实战：多任务传感器网关

项目目标与设计原则

整体架构

内核对象与任务规划

初始化：创建所有内核对象

#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "semphr.h"
#include "event_groups.h"
#include "timers.h"

/* 事件位定义 */
#define EV_WIFI  (1UL<<0)
#define EV_TIME  (1UL<<1)
#define EV_CFG   (1UL<<2)
#define EV_READY (EV_WIFI|EV_TIME|EV_CFG)
#define EV_BTN   (1UL<<8)
#define EV_ALARM (1UL<<9)

typedef struct { uint32_t ts; int16_t raw[4]; } SensorMsg;
typedef struct { uint32_t ts; float val[4]; }   Packet;

QueueHandle_t      g_rawQ, g_txQ;
SemaphoreHandle_t  g_i2cMutex, g_uartMutex;
EventGroupHandle_t g_sysEG;
TimerHandle_t      g_watchdog, g_health;
TaskHandle_t       g_sensorTask;

void app_init(void) {
  g_rawQ     = xQueueCreate(16, sizeof(SensorMsg));
  g_txQ      = xQueueCreate(8,  sizeof(Packet));
  g_i2cMutex = xSemaphoreCreateMutex();
  g_uartMutex= xSemaphoreCreateMutex();
  g_sysEG    = xEventGroupCreate();
  configASSERT(g_rawQ && g_txQ && g_i2cMutex && g_uartMutex && g_sysEG);

  g_watchdog = xTimerCreate("wd", pdMS_TO_TICKS(30000),
                            pdFALSE, NULL, LinkTimeoutCb);
  g_health   = xTimerCreate("hp", pdMS_TO_TICKS(60000),
                            pdTRUE,  NULL, HealthCb);

  xTaskCreate(MgrTask,    "MGR",  256, NULL, 5, NULL);
  xTaskCreate(SensorTask, "SEN",  384, NULL, 4, &g_sensorTask);
  xTaskCreate(ProcTask,   "PRC",  384, NULL, 3, NULL);
  xTaskCreate(CommTask,   "COM",  512, NULL, 2, NULL);

  xTimerStart(g_health, 0);
  vTaskStartScheduler();   /* 启动调度，不返回 */
}

采集任务：中断唤醒 + 互斥总线

/* DMA 完成中断：只清标志 + 唤醒采集任务 */
void DMA1_Stream0_IRQHandler(void) {
  BaseType_t woken = pdFALSE;
  __HAL_DMA_CLEAR_FLAG(&hdma_i2c, DMA_FLAG_TCIF0);
  vTaskNotifyGiveFromISR(g_sensorTask, &woken);
  portYIELD_FROM_ISR(woken);
}

void SensorTask(void *arg) {
  TickType_t last = xTaskGetTickCount();
  for (;;) {
    /* 严格 100ms 节拍触发一次采集 */
    vTaskDelayUntil(&last, pdMS_TO_TICKS(100));

    start_i2c_dma_read();                 /* 启动 DMA */
    ulTaskNotifyTake(pdTRUE,             /* 等 DMA 完成中断 */
                     pdMS_TO_TICKS(50));

    SensorMsg m; m.ts = xTaskGetTickCount();
    if (xSemaphoreTake(g_i2cMutex, pdMS_TO_TICKS(20))) {
      read_raw(m.raw);                    /* 临界区：独占 I2C */
      xSemaphoreGive(g_i2cMutex);
      /* 入队；满则丢最旧一帧策略视需求而定 */
      xQueueSend(g_rawQ, &m, 0);
    }
  }
}

处理任务与上报任务

void ProcTask(void *arg) {
  SensorMsg m; Packet p;
  for (;;) {
    /* 阻塞等原始数据；有数据才醒，利于低功耗 */
    if (xQueueReceive(g_rawQ, &m, portMAX_DELAY) == pdTRUE) {
      p.ts = m.ts;
      for (int i = 0; i < 4; i++)
        p.val[i] = filter_and_scale(m.raw[i]);
      xQueueSend(g_txQ, &p, pdMS_TO_TICKS(10));
    }
  }
}

void CommTask(void *arg) {
  Packet p;
  /* 等三大前置条件全就绪(AND)才开始上报 */
  xEventGroupWaitBits(g_sysEG, EV_READY,
                      pdFALSE, pdTRUE, portMAX_DELAY);
  xTimerStart(g_watchdog, 0);

  for (;;) {
    if (xQueueReceive(g_txQ, &p, portMAX_DELAY) == pdTRUE) {
      if (xSemaphoreTake(g_uartMutex, pdMS_TO_TICKS(100))) {
        bool ok = upload_with_retry(&p, 3);  /* 失败重试 3 次 */
        xSemaphoreGive(g_uartMutex);
        if (ok) xTimerReset(g_watchdog, 0);   /* 喂狗 */
      }
    }
  }
}

管理任务：OR 等待多路异步事件

/* 按键中断：给事件组置位 */
void EXTI0_IRQHandler(void) {
  BaseType_t woken = pdFALSE;
  __HAL_GPIO_EXTI_CLEAR_IT(GPIO_PIN_0);
  xEventGroupSetBitsFromISR(g_sysEG, EV_BTN, &woken);
  portYIELD_FROM_ISR(woken);
}

void MgrTask(void *arg) {
  for (;;) {
    EventBits_t b = xEventGroupWaitBits(
        g_sysEG, EV_BTN | EV_ALARM,
        pdTRUE,          /* 处理后清位 */
        pdFALSE,         /* OR：任一事件即处理 */
        portMAX_DELAY);
    if (b & EV_BTN)   handle_button();
    if (b & EV_ALARM) handle_alarm();
  }
}

/* 看门狗回调：长时间没成功上报→触发重连（简短，重活转任务） */
void LinkTimeoutCb(TimerHandle_t t) {
  (void) t;
  xEventGroupClearBits(g_sysEG, EV_WIFI);   /* 标记掉线 */
  request_reconnect();
}

/* 健康监控回调：定期打印统计与栈水位 */
void HealthCb(TimerHandle_t t) {
  (void) t;
  dump_cpu_usage();
  printf("heap free=%u\r\n",
         (unsigned)xPortGetFreeHeapSize());
}

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