0);
tos_knl_start();
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
3, operating results
