If input 1.xV to Jetson Xaveir GPIO(GPIO17/GPIO35), the input read value is not stable as 0?

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
#1

Hi NV_Team,

We use GPIO17/GPIO35 as input on Jetson Xavier(software configure it as input gpio, and pull-down ).
If we input 0.6V signal to these gpio, it stays low stable.
If we input 3.3V signal to these gpio, it stays high stable.
But，
If we input 1.xV (such 1.0V) signal to these gpio, then read this pin 1 or 0, not stay in 0.
If we input 2.xV (such 2.3V) signal to these gpio, then read this pin 1 or 0, not stay in 1.

Why this happend? We want a stable state of the gpio input, whatever the input voltage changes.

root@xavier:/sys/class/gpio# cat /sys/kernel/debug/gpio | grep '417'
 gpio-417 (GPIO17              |sysfs               ) in  lo     
root@xavier:/sys/class/gpio# cat /sys/kernel/debug/gpio | grep '417'
 gpio-417 (GPIO17              |sysfs               ) in  hi    

root@xavier:/sys/class/gpio# cat /sys/kernel/debug/tegra_pinctrl_reg|grep 'pq1'
Bank: 0 Reg: 0x02430058 Val: 0x00000056 -> soc_gpio21_pq1

HW: Jetson Xavier Devkit
SW: L4T-R32.5
GPIO: Jetson-GPIO

#5

It seems there’s inconsistence state changes with input voltage to GPIO, we’re investigating it.

#8

Hi Luna,
This is expected! Since these pins go from level shifter, high output voltage range is ~3.28V. Any value above it will give valid logic high signal value. Similary for low range of ~0V only. If you want high level on 1.8V then change the jumper J514 position from 1<->2 to 2<->3. It will show logic high on 1.8 V and low on 0V.

Thanks,
Shubhi

#9

Hi Shgarg,

Thanks for your information, we got it.