TMS320F28069: GPIO output unexpected high level during power on

Wiky Liao

Intellectual 2000 points

Part Number: TMS320F28069

Tool/software:

Hi Expert,

I am following this case at this E2E thread: https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1517045/tms320f28069-97-pin-output-unexpected-high-level-with-power-on?tisearch=e2e-sitesearch&keymatch=97%20pin%20output%20unexpected%20high#

Customer build a new board and use another GPIO, however the issue still present, even F28069 launch pad can repeat this issue.

Customer need to secure the output keep LOW during power up, so they add pull down resistance but still make it LOW. As previous mentioned,

11k pull down resistor will have 2V, and 2k pull down resistor will have 1.3V. We can't pull down resistance less than 2k in application.

Could you help to provide solution how to make F28069 output Low during power on? thanks.

Best Regards.

Wiky

5 months ago

0 Prarthan Bhatt 5 months ago

TI__Genius 14125 points

Hi,

As mentioned in the earlier thread - "For this device, seems it is necessary to use other GPIO that doesn't exhibit this behavior if you need to route to driver. This GPIO can be used for other GPIO where high signal doesn't impact board such as communication"

Thanks

0 Wiky Liao 5 months ago in reply to Prarthan Bhatt

TI__Intellectual 2000 points

Hi Bhatt,

Actually we already use other GPIO but seems have the same issue. Could you guide me which GPIO can solve this issue?

0 Prarthan Bhatt 5 months ago in reply to Wiky Liao

TI__Genius 14125 points

Hi,

You mean to say that all GPIO show such behavior (go high) on power up ?

Thanks

0 Wiky Liao 5 months ago in reply to Prarthan Bhatt

TI__Intellectual 2000 points

Hi Bhatt,

Yes, so far we don't find a workable IO pin that address this issue. Could you help to do bench test to verify? thanks.

Wiky

0 Prarthan Bhatt 5 months ago in reply to Wiky Liao

TI__Genius 14125 points

Hi,

I tried it on launchpad but there it seems like the power up sequence is not followed properly.

As in the 3.3V are provided to JTAG pins before the XRSn comes up. Can you confirm if the device pins are not powered before XRSn comes up?

Thanks

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TMS320F28069: GPIO output unexpected high level during power on