Systick time missing

[SRedd.5]

I am running the motor control workbench B-G431B-ESC1 board. The systick fires at every 2K frequency as per the user manual and the waveform matches when i toggle, but the problem is sometimes it misses as shown

I want to debug and find out why it misses those timings in between. Please suggest how do i find out? I am also running CAN in parallel at 500KBPS.

[Karl Yamashita]

You need to exit the systick quickly when it interrupts so other interrupts can fire, as well as the systick itself. In your systick, set a flag. In a main while loop check the flag and then call your 3 tasks

MC_RunMotorControlTasks();
CAN_Task();
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_12);

[SRedd.5]

I have tried this once but seem to be complete misbehavior, i will try again.

[Johi]

, I still wonder if you have reflected on the thought of driving your I/O directly with a timer unloading your MCU and guaranteeing timing as per hardware? ARM/STM32 is designed for that approach and then you are 100% sure that timing is correct. If it takes too much time to solve the issue using interrupt priorities and the like, then for sure you risk that your final solution will not have maximal robustness as environmental conditions can vary. You can change frequency and duty cycle from your main loop but leave the heavy lifting to the hardware timer driving the I/O.

[SRedd.5]

I have to study about this i never done it before. I will give a try.

[Johi]

See below example for 1 Hz, you should be able to to take it from there.

[SRedd.5]

The problem is it is motor control application so i use all the PWM channels, hence i cannot use the method you suggested for driving the GPIO's.

[SRedd.5]

I modified the algorithm of CAN and behavior is ok now, i mean i transmit 3 messages at one time, after 1 sec another 3 messages with total of 12 messages

1st sec -> 3messages

2nd sec -> 3 messages

3rd sec -> 3 messages

4th sec -> 3 messages

repeat like this.