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Free RTOS queue mechanism does not work as expected.

demir
Senior II

Hi,

I have created two tasks. Task A and Task B. Task A has higher priority. Task receives data through UART and enques this data into queue. Then, Task A is blocked for 1 second. Task B comes into picture and dequeues the data from queue. I send 8 bytes of data, I can see that Task A writes to buff array when I send message through via serial terminal on UART.

demir_0-1710088589010.png

I send buff array to the queue, then I enqueue the data from queue and write it into buff2 array. When I read the buff2 array I only see the first byte of buff array.

 

demir_1-1710088719866.png

Please see below serial terminal output.

 

demir_0-1710089346378.png

 

 

 

/* USER CODE BEGIN Header */ /** ****************************************************************************** * @file : main.c * @brief : Main program body ****************************************************************************** * @attention * * Copyright (c) 2024 STMicroelectronics. * All rights reserved. * * This software is licensed under terms that can be found in the LICENSE file * in the root directory of this software component. * If no LICENSE file comes with this software, it is provided AS-IS. * ****************************************************************************** */ /* USER CODE END Header */ /* Includes ------------------------------------------------------------------*/ #include "main.h" #include "cmsis_os.h" /* Private includes ----------------------------------------------------------*/ /* USER CODE BEGIN Includes */ #include <string.h> /* USER CODE END Includes */ /* Private typedef -----------------------------------------------------------*/ /* USER CODE BEGIN PTD */ /* USER CODE END PTD */ /* Private define ------------------------------------------------------------*/ /* USER CODE BEGIN PD */ /* USER CODE END PD */ /* Private macro -------------------------------------------------------------*/ /* USER CODE BEGIN PM */ /* USER CODE END PM */ /* Private variables ---------------------------------------------------------*/ UART_HandleTypeDef huart2; osThreadId TaskBHandle; osThreadId TaskAHandle; osMessageQId msgQueueHandle; /* USER CODE BEGIN PV */ uint8_t buff[50]; uint8_t buff2[50]; /* USER CODE END PV */ /* Private function prototypes -----------------------------------------------*/ void SystemClock_Config(void); static void MX_GPIO_Init(void); static void MX_USART2_UART_Init(void); void StartTaskB(void const * argument); void StartTaskA(void const * argument); /* 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_USART2_UART_Init(); /* USER CODE BEGIN 2 */ /* USER CODE END 2 */ /* USER CODE BEGIN RTOS_MUTEX */ /* add mutexes, ... */ /* USER CODE END RTOS_MUTEX */ /* USER CODE BEGIN RTOS_SEMAPHORES */ /* add semaphores, ... */ /* USER CODE END RTOS_SEMAPHORES */ /* USER CODE BEGIN RTOS_TIMERS */ /* start timers, add new ones, ... */ /* USER CODE END RTOS_TIMERS */ /* Create the queue(s) */ /* definition and creation of msgQueue */ osMessageQDef(msgQueue, 50, uint8_t); msgQueueHandle = osMessageCreate(osMessageQ(msgQueue), NULL); /* USER CODE BEGIN RTOS_QUEUES */ /* add queues, ... */ /* USER CODE END RTOS_QUEUES */ /* Create the thread(s) */ /* definition and creation of TaskB */ osThreadDef(TaskB, StartTaskB, osPriorityNormal, 0, 128); TaskBHandle = osThreadCreate(osThread(TaskB), NULL); /* definition and creation of TaskA */ osThreadDef(TaskA, StartTaskA, osPriorityAboveNormal, 0, 128); TaskAHandle = osThreadCreate(osThread(TaskA), NULL); /* USER CODE BEGIN RTOS_THREADS */ /* add threads, ... */ /* USER CODE END RTOS_THREADS */ /* Start scheduler */ osKernelStart(); /* We should never get here as control is now taken by the scheduler */ /* Infinite loop */ /* USER CODE BEGIN WHILE */ while (1) { /* USER CODE END WHILE */ /* USER CODE BEGIN 3 */ } /* USER CODE END 3 */ } /** * @brief System Clock Configuration * @retval None */ void SystemClock_Config(void) { RCC_OscInitTypeDef RCC_OscInitStruct = {0}; RCC_ClkInitTypeDef RCC_ClkInitStruct = {0}; /** Configure the main internal regulator output voltage */ __HAL_RCC_PWR_CLK_ENABLE(); __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1); /** Initializes the RCC Oscillators according to the specified parameters * in the RCC_OscInitTypeDef structure. */ RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI; RCC_OscInitStruct.HSIState = RCC_HSI_ON; RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT; RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON; RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI; RCC_OscInitStruct.PLL.PLLM = 8; RCC_OscInitStruct.PLL.PLLN = 50; RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4; RCC_OscInitStruct.PLL.PLLQ = 7; if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) { Error_Handler(); } /** Initializes the CPU, AHB and APB buses clocks */ RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2; RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK; RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1; RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4; RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2; if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK) { Error_Handler(); } } /** * @brief USART2 Initialization Function * None * @retval None */ static void MX_USART2_UART_Init(void) { /* USER CODE BEGIN USART2_Init 0 */ /* USER CODE END USART2_Init 0 */ /* USER CODE BEGIN USART2_Init 1 */ /* USER CODE END USART2_Init 1 */ huart2.Instance = USART2; huart2.Init.BaudRate = 115200; huart2.Init.WordLength = UART_WORDLENGTH_8B; huart2.Init.StopBits = UART_STOPBITS_1; huart2.Init.Parity = UART_PARITY_NONE; huart2.Init.Mode = UART_MODE_TX_RX; huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE; huart2.Init.OverSampling = UART_OVERSAMPLING_16; if (HAL_UART_Init(&huart2) != HAL_OK) { Error_Handler(); } /* USER CODE BEGIN USART2_Init 2 */ /* USER CODE END USART2_Init 2 */ } /** * @brief GPIO Initialization Function * None * @retval None */ static void MX_GPIO_Init(void) { /* USER CODE BEGIN MX_GPIO_Init_1 */ /* USER CODE END MX_GPIO_Init_1 */ /* GPIO Ports Clock Enable */ __HAL_RCC_GPIOA_CLK_ENABLE(); /* USER CODE BEGIN MX_GPIO_Init_2 */ /* USER CODE END MX_GPIO_Init_2 */ } /* USER CODE BEGIN 4 */ void printmsg (void * msg) { HAL_UART_Transmit(&huart2, (uint8_t*)msg,strlen(msg),100); } /* USER CODE END 4 */ /* USER CODE BEGIN Header_StartTaskB */ /** * @brief Function implementing the TaskB thread. * argument: Not used * @retval None */ /* USER CODE END Header_StartTaskB */ void StartTaskB(void const * argument) { /* USER CODE BEGIN 5 */ /* Infinite loop */ for(;;) { xQueueReceive(msgQueueHandle, (void*)&buff2,pdMS_TO_TICKS(100)); HAL_UART_Transmit(&huart2, buff2, sizeof(buff2),1000); osDelay(1000); } /* USER CODE END 5 */ } /* USER CODE BEGIN Header_StartTaskA */ /** * @brief Function implementing the TaskA thread. * argument: Not used * @retval None */ /* USER CODE END Header_StartTaskA */ void StartTaskA(void const * argument) { /* USER CODE BEGIN StartTaskA */ /* Infinite loop */ for(;;) { HAL_UART_Receive(&huart2, &buff, sizeof(buff),2000); xQueueSend(msgQueueHandle,(void*)&buff ,pdMS_TO_TICKS(100)); osDelay(1000); } /* USER CODE END StartTaskA */ } /** * @brief Period elapsed callback in non blocking mode * @note This function is called when TIM6 interrupt took place, inside * HAL_TIM_IRQHandler(). It makes a direct call to HAL_IncTick() to increment * a global variable "uwTick" used as application time base. * htim : TIM handle * @retval None */ void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim) { /* USER CODE BEGIN Callback 0 */ /* USER CODE END Callback 0 */ if (htim->Instance == TIM6) { HAL_IncTick(); } /* USER CODE BEGIN Callback 1 */ /* USER CODE END Callback 1 */ } /** * @brief This function is executed in case of error occurrence. * @retval None */ void Error_Handler(void) { /* USER CODE BEGIN Error_Handler_Debug */ /* User can add his own implementation to report the HAL error return state */ __disable_irq(); while (1) { } /* USER CODE END Error_Handler_Debug */ } #ifdef USE_FULL_ASSERT /** * @brief Reports the name of the source file and the source line number * where the assert_param error has occurred. * file: pointer to the source file name * line: assert_param error line source number * @retval None */ void assert_failed(uint8_t *file, uint32_t line) { /* USER CODE BEGIN 6 */ /* User can add his own implementation to report the file name and line number, ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */ /* USER CODE END 6 */ } #endif /* USE_FULL_ASSERT */
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Can anyone please help me sort this issue ?

Thank you.

1 ACCEPTED SOLUTION

Accepted Solutions
Pavel A.
Super User

> osMessageQDef(msgQueue, 50, uint8_t);

This means: queue of 50 elements, size (uint8_t) each. So task A stores one queue element (one char) and task B reads this element, one char. To send N chars, call xQueueSend N times. You may want to use the native FreeRTOS API instead of CMSIS-RTOS for clarity. 

 

 

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1 REPLY 1
Pavel A.
Super User

> osMessageQDef(msgQueue, 50, uint8_t);

This means: queue of 50 elements, size (uint8_t) each. So task A stores one queue element (one char) and task B reads this element, one char. To send N chars, call xQueueSend N times. You may want to use the native FreeRTOS API instead of CMSIS-RTOS for clarity.