How to debug stm32F0 Can RX - raspberry-pi

Question

I have a custom stm32F0 board attached over can to a raspberry pi with a CAN shield, terminating resistors and everything. I can initiate a message on the STM32F0 and see it on the RPI side, but not vice-versa. Putting an oscilloscope on the can line, I see the message coming from the RPI. Similarly, I see the message between the can transceiver and the STM32F0, so I know the message is reaching the pin. The code for doing Rx seems straight-forward enough:
set up CAN
disable filters (by setting the filter to 0x0000)
set up can RX using HAL_CAN_ActivateNotification
set up the callback function for the can rx interrupt
Yet the interrupt never gets triggered. Is my CAN RX pin bad? How do I continue the debug process?
Here is the whole main.c:
/* USER CODE BEGIN Header */
/**
******************************************************************************
* #file : main.c
* #brief : Main program body
******************************************************************************
* #attention
*
* <h2><center>© Copyright (c) 2021 STMicroelectronics.
* All rights reserved.</center></h2>
*
* This software component is licensed by ST under BSD 3-Clause license,
* the "License"; You may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
* opensource.org/licenses/BSD-3-Clause
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
/* 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 ---------------------------------------------------------*/
CAN_HandleTypeDef hcan;
SPI_HandleTypeDef hspi1;
DMA_HandleTypeDef hdma_spi1_rx;
DMA_HandleTypeDef hdma_spi1_tx;
TIM_HandleTypeDef htim3;
TIM_HandleTypeDef htim14;
TIM_HandleTypeDef htim16;
TIM_HandleTypeDef htim17;
UART_HandleTypeDef huart1;
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_SPI1_Init(void);
static void MX_TIM16_Init(void);
static void MX_TIM14_Init(void);
static void MX_TIM17_Init(void);
static void MX_USART1_UART_Init(void);
static void MX_TIM3_Init(void);
static void MX_CAN_Init(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
CAN_TxHeaderTypeDef TxHeader;
CAN_RxHeaderTypeDef RxHeader;
uint32_t TxMailbox;
uint8_t TxData[8];
uint8_t RxData[8];
uint8_t count = 0;
uint8_t testData;
void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan){
count++;
HAL_CAN_GetRxMessage(hcan,CAN_RX_FIFO0,&RxHeader,RxData);
testData = RxData[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_DMA_Init();
MX_SPI1_Init();
MX_TIM16_Init();
MX_TIM14_Init();
MX_TIM17_Init();
MX_USART1_UART_Init();
MX_TIM3_Init();
MX_CAN_Init();
/* USER CODE BEGIN 2 */
HAL_CAN_Start(&hcan);
HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO0_MSG_PENDING);
TxHeader.DLC = 1;
TxHeader.ExtId = 0;
TxHeader.IDE = CAN_ID_STD;
TxHeader.RTR = CAN_RTR_DATA;
TxHeader.StdId = 0x103;
TxHeader.TransmitGlobalTime = DISABLE;
TxData[0] = 0xa7;
//HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
// HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox);
/* Start the Transmission process */
/* if (HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox) != HAL_OK)
{
Error_Handler();
}
*/ HAL_Delay(10);
/* 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};
RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI48;
RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
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_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI48;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
{
Error_Handler();
}
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART1;
PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK1;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
{
Error_Handler();
}
}
/**
* #brief CAN Initialization Function
* #param None
* #retval None
*/
static void MX_CAN_Init(void)
{
/* USER CODE BEGIN CAN_Init 0 */
/* USER CODE END CAN_Init 0 */
/* USER CODE BEGIN CAN_Init 1 */
/* USER CODE END CAN_Init 1 */
hcan.Instance = CAN;
hcan.Init.Prescaler = 6;
hcan.Init.Mode = CAN_MODE_NORMAL;
hcan.Init.SyncJumpWidth = CAN_SJW_1TQ;
hcan.Init.TimeSeg1 = CAN_BS1_13TQ;
hcan.Init.TimeSeg2 = CAN_BS2_2TQ;
hcan.Init.TimeTriggeredMode = DISABLE;
hcan.Init.AutoBusOff = DISABLE;
hcan.Init.AutoWakeUp = DISABLE;
hcan.Init.AutoRetransmission = DISABLE;
hcan.Init.ReceiveFifoLocked = DISABLE;
hcan.Init.TransmitFifoPriority = DISABLE;
if (HAL_CAN_Init(&hcan) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN CAN_Init 2 */
CAN_FilterTypeDef filterConfig;
filterConfig.FilterActivation = ENABLE;
filterConfig.FilterBank = 0;
filterConfig.FilterFIFOAssignment = CAN_RX_FIFO0;
filterConfig.FilterIdHigh = 0x0000;
filterConfig.FilterIdLow = 0x0000;
filterConfig.FilterMaskIdHigh = 0x0000;
filterConfig.FilterMaskIdLow = 0x0000;
filterConfig.FilterMode = CAN_FILTERMODE_IDMASK;
filterConfig.FilterScale = CAN_FILTERSCALE_32BIT;
filterConfig.SlaveStartFilterBank = 14;
/* USER CODE END CAN_Init 2 */
}
/**
* #brief SPI1 Initialization Function
* #param None
* #retval None
*/
static void MX_SPI1_Init(void)
{
/* USER CODE BEGIN SPI1_Init 0 */
/* USER CODE END SPI1_Init 0 */
/* USER CODE BEGIN SPI1_Init 1 */
/* USER CODE END SPI1_Init 1 */
/* SPI1 parameter configuration*/
hspi1.Instance = SPI1;
hspi1.Init.Mode = SPI_MODE_MASTER;
hspi1.Init.Direction = SPI_DIRECTION_2LINES;
hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi1.Init.NSS = SPI_NSS_SOFT;
hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_64;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 7;
