I2c overlay for armbian on radxa zero 2w

I am connecting a radxa zero 2w to a pca9685 so I can control three servos on a robot. The pca9685 uses busses 0 and 1 according to the documentation. But the only overlays that are configured are i2c-3 and ic2-7.

when I try to connect to those two busses I get the following error: sysfs-i2c: no such device or address. When I try buss 0, or 1 I get this error: i2creg: can’t open unknown bus: “0”.

how do I go about putting an overlay on the radxa zero that defines busses 0 and/or 1.

the OS is armbian v25.2.3 with linux kernel 6.12.17-current-messon64

a little help would be great!

These 2 issues need to be clearly described:

  1. are you using Radxa Zero 2 Pro or Radxa Zero 3W ?
  2. pca9685 doesn’t specify i2c0 and i2c1, does it? Or you can post a link to the documentation you are looking at.

The Radxa board is a zero 2w. I did notice on the board it says radxa V1.51.
I think I was mistaken when I said the pca9685 busses were 0 and 1. I can’t find a reference to that in the docs.

Below is a screenshot of the armbian-config tool:

armbian-config-image

You can check which i2c device is in the /dev/ directory, then use armbian-config to turn on the other i2c overlay and reboot to see if there are more i2c devices in the /dev/ directory, if there are, connect to the corresponding hardware, and then use i2cdetect to scan the corresponding i2c bus to see if the device is mounted. on the corresponding i2c bus.

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