Solved
FDCAN Tx callback not triggered on STM32U5
I’ve written code that performs a CAN Tx transmission when an interrupt occurs while in STOP2 mode.
The transmission request via HAL_FDCAN_AddMessageToTxFifoQ() succeeds,
but the HAL_FDCAN_TxEventFifoCallback(FDCAN_HandleTypeDef *hfdcan, uint32_t TxEventFifoITs) callback is never triggered.
The GPIO interrupt callback (HAL_GPIO_EXTI_Rising_Callback) works as expected,
and I can see "HAL_CAN_AddTxMessage start" being printed, which means the transmission request was made.
However, it seems like the transmission is not actually completed.
Why is the Tx event not being triggered?
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* Copyright (c) 2025 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 "fdcan.h"
#include "icache.h"
#include "memorymap.h"
#include "usart.h"
#include "gpio.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <stdio.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 ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
__IO uint32_t PushButtonState = PB_NOT_PRESSED;
FDCAN_RxHeaderTypeDef RxHeader;
uint8_t RxData[8]={0,1,0,0,0,0,0,0};
FDCAN_TxHeaderTypeDef TxHeader;
uint8_t TxData[8]={0,0,0,0,0,0,0,0};
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void SystemPower_Config(void);
/* USER CODE BEGIN PFP */
void FDCAN_Config(void);
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
int _write(int fd, char *ptr, int len)
{
HAL_UART_Transmit(&huart1, (unsigned char*)ptr, len, HAL_MAX_DELAY);
return len;
}
/* 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 Power */
SystemPower_Config();
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_ICACHE_Init();
MX_FDCAN1_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
FDCAN_Config();
uint8_t buffer[256];
sprintf((char *)buffer, "START!\r\n");
HAL_UART_Transmit(&huart1, buffer, strlen((char *)buffer), 100);
HAL_FDCAN_ActivateNotification(&hfdcan1, FDCAN_IT_TX_EVT_FIFO_NEW_DATA, 0);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{ __HAL_PWR_CLEAR_FLAG(PWR_FLAG_SBF);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, 1);
HAL_Delay(5000);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, 0);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_6, 0);
PushButtonState = PB_NOT_PRESSED;
uint8_t buffer[256];
sprintf((char *)buffer, "Enter STOP2 MODE\r\n");
HAL_UART_Transmit(&huart1, buffer, strlen((char *)buffer), 100);
__HAL_RCC_PWR_CLK_ENABLE ();
HAL_PWREx_EnterSTOP2Mode(PWR_SLEEPENTRY_WFI);
SystemClock_Config();
MX_FDCAN1_Init();
FDCAN_Config();
HAL_NVIC_ClearPendingIRQ(EXTI13_IRQn);
HAL_NVIC_EnableIRQ(EXTI13_IRQn);
while (PushButtonState == PB_NOT_PRESSED);
/* 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
*/
if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE3) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
RCC_OscInitStruct.MSIState = RCC_MSI_ON;
RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;
RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_4;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_MSI;
RCC_OscInitStruct.PLL.PLLMBOOST = RCC_PLLMBOOST_DIV1;
