We are using the Jetson Nano and we are having some very unstable issues
What we are using the board for is to tie in 4 photo eyes.
We have designed a board and we are pretty confident in our board.
We have a 12 volt power supply on the Sigma Board that is powering the photo eyes, this is an isolated power supply that is only used for the photo eyes.
Our board connects to the Nano as follows, and please note we have tried various pins on the Nano and have had similar unstable results.
Pin 1 3.3 pin 1
Pin 39 GND Pin 39
Pin 29 GPIO A Pin 12
Pin 7 GPIO B Pin 38
Pin 33 GPIO C Pin 40
Pin 32 GPIO D Pin 35
On the Sigma board, we are doing the following for each port
We have a 1K Pullup resistor
We have a relay Omron G3VM-31DR https://assets.alliedelec.com/v1580814023/Datasheets/6d625c28730683987544fd81220783f5.pdf
We have a 1K current limiting resistor that is used so we don’t burn up the diode.
We have written our program that simply reflects when the pin changes to High (we call it Rising) and when it goes Low and we call it Falling. This code is written in C# using .NET Core 3.1 and the Microsoft System.Device.Gpio 1.0.0 library It’s published for ubuntu-arm64.
What we are seeing is the following
GPIO A seems to always work
GPIO D seems to always work
GPIO C seems to partially work however a lot of times it will just Fall or it will Fall and show the other pins reacting as well.
GPIO B Seems to never work. When we introduce B we see results for ACD along with B. It makes the system very unstable. If I have A and D working and I introduce B (by plugging the photo-eye in or even the wire connecting 7 to 12
It is as if the pins will latch and not release. If you give them a minute they seem to release.
If I just use A and D it will work great
With C or B in the mix it will eventually reboot the Nano.
We have changed B from pin 31 to pin 7 and it acts the same Instable way
I would also like to add that we started out wanting to use pins: 12 , 35 , 38 , 40
When we use these pins , after just a few events the Jetson Nano hard crashes and resets.
Also when I monitor these IO pins with an oscilloscope the outputs switch only from approximately 1.5 volts to ground each time I trigger the banner sensor and occasionally switch from 3.3v to ground very cleanly the way I would expect.