Question
Free RTOS queue mechanism does not work as expected.
Hi,
I have written below application. When manager task is scheduled for the 2nd time, the xStatus and xWorkTicketId get strange values as seen below.
When employee task is scheduled, xStatus gets "0" which indicates no variable in the queue waiting. This behaviour is strange, because there is variable in the queue.
Could you please help me sort out the issue ?
Thanks.
/* 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"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "FreeRTOS.h"
#include "task.h"
#include "semphr.h"
#include "queue.h"
#include <string.h>
#include <stdio.h>
#include "SEGGER_SYSVIEW.h"
#include <stdlib.h>
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define DWT_CTRL (*(volatile uint32_t*)0xE0001000)
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
UART_HandleTypeDef huart2;
/* USER CODE BEGIN PV */
TaskHandle_t xTaskHandleM = NULL;
TaskHandle_t xTaskHandleE =NULL;
char usr_msg[250] = {0};
xSemaphoreHandle xWork;
xQueueHandle xWorkQueue;
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
/* USER CODE BEGIN PFP */
static void vManagerTask(void *pvParameters);
static void vEmployeeTask(void *pvParameters);
void printmsg(char *msg);
/* USER CODE END PFP */
extern void SEGGER_UART_init(uint32_t baud);
/* 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 */
DWT->CTRL |=(1<<0);
/* 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 */
//SEGGER_UART_init(250000);
SEGGER_SYSVIEW_Conf();
//SEGGER_SYSVIEW_Start();
sprintf(usr_msg,"demo of binary semaphore usage between 2 tasks\r\n");
printmsg(usr_msg);
//create semaphore
vSemaphoreCreateBinary(xWork);
//crate queue to hold maximum of 1 element
xWorkQueue = xQueueCreate(1,sizeof(unsigned int));
//check semaphore and queue created successfully
if((xWork!=NULL)&&(xWorkQueue!=NULL))
{
/*create manager task. This task will be synchronized with the employee task. The manager task is created with a high priority*/
xTaskCreate(vManagerTask,"Manager",500, NULL,3, NULL);
/*Create employee task with less priority than manager*/
xTaskCreate(vEmployeeTask,"Employee",500,NULL,2,NULL);
/*Start the scheduler*/
vTaskStartScheduler();
}
else
{
sprintf(usr_msg,"Queue/sema crate failed..\r\n");
printmsg(usr_msg);
}
/* USER CODE END 2 */
/* 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 = 168;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
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_5) != 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)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOE_CLK_ENABLE();
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
__HAL_RCC_GPIOD_CLK_ENABLE();
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(CS_I2C_SPI_GPIO_Port, CS_I2C_SPI_Pin, GPIO_PIN_RESET);
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(OTG_FS_PowerSwitchOn_GPIO_Port, OTG_FS_PowerSwitchOn_Pin, GPIO_PIN_SET);
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOD, GreenLED_Pin|OrangeLED_Pin|RedLED_Pin|BlueLED_Pin
|Audio_RST_Pin, GPIO_PIN_RESET);
/*Configure GPIO pin : CS_I2C_SPI_Pin */
GPIO_InitStruct.Pin = CS_I2C_SPI_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(CS_I2C_SPI_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : OTG_FS_PowerSwitchOn_Pin */
GPIO_InitStruct.Pin = OTG_FS_PowerSwitchOn_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(OTG_FS_PowerSwitchOn_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : PDM_OUT_Pin */
GPIO_InitStruct.Pin = PDM_OUT_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF5_SPI2;
HAL_GPIO_Init(PDM_OUT_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : B1_Pin */
GPIO_InitStruct.Pin = B1_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(B1_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : I2S3_WS_Pin */
GPIO_InitStruct.Pin = I2S3_WS_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF6_SPI3;
HAL_GPIO_Init(I2S3_WS_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pins : SPI1_SCK_Pin SPI1_MISO_Pin SPI1_MOSI_Pin */
