Receiving random data bytes during STM32 CAN communication Rx - c

Question

I'm using STM32F103RBT6 Nucleo board with CAN communication for my project. I use Microchip CAN Bus Analyzer(acts as a node) to transmit CAN data.
Project Setup:
CAN message flow from: CAN Bus Analyzer --> CAN Transceiver --> STM board.
I need to receive messages only from 0x581, 0x582, 0x583, 0x584, 0x4A1, 0x4A2, 0X4A3, 0X4A4 IDs. In order to achieve this I have applied filters for the same.
Problem:
In Keil's debugger mode, I'm able to see the CAN messages which are transmitted, getting received in 'RxData' properly. However when I try to send data of 4 bytes length, RxData data bytes from 1 to 4 gets filled with the exact same message that I transmit, but data bytes 5 to 8 also gets filled randomly (In ideal case, bytes 5 to 8 should all be zero). This problem happens only when I send data of byte length 4. I tried sending data bytes of varying length (other than 4), it worked just fine. The problem lies only whenever I try to send data byte of length 4.
I have attached my entire program code below. And attached screenshots of the issue. Please find below.
#include "main.h"
CAN_HandleTypeDef hcan;
CAN_TxHeaderTypeDef TxHeader;
CAN_RxHeaderTypeDef RxHeader;
CAN_FilterTypeDef sFilterConfig;
uint8_t RxData[8];
uint8_t TxData[8];
uint32_t TxMailbox;
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_CAN_Init(void);
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_CAN_Init();
while (1)
{
// Empty while.
}
}
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
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_DIV2;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL12;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
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_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
{
Error_Handler();
}
}
static void MX_CAN_Init(void)
{
hcan.Instance = CAN1;
hcan.Init.Prescaler = 2;
hcan.Init.Mode = CAN_MODE_NORMAL;
hcan.Init.SyncJumpWidth = CAN_SJW_1TQ;
hcan.Init.TimeSeg1 = CAN_BS1_10TQ;
hcan.Init.TimeSeg2 = CAN_BS2_1TQ;
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();
}
uint16_t StdIdArray1 [4] = {0x581, 0x582, 0x583, 0x584}; // 0x58x ID Series
uint16_t StdIdArray2 [4] = {0x4A1, 0x4A2, 0x4A3, 0x4A4}; // 0x4Ax ID Series
uint16_t mask, tmp, i, num;
sFilterConfig.FilterBank = 5;
sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK; // Mask Mode
sFilterConfig.FilterScale = CAN_FILTERSCALE_16BIT; // 16 Bit
sFilterConfig.FilterIdLow = StdIdArray1[0] << 5; // Filter Id Low
mask = 0x5ff;
num = sizeof (StdIdArray1)/sizeof (StdIdArray1[0]); // Mask code
for (i = 0; i <num; i ++)
{
tmp = StdIdArray1[i]^(~StdIdArray1 [0]);
mask &= tmp;
}
sFilterConfig.FilterMaskIdLow = (mask << 5) | 0x10; // Filter Mask Id Low
sFilterConfig.FilterIdHigh = StdIdArray2[0] << 5; // Filter Id High
mask = 0x4ff;
num = sizeof (StdIdArray2)/sizeof (StdIdArray2[0]); // Mask code
for (i = 0; i <num; i ++)
{
tmp = StdIdArray2[i]^(~ StdIdArray2[0]);
mask &= tmp;
}
sFilterConfig.FilterMaskIdHigh = (mask << 5) | 0x10; // Filter Mask Id High
sFilterConfig.FilterFIFOAssignment = 0; // FIFO 0
sFilterConfig.FilterActivation = ENABLE;
sFilterConfig.SlaveStartFilterBank = 14;
if (HAL_CAN_ConfigFilter(&hcan,&sFilterConfig) != HAL_OK)
{
Error_Handler();
}
if (HAL_CAN_Start(&hcan) != HAL_OK)
{
Error_Handler();
}
if (HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO0_MSG_PENDING) != HAL_OK)
{
Error_Handler();
}
}
static void MX_GPIO_Init(void)
{
__HAL_RCC_GPIOD_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
}
/* Receive Callback. Get messages from the CAN bus analyzer */
void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
if (HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &RxHeader, RxData) != HAL_OK)
{
Error_Handler();
}
if (HAL_CAN_ActivateNotification(hcan, CAN_IT_RX_FIFO0_MSG_PENDING) != HAL_OK)
{
Error_Handler();
}
}
void Error_Handler(void)
{
}
void assert_failed(uint8_t *file, uint32_t line)
{
}
Screenshots:
Case 1:
ID= 581; DLC= 8;
enter image description here
Case 2:
ID = 581; DLC=6;
enter image description here
Case 3:
ID= 581; DLC=2;
enter image description here
Case 4: (Issue)
ID = 581; DLC=4;
enter image description here
Case 5: (Issue)
ID= 4A1; DLC=4;
enter image description here
This issue is only with data byte of length 4. It could be of great help if someone can help me resolve this!