RCC_OscInitStruct.PLL.PLLM = 1;
RCC_OscInitStruct.PLL.PLLN = 32;
RCC_OscInitStruct.PLL.PLLP = 2;
RCC_OscInitStruct.PLL.PLLQ = 32;
RCC_OscInitStruct.PLL.PLLR = 2;
RCC_OscInitStruct.PLL.PLLRGE = RCC_PLLVCIRANGE_0;
RCC_OscInitStruct.PLL.PLLFRACN = 0;
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_CLOCKTYPE_PCLK3;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB3CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief Power Configuration
* @retval None
*/
static void SystemPower_Config(void)
{
/*
* Switch to SMPS regulator instead of LDO
*/
if (HAL_PWREx_ConfigSupply(PWR_SMPS_SUPPLY) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN PWR */
/* USER CODE END PWR */
}
/* USER CODE BEGIN 4 */
void HAL_GPIO_EXTI_Rising_Callback(uint16_t GPIO_Pin)
{ //SystemClock_Config();
/* Prevent unused argument(s) compilation warning */
if(GPIO_Pin == BTN_Pin)
{
PushButtonState = PB_PRESSED;
printf("▶▶\r\n");
if (HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan1, &TxHeader, TxData) != HAL_OK)
{
printf("HAL_CAN_AddTxMessage error\r\n");
HAL_Delay(100);
}
else
{
printf("HAL_CAN_AddTxMessage start\r\n");
HAL_Delay(100);
}
}
}
void HAL_FDCAN_TxEventFifoCallback(FDCAN_HandleTypeDef *hfdcan, uint32_t TxEventFifoITs)
{
printf("HAL_FDCAN_TxEventFifoCallback\r\n");
if (TxEventFifoITs & FDCAN_IT_TX_EVT_FIFO_NEW_DATA)
{
printf("HAL_CAN_AddTxMessage completed\r\n");
}
}
void HAL_FDCAN_RxFifo0Callback(FDCAN_HandleTypeDef *hfdcan, uint32_t RxFifo0ITs)
{
if((RxFifo0ITs & FDCAN_IT_RX_FIFO0_NEW_MESSAGE) != RESET)
{
/* Retrieve Rx messages from RX FIFO0 */
if (HAL_FDCAN_GetRxMessage(hfdcan, FDCAN_RX_FIFO0, &RxHeader, RxData) != HAL_OK)
{
Error_Handler();
}
for(int i=0; i<TxHeader.DataLength; i++)
{
printf("RxData[%d] = %d\r\n", i, RxData[i]);
HAL_Delay(100);
}
}
}
void FDCAN_Config(void)
{
FDCAN_FilterTypeDef sFilterConfig;
hfdcan1.Init.AutoRetransmission = ENABLE;
HAL_FDCAN_ConfigInterruptLines(&hfdcan1, FDCAN_IT_TX_EVT_FIFO_NEW_DATA, FDCAN_INTERRUPT_LINE0);
HAL_FDCAN_ActivateNotification(&hfdcan1, FDCAN_IT_TX_EVT_FIFO_NEW_DATA, 0);
/* Configure Rx filter */
sFilterConfig.IdType = FDCAN_STANDARD_ID;
sFilterConfig.FilterIndex = 0;
sFilterConfig.FilterType = FDCAN_FILTER_RANGE;
sFilterConfig.FilterConfig = FDCAN_FILTER_TO_RXFIFO0;
sFilterConfig.FilterID1 = 0x321;
sFilterConfig.FilterID2 = 0x7FF;
if (HAL_FDCAN_ConfigFilter(&hfdcan1, &sFilterConfig) != HAL_OK)
{
Error_Handler();
}
/* Start the FDCAN module */
if (HAL_FDCAN_Start(&hfdcan1) != HAL_OK)
{
Error_Handler();
}
if (HAL_FDCAN_ActivateNotification(&hfdcan1, FDCAN_IT_RX_FIFO0_NEW_MESSAGE, 0) != HAL_OK)
{
Error_Handler();
}
/* Prepare Tx Header */
TxHeader.Identifier = 0x321;
TxHeader.IdType = FDCAN_STANDARD_ID;
TxHeader.TxFrameType = FDCAN_DATA_FRAME;
TxHeader.DataLength = FDCAN_DLC_BYTES_2; //보낼 바이트 값 설정
TxHeader.ErrorStateIndicator = FDCAN_ESI_PASSIVE;
TxHeader.BitRateSwitch = FDCAN_BRS_OFF;
TxHeader.FDFormat = FDCAN_CLASSIC_CAN;
TxHeader.TxEventFifoControl = FDCAN_STORE_TX_EVENTS;
TxHeader.MessageMarker = 0;
HAL_FDCAN_Start(&hfdcan1);
}
/* USER CODE END 4 */
/**
* @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 */