GPIO_InitStruct.Pin = SPI1_SCK_Pin|SPI1_MISO_Pin|SPI1_MOSI_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF5_SPI1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/*Configure GPIO pin : BOOT1_Pin */
GPIO_InitStruct.Pin = BOOT1_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(BOOT1_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : CLK_IN_Pin */
GPIO_InitStruct.Pin = CLK_IN_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF5_SPI2;
HAL_GPIO_Init(CLK_IN_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pins : GreenLED_Pin OrangeLED_Pin RedLED_Pin BlueLED_Pin
Audio_RST_Pin */
GPIO_InitStruct.Pin = GreenLED_Pin|OrangeLED_Pin|RedLED_Pin|BlueLED_Pin
|Audio_RST_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);
/*Configure GPIO pins : I2S3_MCK_Pin I2S3_SCK_Pin I2S3_SD_Pin */
GPIO_InitStruct.Pin = I2S3_MCK_Pin|I2S3_SCK_Pin|I2S3_SD_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF6_SPI3;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
/*Configure GPIO pin : VBUS_FS_Pin */
GPIO_InitStruct.Pin = VBUS_FS_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(VBUS_FS_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pins : OTG_FS_ID_Pin OTG_FS_DM_Pin OTG_FS_DP_Pin */
GPIO_InitStruct.Pin = OTG_FS_ID_Pin|OTG_FS_DM_Pin|OTG_FS_DP_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF10_OTG_FS;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/*Configure GPIO pin : OTG_FS_OverCurrent_Pin */
GPIO_InitStruct.Pin = OTG_FS_OverCurrent_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(OTG_FS_OverCurrent_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pins : Audio_SCL_Pin Audio_SDA_Pin */
GPIO_InitStruct.Pin = Audio_SCL_Pin|Audio_SDA_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF4_I2C1;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
/*Configure GPIO pin : MEMS_INT2_Pin */
GPIO_InitStruct.Pin = MEMS_INT2_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_EVT_RISING;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(MEMS_INT2_GPIO_Port, &GPIO_InitStruct);
/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}
/* USER CODE BEGIN 4 */
void EmployeeDoWork(unsigned char TicketId)
{
/*implement the work according to ticketID*/
sprintf(usr_msg,"Employee Task: working on Ticket id: %d\r\n",TicketId);
printmsg(usr_msg);
vTaskDelay(TicketId);
}
static void vManagerTask(void *pvParameters)
{
unsigned int xWorkTicketId;
portBASE_TYPE xStatus;
xSemaphoreGive(xWork);
/*the semaphore is created in the 'empty' state, meaning the semaphore must first be given using the xSemaphoreGive() API
function before it can be taken (obtained)*/
for(;;)
{
/*get a work ticket ID (some random number)*/
xSemaphoreTake(xWork,portMAX_DELAY);
char *msg1 = "manager tasks starts\n\r";
printmsg(msg1);
xWorkTicketId = (rand() & 0x1FF);
/*send the work ticket ID to the work queue*/
HAL_GPIO_TogglePin(GreenLED_GPIO_Port,GreenLED_Pin);
xStatus = xQueueSend(xWorkQueue,&xWorkTicketId,portMAX_DELAY); //post the item on back of the queue
xSemaphoreGive(xWork);
taskYIELD();
}
}
static void vEmployeeTask(void *pvParameters)
{
unsigned char xWorkTicketId;
portBASE_TYPE xStatus;
/*this task is also implemented in infinite loop*/
for(;;)
{
/*first employee tries to take semaphore, if thats available, then it means manager assigned a task*/
xSemaphoreGive(xWork);
char *msg1 = "employee tasks starts\n\r";
printmsg(msg1);
xSemaphoreTake(xWork,portMAX_DELAY);
/*get the ticket id from the work queue*/
xStatus = xQueueReceive(xWork, &xWorkTicketId, 0);
HAL_GPIO_TogglePin(OrangeLED_GPIO_Port,OrangeLED_Pin);
if(xStatus != pdPASS)
{
printmsg("empty queue nothing to do!\n\r");
/*employee will call a function to do the work*/
}
else
{
EmployeeDoWork(xWorkTicketId);
}
xSemaphoreGive(xWork);
taskYIELD();
}
}
void printmsg (char *msg)
{
HAL_UART_Transmit(&huart2, (uint8_t*)msg,strlen((char*)msg),HAL_MAX_DELAY);
}
/* USER CODE END 4 */
/**
* @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 */