how to set long delay with use of timer(like up to 5 minute,)

[dbgarasiya]

part number: STM32F779BI

I am using clock frequency 108 MHz ( not system clock , system clock is 216 MHZ)

I don't want to use loop

if not possible what is the maximum value i could set using timer

[dbgarasiya]

@turboscrew​  that is also not getting 10 milliseconds of timer

[berendi]

Are you going to tell how long is it then, or do we have to guess?

[dbgarasiya]

it is appoximately 333 us of timer with this configuration .

while (1)

{

HAL_Delay(1000);

Timer6_Read();

//Read_All_Timers();

}

i have written my code as above for reading timer count

terminal screenshot i have attached with this post

[turboscrew]

In that case, check your clock tree.

[dbgarasiya]

I have used timer 6 which is clocked by timer clock register is RCC_APB1ENR

like this

RCC->APB1ENR |= (1<<4);  // timer 6 which is 108 MHz

i am attaching you my clock configuration sceenshot for this, so you will get better ide about this

[berendi]

How do you know that it's 333 us?

How long takes Timer6_Read to execute, how did you measure it?

How did you verify that the timer didn't overflow?

How did you verify the system clocks?

How did you verify HAL_Delay accuracy?

What do RCC and TIM6 registers contain?

[dbgarasiya]

I am attaching you 2 sceenshot of configuration of register

1. RCC register after timer clock configuration
2. Timer register after initialization and before reading timer value

Dipak Garasiya

[turboscrew]

Yes. Tim6 frequency should be 108 MHz before prescaler. With prescaler 107 the timer should have 1 MHz count frequency (1 us period).

With 9999 as the ARR the counter should wrap around every 10 000 us = 10 ms.

BTW, which timer does HAL use? Tim7?

Also, you read the timer6 after HAL_Delay(1000), but where do you start the timer6 (or reset it)?

It should happen right before HAL_Delay, or the while before it (it shouldn't get too much off that quickly).

If the clock really runs that wrong, I'm running out of ideas.

I manually checked the clock configurations, and the only wrong thing was that PLLR was zero (bits 30-28 of PLLCFGR), when it should have been at least 2 (says the reference manual). In the clock tree it looks like it should be 2, but in the register it seemed to be 0.

[dbgarasiya]

I have check my clock frequency ,it is perfactly ok

system clock = 216 MHz , hclk clock = 216 MHz ,PCLK1= 54 MHz and PCLK2 = 108 MHz

eventhough it is not gettting 10 ms of delay

[turboscrew]

What I mean is that maybe tim6 has already counted so far before you start the HAL_Delay that it wraps during that delay.

Try writing zero to timer6 CNT-register just before the while-loop.

Also, what does that timer6 reading function do? If it uses printf, that may take milliseconds.

Rather, make a for-loop and make a small table of read values. Then check the table after the loop.