GPIO Problem on F28M35H52C1 Cortex M3 (Rev B)

Thomas Brady

Hello,

We are currently using the F28M35H52C1 Rev B. We had used Rev X until this problem started showing up.

I have built a small test program for the M3 (attached). The program simply sets up GPIO Port J pins 6 & 7 as outputs, and toggles them in a while loop. The issue I'm currently seeing is that if one of these pins is low and I pull the other high, it briefly pulls them both high. I am using a logic analyzer to watch the output on the GPIOs.

Test cases:

PJ6 Low, Pull PJ7 High. Result: PJ6 high for a few microseconds then returns low.

PJ7 Low, Pull PJ6 High. Result : PJ7 high for a few microseconds then returns low.

I've verified with a continuity meter that there is no external short between these two pins.

Any direction or insight is greatly appreciated.

Thanks!

Tom

1207.m3gpiotest.c

over 12 years ago

0 Gautam Iyer over 12 years ago

Guru 192875 points

Hi Tom,

Seems unuasual though! What if you remove the forever while loop, do you still observe this behavior?

Regards,

Gautam

0 Thomas Brady over 12 years ago in reply to Gautam Iyer

Prodigy 210 points

Hi Gautam,

Thanks for your attention on this!

I've conducted the test without the infinite while loop and the results were inconclusive. Sometimes pulling up one pin affected the other... whereas other times, there was no effect.

Best,

Tom

0 Gautam Iyer over 12 years ago in reply to Thomas Brady

Guru 192875 points

Tom, such behaviour is unexpected esp. GPIO malfunctioning. If I believe that allz well at your end ie no external hardware causing such GPIO malfunctioning then we've the only choice of getting the kit replaced.

Regards,

Gautam

0 Thomas Brady over 12 years ago in reply to Gautam Iyer

Prodigy 210 points

Hi Gautam,

We've reproduced this error on three chips now, so the issue must either be endemic with the rev b devices or its on our end. We'll know for sure tomorrow when we scope before our level converter, directly at the chip output. We don't anticipate different results since we've used the converter in the same way several times, but we'll verify and post tomorrow.

Best,

Tom

0 Gautam Iyer over 12 years ago in reply to Thomas Brady

Guru 192875 points

Sure TOM, do keep us updated. Yup, do check the voltage levels on your board.

Regards,

Gautam

0 Trey German289 over 12 years ago in reply to Gautam Iyer

TI__Mastermind 22025 points

Tom,

We aren't aware of any issues with the GPIO. It would help if we could isolate this as a software or hardware problem. Would you mind taking a look at the GPIO registers and ensure that each GPIOPinWrite is only effecting the desired bits?

BR,

0 Santosh Athuru over 12 years ago in reply to Trey German289

TI__Mastermind 19810 points

The proper way to toggle a pin without affecting other pins is as below (ex: toggling GPIO6)

GPIOPinWrite(GPIO_PORTJ_BASE, GPIO_PIN_6, GPIO_PIN_6); //pull GPIO6 HIGH

GPIOPinWrite(GPIO_PORTJ_BASE, GPIO_PIN_6, ~GPIO_PIN_6); //pull GPIO6 LOW

can you try doing that in your code?

Best Regards

Santosh

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GPIO Problem on F28M35H52C1 Cortex M3 (Rev B)