I'm having slight problems with the CM3+ module...

I've written the dts overlay and got SCL1 and SDA1 working fine. The pins 28 and 29 should be SDA0 and SCL0 respectively, which is confirmed when I type raspi-gpio get 28,29.

So it should be set. But whenever I type i2cdetect 2, 2 because it's detected under /dev/i2c-2, it just goes slow, probably timing out on the pin detects. It goes much slower than i2cdetect 1.

I'll provide additional info if needed.

UPDATE: The BCM numbers for above GPIO numbers are:

GPIO-28 - B12
GPIO-29 - B1
  • Pin numbers on the compute modules are different to the other Pis. Could you quote Broadcom GPIO numbers which are common to all Pis.
    – joan
    Commented Jun 12, 2020 at 8:01
  • pins are 28 and 30. Above 29 becomes 30 and that's it. Commented Jun 12, 2020 at 8:03
  • I have already said pin numbers are meaningless. Could you edit your question and use Broadcom GPIO numbers?
    – joan
    Commented Jun 12, 2020 at 8:06
  • @joan I'm sorry, but I thought those were the ones, as they differ from the ones listed in the raspi-gpio where could I get those pin numbers? Commented Jun 12, 2020 at 8:18
  • 1
    @PMF yes, SDA0 and SCL0 are on pins 0 and 1, but they're also on 28 and 29, and we can't use pins 0 and 1, because we're using a DPI display on the bank0. I've also solved the issue by upgrading the kernel to 5.4.45 and it suddenly found i2c-0, i2c-1, i2c-2, i2c-10 and i2c-11, where 1, 11 and 2 are HW ones and 0 and 10 are "i2c-11-mux" Commented Jun 12, 2020 at 13:08


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