TMS320F28030 GPIO CHANGES STATE DURING DEBUG SINGLE STEPPING

Tom Meyers55

Other Parts Discussed in Thread: TMS320F28035

I notice in Debug mode that when I step through certain IQ math statements a GPIO pin is reset to 0 (GPIO8). We would not even have know about this 9except a relay is attached to GPIO8 and we can hear the relay click off.

Single stepping through this statement for instance will set GPIO8 low.

temp = _IQ18(ac_peak_avg); // temp is type _iq18, ac_peak_avg is type long.

Has anyone ever heard of anything like this? Totally repeatable. Happens every time.

If I single step through the Assembly code instead I don't see the pin become reset only single stepping at the C level makes it happen. It does not appear to happen in normal run mode (that we know of).

CCS Version: 6.1.2.00015 TMS320F28035.

over 9 years ago

0 Lori Heustess over 9 years ago

TI__Guru* 93800 points

A step of a C statement will take interrupts whereas a single step of assembly will block interrupts. I suggest checking if there is an interrupt pending before you step and if so, does this interrupt change the value of the GPIO?

0 Tom Meyers55 over 9 years ago in reply to Lori Heustess

Prodigy 60 points

Thanks Lori, We had the same thought. However we have interrupts during stepping turned off and an active breakpoint in our one and only interrupt and it never gets hit.

0 Lori Heustess over 9 years ago in reply to Tom Meyers55

TI__Guru* 93800 points

Ok something else to check, and to rule out, is to see if the device is somehow getting reset. Can you monitor the reset pin to see if it toggles?

0 Tom Meyers55 over 9 years ago in reply to Lori Heustess

Prodigy 60 points

Great idea! I might not get to it today but I will check that in the next few days.

0 Lori Heustess over 9 years ago in reply to Tom Meyers55

TI__Guru* 93800 points

Hi Tom - I wanted to see if the issue was resolved and I can close the thread.

Thank you
Lori

0 Tom Meyers55 over 9 years ago in reply to Lori Heustess

Prodigy 60 points

Hi Lori, I just checked the XRSn pin and it does not change state when the GPIO8 pin gets set low during single stepping.

You can go ahead and close the thread however.

Tom

0 Lori Heustess over 9 years ago in reply to Tom Meyers55

TI__Guru* 93800 points

Thank you for the feedback, Tom. Did you find another cause/solution?

Regards
Lori

0 Tom Meyers55 over 9 years ago in reply to Lori Heustess

Prodigy 60 points

Hi Lori,

We kind of think it is something peculiar to the GPIO8 pin. Other pins we are using do not change state. Only GPIO8 changes state ( high to low, and only when we are single stepping through certain IQ math functions). So in our next pass we are going to move that control function to a different GPIO pin. Its not a big issue for us. More of a curiosity. We would not even have discovered it if it was not controlling a relay. We can hear the relay toggle when we are single stepping and hit an IQ math function.

Tom..

0 Lori Heustess over 9 years ago in reply to Tom Meyers55

TI__Guru* 93800 points

hmm very odd. Let me know if you find something! I am very curious now.

-Lori

0 Tom Meyers55 over 9 years ago in reply to Lori Heustess

Prodigy 60 points

I surely will...

Tom

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TMS320F28030 GPIO CHANGES STATE DURING DEBUG SINGLE STEPPING