We're developing on a custom NRF53 board. With the I2C bus disconnected from all peripherals, but with external 10k pullups connected, we get the following waveform when attempring a transaction at 400kHz (yellow SCL, blue SDA):
It shows the device attempting to communicate (with its system voltage at 3.3V) and seems normal. If we remove the external pullups, however, then we get this:
As far as we can tell on the software side, the internal pullups are enabled, so its not clear why the waveform would be significantly different (and have strange timing)
