ESP32 / LED1202 - Weird SDC I2C waveform shape

[TAMHAN]

Hello Folks,
banging my head for quite some time (aka all night) over this issue and wanted to ask for some help.

I have a system where one to four LED1202 are driven by one common ESP32. On my PCB, sadly, the ESP32 cannot communicate with the LED1202, it always returns ESP_FAIL. On the oscilloscope, I see these waveforms attached.

Strangely, I also have an ES8388 attached to the same bus. He has no problems whatsoever with responding reliably.

Did anyone of you see these kinds of phallic shapes on SDA (chan one) before? And please do not worry about the ticks, they are caused by the LED lighting in the lab.

Tam

[Heartbreaker]

It looks like the ack. bits are messed up by a bus conflict. Check that the ESP32 tri-states the bus during this phase.

[TAMHAN]

Hello,
actually, it was even weirder. IBF Target miscalculated the ground plane, so the LED1202 did not have proper grounding.   

New spin, board works.

But still, big thanks for talking back!