STM32F042G6U CAN - Can't receive frames

[YannDiPadova]

Hello,

I have an issue with the CAN bus on STM32F042G6 µC. 

For the moment I just want to receive Frames from an other controller (STM32G0B1) and it doesn't work at all.

I am using PA11 as Rx Pin and PA12 as Tx Pin Pins.

Here is the configuration part with a 12MHz external clock :

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 = 16;
 hcan.Init.Mode = CAN_MODE_NORMAL;
 hcan.Init.SyncJumpWidth = CAN_SJW_1TQ;
 hcan.Init.TimeSeg1 = CAN_BS1_1TQ;
 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();
 }
 /* USER CODE BEGIN CAN_Init 2 */

 /* USER CODE END CAN_Init 2 */

}

 I tried to read the frame sent with this code :

int main(void)
{
 HAL_Init();

 SystemClock_Config();

 MX_GPIO_Init();
 MX_CAN_Init();

 if(HAL_CAN_Start(&hcan) != HAL_OK)
 Error_Handler();

 if (HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO0_MSG_PENDING) != HAL_OK)
 {
	Error_Handler();
 }

 while (1)
 {
	 HAL_Delay(500);
 }
}

I don't understand why but it is impossible for me to go in the HAL_CAN_RxFifo0MsgPendingCallback function when a message is received. I checkes the RX Pin with an oscilloscope and the CAN frame is correct on this Pin.

 

I already found this topic https://community.st.com/t5/stm32-mcus-products/stm32f042g6ux-can-issue/td-p/675078 and follow what was said but nothing works. I don't have any filters, I enabled interrupts for CAN on NVIC menu and in CAN menu. My Rx pin is set to Pull-Up and both my µC have the same exact configuration.

 

I send a the configuration of my CAN, NVIC and GPIO in .ioc file on attached image.

 

Do you have any idea why it doesn't work ?

 

Thank you in advance for your reply,

Yann Di Padova

 

[Andrew Neil]

Please give hardware details - see: 

How to write your question to maximize your chances to find a solution

[YannDiPadova]

Hello, I'm using a STM32F042G6U6.
I'm also using STM32CubeIDE with STM32Cube MCU Package for STM32F0 : Version 1.11.5

 

My other µC used to send the frames is a STM32G0B1CBU6

 

In attachment, here's my hardware connection. CAN TX is directly connected to PA12 and CAN RX to PA11

 

[mƎALLEm]

Hello,

At a first glance:

These are bad timing parameters:

 hcan.Init.TimeSeg1 = CAN_BS1_1TQ;
 hcan.Init.TimeSeg2 = CAN_BS2_1TQ;

You need to increase BS1 and BS2 as much as possible with a sample point at 87%.

I invite you to use this web tool for CAN timing computation: http://www.bittiming.can-wiki.info/.

I also recommend to read these articles:

Using CAN (bxCAN) in Normal mode with STM32 microcontrollers (Part 1)

Using CAN (bxCAN) in Normal mode with STM32 microcontrollers (Part 2)

[YannDiPadova]

Thanks, I will try and come back to you if it works (or if it doesn't)