Problem with timers in Sys/Bios - only timer 2 works

Jacek Jawski

Other Parts Discussed in Thread: SYSBIOS

Hi,

I wanted to set dynamicallly a basic configuration of timer4 on IDK AM437X with sysbios 6.42.3.35. After starting BIOS, in one of the tasks, I put the following code:

Error_init(&eb);
Timer_Params_init(&timerParams);
timerParams.period = 1000000; /*1s*/
timerParams.periodType = Timer_PeriodType_MICROSECS;
timerParams.arg = 1;
timerHandle = Timer_create(4, tickFxn, &timerParams, &eb);
Timer_start(timerHandle);

Function tickFxn was responsible for toggling LEDs. The thing is that the code above doesn't work but it works fine when the first of the timer_create parameters is Timer_ANY. I've tried all the available timers and I figured out that only TimerId=2 works. All the examples in handbooks or E2E show the configuration for Timer_ANY parameter - so is there any additional setting/register I should configure when specyfing the timer?

Regards,

Jacek

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

I will ask the ISDK team to comment.

0 Jacek Jawski over 9 years ago in reply to Biser Gatchev-XID

Intellectual 270 points

Hi,

One important thing is that for all the timers (except for #2) the task crashes at the function timer_create(); In details: the _exit(int) is called from syscalls.c when program gets to the Timer_deviceConfig(&tempObj, NULL); function in Timer.c

When I create timers statically in Sys/Bios the results are the same.

I used the program motor_control from sdk/example folder as a basis (with 'commented' unused code), so maybe still something blocks a respective register?

Regards,

Jacek

0 Frank Walzer over 9 years ago in reply to Jacek Jawski

TI__Mastermind 44306 points

Jacek,

that means your timer module is not clocked. Only very few modules on a Sitara device are actively clocked after a reset. Any register access then fails with a data abort. There are quite a few forum entries on the same for AM335x. Sys/Bios does not take care about enabling module clocks and you need to do this manually either in your boot loader or in a function that runs before Sys/Bios starts using the timer. see the startup support in Sys/Bios.

Regards,

0 Afzal MOHAMMED over 9 years ago in reply to Jacek Jawski

TI__Prodigy 635 points

Hi,

Timer module has to be enabled before using it (probably bootloader is enabling timer2), i.e. "PRCMModuleEnable()" has to called on it before using, see "endat_loop_timer_create()" in "sdk/example/endat_diagnostic/endat_app.c" too.

Regards
afzal

0 Afzal MOHAMMED over 9 years ago in reply to Afzal MOHAMMED

TI__Prodigy 635 points

Hi,

Okay Franks's & my reply crossed, in effect same answer.

Regards
afzal

0 Jacek Jawski over 9 years ago in reply to Frank Walzer

Intellectual 270 points

Hi,
Thank you for your response.
All in all, the problem was indeed related to lack of clocking. Now it works fine, however after that try I came back to the settings I wrote i.e. without the PRCMModuleEnable() function - and unexpectedly the timer4 was properly initialized and ready to use - even after reset. Shouldn't that setting be erased during reset?

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Problem with timers in Sys/Bios - only timer 2 works