I created a timer using xTimerCreateStatic(), setting period to pd_MS_TO_TICKS(500). Then later I started the timer with xTimerStartFromISR and found that the timer callback function was immediatelly executed. I changed to using xTimerChangePeriodFromISR, setting period (again) to pd_MS_TO_TICKS(500…

Is that intended behavior? No [ refer ]: … if the timer is not stopped, deleted, or reset in the mean time, the callback function associated with the timer will get called 'n 'ticks after xTimerStart() was called, where ‘n’ is the timers defined period. … What FreeRTOS port/ HW arch are you usin…

Hello tony josi, I read these lines too, but found something else, thats why I ask. I am working with STM32G0B0 = ARM Cortex M0+ and FreeRTOS 10.5.1. I think interrupt priorities don’t play a role here (??). I don’t have configMAX_SYSCALL_INTERRUPT_PRIORITY defined. I found out by sending a mess…

I don’t know about intended behavior, but it is explainable behavior that xTimerStartFromIsr() and xTimerResetFromIsr() behave as you observed in tickless idle. The forum has a couple of different threads that explain. Here is a good one where I managed to save all of humanity: [image…

Another one. Although the diagram no longer looks right (in my browser at least). [image] xTimerStartFromISR() and xTimerResetFromISR() with tickless idle Kernel When used with tickless idle, xTimerStartFromISR() and xTimerResetFromISR() might not behave as expected. For…

Hi Jeff, thanks for your answer and the info, I hope to keep it in mind. Yes, I’m fine with xTimerChangePeriodFromISR. Martin

It does seem a little odd to have to call xTimerChangePeriodFromISR(). Since this issue has come up a couple of times, here’s a possible fix for combining tickless idle and xTimerStartFromISR(). Add option to defer start/reset timer from ISR …

Which is the right way to start a one-shot timer?

Kernel

jefftenney (Jeff) April 27, 2023, 2:14pm 5

Another one. Although the diagram no longer looks right (in my browser at least).

Topic		Replies	Views
xTimerStartFromISR() and xTimerResetFromISR() with tickless idle Kernel	2	1056	January 19, 2021
xTimerChangePeriodFromISR overhead? BUG? Kernel	6	270	June 21, 2018
Timer callback executes immediately after start/reset of timer Kernel	10	1825	November 11, 2022
xTimerResetFromISR do not restart the timer period properly Kernel	6	236	July 23, 2014
xTimerChangePeriod consistently adds one tick of delay Kernel	6	414	February 23, 2023

Which is the right way to start a one-shot timer?

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