Raspberry Pi Forums

How does dtoverlay support for sensors handle i2c address duplicates? I say duplicates because I have a scenario where Pi A may have a SI7020 sensors and Pi B may have a HTU21D sensor. Both of these sensors use the same i2c address, which is 0x40.

I would like to have one consistent config.txt file, across all Pi devices if possible. So the dtoverlay configuration as follows is the desired result such that on Pi A and Pi B...
But I suspect what I have to do is...
Pi A... Pi B... It would be nice if the dtoverlay logic was smart enough to only use the actual entry that is applicable, I hope this is actually the case.

Use a serial number filter for config.txt.

Schorschi wrote: ↑

Fri Aug 07, 2020 3:56 am

It would be nice if the dtoverlay logic was smart enough to only use the actual entry that is applicable, I hope this is actually the case.

That isn't possible as there is no standardised autodetection mechanism for I2C. The only way you can identify something at a specific address is to read the registers and cross reference it against the datasheets. The Pi firmware isn't going to do that.