DietPi with OrangePi Zero3

Hello
I jave installed DietPi on OrangePi Zero3 and i’m trying to make a small weather station.
I am coding in C++ with the use of libgpiod.
The problem I’m facing is reading the SHT31 humidity sensor that I connected to i2c-3 (pins 3&5 on the 26 pin connector.
The thing is that i2c-3 is not available under /dev
Does anyone have an idea how to fix this or is there any other i2c porta that are broken out to the “world”.
There is no i2c 0 or 1 available pins
Thank you

Did a bit o’ DDGing
Found this
https://www.reddit.com/r/OrangePI/comments/17itw1p/enable_i2c3_on_orange_pi_zero_3_raspbian/

it looks as though there was supposed to be a modified version of raspi-config on that image, but for some reason it was the stock one. With a little digging, I found a copy of the one off the opizero 2 and was able to reverse engineer how they did things. There is a /boot/orangepiEnv.txt and a /boot/dtb directory with orange-pi specific device tree files in it. But they don’t seem to be configured normally and are just called without parameters on a single ‘overlays=’ line separated by &.
So doing overlays=ph-i2c3 seemed to get the bus working.

I also found this but for me it does not work. I will comment on this redit post for detalis
Tnx

Ok so after some digging I got it to work. The instructions posted on github (that this readit post and google lead to) are wrong.
There it is said that you need to put

overlays=ph-i2c3

In /boot/armbianEnv.txt or /boot/dirtpiEnv.txt

But the correct way is

overlays=i2c3-ph

Anyway leaving this here for someone else struggling with this

3 Likes

Nice…it seems a guy worked up a patch for it as well
After doing some DDG’ng the i2c3-ph

Very nice find though!!!