PROCESSOR-SDK-AM335X: Inquiry about GPIO pullup / pulldown disabling setting

Takayuki Miyazaki

Part Number: PROCESSOR-SDK-AM335X
Other Parts Discussed in Thread: AM3356

Hi Experts,

Our customer is developing their system with AM3356 (Processor Linux SDK), customer would like to know how to use GPIO (as INPUT) without pullup/pulldown.

On their system board, AM3356’s gpio2_3 connects to other device with pullup resister , like the attached file(GPIO_pulldown.pdf).

Customer tried to set PULLUDEN bit to “1” (Pullup/pulldown disabled) on “Pad Control Registers”, however, this issue was not resolved yet.

I noticed the following E2E thread , I could not find exact solution.

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1000187/processor-sdk-am335x-how-to-enable-pull-up-on-gpio-line-on-ti-am33xx-soc-within-device-tree/3695066?tisearch=e2e-sitesearch&keymatch=GPIO%20pulldown#3695066

Can I have your Expert’s advice/comments on this, please?

Best regards,

Miyazaki

over 3 years ago

0 Bin Liu over 3 years ago

TI__Guru**** 168611 points

Hi Miyazaki-san,

Can you please explain how exactly the PULLUDEN bit is set? What is the value of the pad control register for gpio2_3?

0 Takayuki Miyazaki over 3 years ago in reply to Bin Liu

TI__Genius 10120 points

Hi Bin,

I’m asking customer how the PULLUDEN bit is set, however, it seems customer noticed other problem for this behavior. I mean, there is possibility that pullup voltage is not enough. Now, customer is investigating it now. I’d like to wait their feedback.

Best regards,

Miyazaki

+1 Takayuki Miyazaki over 3 years ago in reply to Takayuki Miyazaki

TI__Genius 10120 points

Hi Bin,

I received customer's feedback now. Customer was able to resolve this behavior after changing pullup resistance.

Thank you for your help, I'd like to close this ticket.

Best regards,

Miyazaki

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PROCESSOR-SDK-AM335X: Inquiry about GPIO pullup / pulldown disabling setting