LIS2HH12 - SDO Signal Distorted

[roger99]

Hello -
I have an Accel 28 board made by Mikroe that has the LIS2HH12 device. As per the Mikroe data sheet I set J1,J2,J3 to positions 2-3. I have removed J5 so that line isn't pulled up.

I've got the first 6 pins on the lower left up connected to my NUCLEO-L476RG development board.
GND, 3V3, SDI, SDO, CLK and CS. I have confirmed CS, CLK and SDI have normal and good signals. Yet, SDO is distorted, almost non-existent, but does return the correct value occasionally. Please see scope pix attached. Top is SDI/MOSI, bottom is SDO/MISO. I've also tried unplugging SDO pin from Accel 28 to STM32 to confirm it's not a loading issue. On this test the function did return the correct value of 0x41 to "Who am I" (0xF) command.
It's clear to see this is a peculiar signal and not normal at all. Also attached is Accel 28 schematic.

Could you please offer any suggestion as to what the problem might be? Have you seen this before?

Thanks!

[TDK]

Looks like both devices are trying to drive the purple trace. This is almost certainly a hardware connection problem, not a software setup one.

Recheck your pinout, verify pins are connected correctly. Ensure the pins you're using on the nucleo board are free and not used by other devices on that board. Post more details about your setup, mainly which pins are connected to what else.