why gpio435 cat value is 1 when pulled down by a 10k resistance external on my carrier board

Autonomous Vehicles DRIVE PX 2 DRIVE Hardware
1

Hi,All
when I want the pin I2C_CAM_DAT(D6/GPIO3_PO.03)，number is gpio435,use as a gpio input.
As I understand,I change the register by sudo devmem2 0x230010 w 0x1042, it will be configured as a input gpio.
And I have a 10k pull down external on my carrier board,so I should get 0 when cat the gpio435 value.
But the truth is I only get 1 in the gpio,and the measuring voltage is 1.65V.
What’s the problem with this?
Thank you very much for your reply!

2

Hi, as you know there is pull-up resistor in module for I2C lines, please do not use it as GPIO.

3

What is the value of the up-pull resistance? 10k already should be able to pull down it.

4

1k ohm

5

why the pull strength is 100k in tht “Jetson-TX2-Generic-Customer-Pinmux-Template”?
Are all the i2C pulled up by 1k?

6

1k is external PU, 100k is internal PU of pin. It is well known that most PU of I2C are 1k or 2.2k.

7

In the “Jetson-TX2-Generic-Customer-Pinmux-Template”
I2C_GP1_DAT(A20) actually have the Ext Pull Up Value (Ω) that is “1k”,but I2C_CAM_DAT(D6/GPIO3_PO.03) is blank, So we thought there is no extra pull up then.