CAN frame monitoring problem in loopback mode

[Erwan03]

@SofLit hello again,

So , i am facing a problem to display the frame i am supposed to send from CAN_Tx pin in loopback mode. I am using picoscope to display.

Here is the function i wrote to configure the Header, and send the data:

void CAN_send(void)

{

char msg[50];

CAN_TxHeaderTypeDef TxHeader;

uint32_t TxMailbox;

uint8_t TxData[4] = {'T','E','S','T'};

TxHeader.DLC = 4; // 4 data byte

TxHeader.ExtId = 0; // Not used so far

TxHeader.IDE = CAN_ID_STD; // Standard ID

TxHeader.RTR = CAN_RTR_DATA; // Data and not remote frame

TxHeader.StdId = 0x103; // Data ID

TxHeader.TransmitGlobalTime = DISABLE;

if(HAL_CAN_AddTxMessage(&hcan1, &TxHeader, TxData, &TxMailbox)!=HAL_OK)

{

Error_Handler();

}

while( HAL_CAN_IsTxMessagePending(&hcan1, TxMailbox));

sprintf(msg, "Message transmitted\r\n");

HAL_UART_Transmit(&huart2, (uint8_t*)msg, strlen(msg), HAL_MAX_DELAY);

}

In the Main function, i am calling it after the HAL_CAN_Start function. The uart connexion tells me that the frame is sent but i can't see it though.

Thank you again for your precious help!

[SofLit · Accepted solution]

Thank you for the shared main file:

I noticed two issues:

In the timing configuration:

hcan1.Init.TimeSeg1 = CAN_BS1_1TQ;
hcan1.Init.TimeSeg2 = CAN_BS2_8TQ;

And with the filter configuration:

canfilterconfig.FilterBank = 10;
canfilterconfig.SlaveStartFilterBank = 0;

So try these configurations:

 hcan1.Init.TimeSeg1 = CAN_BS1_7TQ;
 hcan1.Init.TimeSeg2 = CAN_BS2_2TQ;

and

 canfilterconfig.FilterBank = 0;
 canfilterconfig.SlaveStartFilterBank = 14;

[Erwan03]

Nothing changed: 

Let me inform you than i got it to work once but several weeks ago and when i added some structures and other functions in order to fit it into a real project then it couldn't work anymore. And the parameters you asked me to change were the same unfortunately.

[Erwan03]

Wait Wait! It works actually.

The debug mode does not allow us to see a frame. Only run mode. Thank you for your help!

Have a nice day!

[SofLit]

Ok.

Could you please share your project so I could test it on one board when I have one on hands? I will do it next Wednesday.

If you couldn't share it on public send it to me by message.

[Erwan03]

It seems that i cannot uplink the whlole project because not all files are supported.

Everything i wrote is in the main.c though. Then please find attached the main.c and .ioc files so you can test it

[SofLit]

---

@Erwan03 wrote:

Wait Wait! It works actually.

The debug mode does not allow us to see a frame. Only run mode. Thank you for your help!

Have a nice day!

---

Nice! You're welcome :smiling_face_with_smiling_eyes: .. But still strange it could not be running in debug mode!

Which Toolchain are you using? I will try it with a NUCLEO-F446RE board when I have one on hands.