CAN Cyclic Frame with 100ms using a timer

Forum|Forum|11 months ago
March 9, 2025
4 replies
1749 views

Hi everyone,
I'm using the STM32F407 for CAN Communication with the Loopback Mode. I'm trying to send a cyclic frame using a timer.
I'm using the timer2 with a clock of 84MHz (APB1), a prescaler of 8399 so i will have a tick every 1ms and a period of 1000 - 1 because i need a cyclicity of message sending every 100ms.
I only get the data transmitted to the RxData by calling CAN_Rx_Callback(&hcan1); in the main function.
This way, i'm not sure if i'm sending data every 100ms or i'm sending data all in once.
How can i update my code to resolve this problem.

This topic has been closed for replies.

Best answer by mƎALLEm

Hello,

By testing your configuration and by adding a pin that toggles inside the timer interrupt, it seems the timer callback is firing each 100ms (PD0 is toggling):

void HAL_TIM_PeriodElapsedCallback (TIM_HandleTypeDef *htim){
	HAL_GPIO_TogglePin(GPIOD, GPIO_PIN_0);

//	if (htim->Instance == TIM2){
//		CAN_SendMessage();
//	}
}

So I don't know how you did conclude that the interrupt is firing each 1ms?

I'm attaching the project for your reference.

PS:

1- you are using HSI as a source clock for CAN communication. It's OK when you are in loopback mode but when you move to Normal mode you need to use the external crystal.

2- No need to call the CAN callback in main(): CAN_Rx_Callback(&hcan1);. It's managed by interrupt.

Hope I've answered your question.

M

mƎALLEm

Technical Moderator

Hello,

This is a timer related question. So for now forget about CAN communication and try to generate a periodic timer interrupt with 100ms of interval.

You need also to attach your ioc file as others can help you efficiently.

A

AzizzAuthor

Graduate II

Hello,

Thank you for your response. Here is my .ioc file for reference. Let me know if you have any feedback or if I should make any modifications.

J

Javier1

Graduate II

This is a community, engage in a conversation, maybe people will help you along the debugging way.
if you just drop your broken code for others to fix maybe youll be better hiring a freelancer
https://www.fiverr.com/gigs/stm32

If it was up to me ill try toggle a LED each 100ms , if you own an osciloscope try sniffing those CANbus lines.
If you dont try getting one of these CAN-USB, great tools