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+--- Thread: CM3 i2c configuration (/showthread.php?tid=5336)
CM3 i2c configuration - spacel0rd - 05-14-2022
Hi all,
Posting to describe an i2c config issue I found while setting up my CM3 kit. I resolved it; just leaving a note that may help someone else. I have the CM3 board v1.5 with a non-plus compute module, no add-on boards installed.
I've already had many hours of enjoyment with this kit; thanks to the Freeplay team for making a cool product. Also congrats on launching the new Zero 2 hardware version!
I found i2c did not work on my build (integrated brightness controller wasn't recognized), but only with the newer SD images (dated after 12-May-20). The 'Freeplay_CM3_20051201' image worked as expected. The fix was to apply a different device tree overlay. Working from the 21110201 SD image, I replaced the default:
'dtoverlay=i2c1-bcm2708,sda1_pin=44,scl1_pin=45,pin_func=6,combine=off'
with:
'dtoverlay=i2c1,pins_44_45=1,combine=off'
baudrate was set to 400000. i2cdetect then returned all the expected addresses, and brightness control worked.
I couldn't find an exact reason why this change was necessary, other than dtoverlay help text stating that 'i2c-bcm2708' is deprecated. Help is accessed by 'sudo dtoverlay -h <overlay>'.
Has anyone else encountered this?
RE: CM3 i2c configuration - Flavor - 06-15-2022
I'm sorry that I didn't reply before.
This is good/correct info. They must have removed i2c1-bcm2708 at some point.