TMS320F28379D: Strange GPIO behavior in TMS320F28379D

Kevin Bachovchin

Part Number: TMS320F28379D

Hello,

I have the following very simple code

GpioDataRegs.GPADAT.bit.GPIO21 = 1;
GpioDataRegs.GPADAT.bit.GPIO20 = 1;
GpioDataRegs.GPADAT.bit.GPIO19 = 1;

GPIO19 and GPIO21 get set high. However for some reason, GPIO20 is not getting set high. (I see this both when I look at GPIO20 with a scope and when I look at the GpioDataRegs in the Registers tab in the Code Composer Studio debugger.)

What makes this even stranger is that if I change my code to:

GpioDataRegs.GPADAT.bit.GPIO21 = 1;
GpioDataRegs.GPADAT.bit.GPIO19 = 1;
GpioDataRegs.GPADAT.bit.GPIO20 = 1;

Then GPIO21 and GPIO20 get set high, but not GPIO19. So it seems like whatever one I have in the middle is not getting set.

However, if from the Registers tab in Code Composer Studio, I manually set all three high, then all three go high and remain high (both in the debugger and on the scope).

I'm at a loss to explain this weird behavior. Am I missing something simple or is it possible that the TMS320F28379D chip is damaged?

I am setting the GpioCtrlRegs to outputs in my code.

EALLOW;
GpioCtrlRegs.GPADIR.bit.GPIO21 = 1;
GpioCtrlRegs.GPADIR.bit.GPIO20 = 1;
GpioCtrlRegs.GPADIR.bit.GPIO19 = 1;
EDIS;

I've tried recycling power to the microcontroller, restarting Code Composer Studio, and restarting my computer. The same behavior persists.

Thanks,

Kevin

over 4 years ago

0 Kevin Bachovchin over 4 years ago

Expert 1060 points

Just tested on another board with another TMS320F28379D MCU and I'm seeing the same behavior. So it must be some software issue even with such simple code. What am I missing??

0 Vivek Singh over 4 years ago in reply to Kevin Bachovchin

TI__Guru** 115411 points

Hi Kevin,

You need to use the SET/CLEAR or TOGGLE register to change the GPIO pin state. That should fix the issue you are observing.

Regards,

Vivek Singh

0 Vivek Singh over 4 years ago in reply to Vivek Singh

TI__Guru** 115411 points

You can refer this post to understand the issue in detail.

Regards,

Vivek Singh

0 Kevin Bachovchin over 4 years ago in reply to Vivek Singh

Expert 1060 points

Vivek,

Thank you for your helpful reply. I understand the issue now from reading the link.

I want to force low/high a bunch of GPIOs depending on user input for each GPIO. Is there any more elegant way to use the set/clear than with if/else statements?

When using GPADAT, I could do one simple line of code for each GPIO

GpioCtrlRegs.GPADIR.bit.GPIO21 = UserGPIO21Control;   //force GPIO21 high or low depending on UserGPIO21Control

Now when using SET/CLEAR, I need an extra if statement for each GPIO

if (UserGPIO21Control == 0)
{
    GpioDataRegs.GPACLEAR.bit.GPIO21 = 1;  //force GPIO21 low
}
else
{
    GpioDataRegs.GPACLEAR.bit.GPIO21 = 1;  //force GPIO21 high
}

This would not be a big deal with just one GPIO, but I have a bunch of GPIO I need to force low/high depending on user input, so I'm just wondering if there is a better way to do this than with a bunch of if/else statements.

Thanks,

Kevin

0 Kevin Bachovchin over 4 years ago in reply to Kevin Bachovchin

Expert 1060 points

Vivek,

Just wanted to follow up on this since I haven't gotten a reply: For setting GPIOs based on user input, is there any more elegant way to use the set/clear than with if/else statements?

Thanks,

Kevin

0 Vivek Singh over 4 years ago in reply to Kevin Bachovchin

TI__Guru** 115411 points

Hi Kevin.

I think you need to write it like this for user input based pin toggle.

Regards,

Vivek Singh

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TMS320F28379D: Strange GPIO behavior in TMS320F28379D