CCS/TMS320F28075: SYS/BIOS, Timer Module preemption

Hi Frank,

Try utilizing Hwi_disable() and Hwi_restore().

key = Hwi_disable();
/* Critical Code */
Hwi_restore(key);

Derrick

Hi Derrick:

Last time, I tried using Hwi_disable() and Hwi_enable(), I also does not work, Thanks!

Have a good day!

Frank

Frank,

Is your SPI interrupt service routine managed using the Hwi module?

Derrick

Hi Derrick.

Yes, SPI interrupt service is managed by HWI module. Thanks!

Have a good day!

Frank

Hi Derrick.

If I using Timer_start() and TImer_stop. It works well，Thanks！

Have a good day!

Frank

Frank,

The timer interrupt always uses the Hwi dispatcher as well (The Timer module automatically creates a Hwi instance for the timer interrupt). Given that, Hwi_disable() and Hwi_restore() should prevent your gated SPI code from being preempted.

Both the method of using the GateHwi_enter()/GateHwi_leave and Hwi_disable/Hwi_restore() are valid methods to solve your issue.

It appears you're experiencing unexpected behavior. How are you able to confirm your critical SPI code is being preempted by the Timer interrupt?

Could you share the version of SYSBIOS you're using?

Derrick

Derrick,

Thanks for your reply, test with two global variable, if timer preempte, one variable will plus one. 

I checked again, I am not sure if this below is the cause.

In HWI module as below picture, the default value of the zero letency IER mask is 0x0. The timer use timer0, it correspond to INT1. So I can't use Hwi_disable(). I have not validated. I think that's may be the cause.

another picture from WIKI, that introduce the zero latency IER mask.

Thanks

Have a good day!

Frank

The below picture from TI WIKI 

Frank,

Did you try wrapping your critical code with Hwi_disableIER()/restoreIER() calls to explicitly mask any zero-latency interrupts?

Derrick

Any update on this?

Dear Derrick and ToddMullanix.

Thanks for your help, cause I am not in office these days, I have not validated this, So I have not update at moment. If I do this again, I will tell you results, Thank you very much.

Have a good day!

 Frank

Ok, Thanks!