Pinmux configuration to change the logic level to 3.3 volts

[wallybeam]

Hello, I have a Jetson Orin Nano Devkit. I edited the pinmux configuration to make board pins 12, 18, 22, 23, 26, 33, 19, 32 bidirectional. When I set the pins to High, I measured 1.6 volt in between ground of the board and High output.

My question is shouldn’t this be equal to 3.3 volt instead? Before using a multimeter I used leds to test. By doing so did I change the logic level ? So is there a fail safe feature to reduce output power?

Finally, is there a function to activate TXB0108 level shifter in pinmux table?

[KevinFFF]

Hi wallybeam,

What’s the Jetpack version in use?

@wallybeam

I edited the pinmux configuration to make board pins 12, 18, 22, 23, 26, 33, 19, 32 bidirectional.

Do you mean the pins from 40-pins expansion header on the devkit?

@wallybeam

When I set the pins to High, I measured 1.6 volt in between ground of the board and High output

Could you get a scope instead of using multimeter to check its actual signal?

How did you control it High? Please share the commands you used for further check.

[wallybeam]

I am using Jetpack 6.2 the device is Jetson Orin Nano Super devkit. Yes, I mean 40-pins expansion headers.

I will try the scope as well but for comparison the Jetson Orin Nano devkit with Jetpack 5.1.2.

I couldn’t use the scope yet. I am using Jetson.GPIO module.

Here is what I did:

import Jetson.GPIO as GPIO
GPIO.setmode(GPIO.BOARD)

GPIO.setup(10, GPIO.OUT)
GPIO.out(10, True)

Here is how I configured that pin as biderectional. I just noticed 3.3 volt tolerance parameter. I am setting it to Enable and reflashing the device now.

Update:
I from the 40-pins extansion board the number 36 (I found out that it’s GPIO3_PR.05) doesn’t have that function. When I measure the output voltage of pin 36, it’s equal to 1.5 bolt with multimiter. Probably, it will be equal to 1.8 with scope:

[KevinFFF]

I would suggest you using scope to check if it is stable 1.6volts or a wave due to SFIO bit enabled.

@wallybeam

I from the 40-pins extansion board the number 36 (I found out that it’s GPIO3_PR.05)

Yes, the PIN36 from 40-pins expansion header is PR.05 as following.

Could you try to configure it as GPIO3_PR.05/Bidirectional/Drive 1 in pinmux spreadsheet and measure its signal after boot up?

[wallybeam]

Thanks for the suggestions. It’s default output is 3.3 volt, indeed. However it’s fluctuating and if I connect a load like LED,the output becomes 1.8 volt (or 1.6 volt depends on the measurement method).

[sgursal]

@sgursal

What you seem to be measuring is the forward voltage drop of the LED. Please check the output voltage without LED.

What you seem to be measuring is the forward voltage drop of the LED. Please check the output voltage without LED and with scope, if possible.