Voltage level of GPIOs

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX1
1

Hello.

I have a LED lighting circuit using Tegra X1 GPIOs. (Lighting when low output.)
I’m observing GPIO voltage level until boot kernel.

  • GPIO16_MDM_WAKE_AP(GPIO_PX0)
  • GPIO8_ALS_PROX_INT(GPIO_PX3)

Both pads are measured voltage 0V until boot kernel.
But I expect they are 1.8V.
(according to JetsonTX1_OEM_Product_DesignGuide_20170912.pdf, they are internal pull-up)

Please give me advice:

  1. Why 0V in spite of internal pull-up?
  2. Are there pads which is set as GPIO at power-on? If yes, which pad?
  3. I think it is correct to be written about default register value in Tegra_X1_TRM_DP07225001_v1.2p.pdf. Is it right?

Regards.

2

Hi, please check the pinmux sheet to select the GPIO which pin state of POR is ‘pu’.[url]http://developer.nvidia.com/embedded/dlc/jetson-tx1-module-pinmux[/url]