hspi1.Init.CRCLength = SPI_CRC_LENGTH_DATASIZE;
hspi1.Init.NSSPMode = SPI_NSS_PULSE_ENABLE;
if (HAL_SPI_Init(&hspi1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN SPI1_Init 2 */
/* USER CODE END SPI1_Init 2 */
}
/**
* #brief TIM3 Initialization Function
* #param None
* #retval None
*/
static void MX_TIM3_Init(void)
{
/* USER CODE BEGIN TIM3_Init 0 */
/* USER CODE END TIM3_Init 0 */
TIM_ClockConfigTypeDef sClockSourceConfig = {0};
TIM_MasterConfigTypeDef sMasterConfig = {0};
/* USER CODE BEGIN TIM3_Init 1 */
/* USER CODE END TIM3_Init 1 */
htim3.Instance = TIM3;
htim3.Init.Prescaler = 480-1;
htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
htim3.Init.Period = 65535;
htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
{
Error_Handler();
}
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM3_Init 2 */
/* USER CODE END TIM3_Init 2 */
}
/**
* #brief TIM14 Initialization Function
* #param None
* #retval None
*/
static void MX_TIM14_Init(void)
{
/* USER CODE BEGIN TIM14_Init 0 */
/* USER CODE END TIM14_Init 0 */
/* USER CODE BEGIN TIM14_Init 1 */
/* USER CODE END TIM14_Init 1 */
htim14.Instance = TIM14;
htim14.Init.Prescaler = 48000 - 1;
htim14.Init.CounterMode = TIM_COUNTERMODE_UP;
htim14.Init.Period = 10- 1;
htim14.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim14.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim14) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM14_Init 2 */
/* USER CODE END TIM14_Init 2 */
}
/**
* #brief TIM16 Initialization Function
* #param None
* #retval None
*/
static void MX_TIM16_Init(void)
{
/* USER CODE BEGIN TIM16_Init 0 */
/* USER CODE END TIM16_Init 0 */
/* USER CODE BEGIN TIM16_Init 1 */
/* USER CODE END TIM16_Init 1 */
htim16.Instance = TIM16;
htim16.Init.Prescaler = 48000 - 1;
htim16.Init.CounterMode = TIM_COUNTERMODE_UP;
htim16.Init.Period = 10000 - 1;
htim16.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim16.Init.RepetitionCounter = 0;
htim16.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim16) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM16_Init 2 */
/* USER CODE END TIM16_Init 2 */
}
/**
* #brief TIM17 Initialization Function
* #param None
* #retval None
*/
static void MX_TIM17_Init(void)
{
/* USER CODE BEGIN TIM17_Init 0 */
/* USER CODE END TIM17_Init 0 */
/* USER CODE BEGIN TIM17_Init 1 */
/* USER CODE END TIM17_Init 1 */
htim17.Instance = TIM17;
htim17.Init.Prescaler = 48000 - 1;
htim17.Init.CounterMode = TIM_COUNTERMODE_UP;
htim17.Init.Period = 4 - 1;
htim17.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim17.Init.RepetitionCounter = 0;
htim17.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim17) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM17_Init 2 */
/* USER CODE END TIM17_Init 2 */
}
/**
* #brief USART1 Initialization Function
* #param None
* #retval None
*/
static void MX_USART1_UART_Init(void)
{
/* USER CODE BEGIN USART1_Init 0 */
/* USER CODE END USART1_Init 0 */
/* USER CODE BEGIN USART1_Init 1 */
/* USER CODE END USART1_Init 1 */
huart1.Instance = USART1;
huart1.Init.BaudRate = 9600;
huart1.Init.WordLength = UART_WORDLENGTH_8B;
huart1.Init.StopBits = UART_STOPBITS_1;
huart1.Init.Parity = UART_PARITY_NONE;
huart1.Init.Mode = UART_MODE_TX_RX;
huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart1.Init.OverSampling = UART_OVERSAMPLING_16;
huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&huart1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART1_Init 2 */
/* USER CODE END USART1_Init 2 */
}
/**
* Enable DMA controller clock
*/
static void MX_DMA_Init(void)
{
/* DMA controller clock enable */
__HAL_RCC_DMA1_CLK_ENABLE();
/* DMA interrupt init */
/* DMA1_Channel2_3_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA1_Channel2_3_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
}
/**
* #brief GPIO Initialization Function
* #param None
* #retval None
*/
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOF_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_15, GPIO_PIN_RESET);
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOB, cs1_gpio_Pin|cs2_gpio_Pin, GPIO_PIN_RESET);
/*Configure GPIO pin : VCP_TX_Pin */
GPIO_InitStruct.Pin = VCP_TX_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF1_USART2;
HAL_GPIO_Init(VCP_TX_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : PA15 */
GPIO_InitStruct.Pin = GPIO_PIN_15;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/*Configure GPIO pins : cs1_gpio_Pin cs2_gpio_Pin */
GPIO_InitStruct.Pin = cs1_gpio_Pin|cs2_gpio_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
}
/* USER CODE BEGIN 4 */
/* 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 */
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.
* #param file: pointer to the source file name
* #param 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,
tex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

Answer 1

Turned out the problem was actually the can transceiver. It has a stby pin which needs to be explicitly grounded, not left floating. This allows me to send messages from my stm32f0 over CAN. Unfortunately receiving messages has not been so easy. But that is a question for a different post.
One weird thing was that even though the transceiver was the one having the problem, the fact that it was on standby was affecting the outputs to the can tx from the stm32f0. Almost like it could cause problems "upstream". This made it more difficult to debug.