STPM3x Not Reading in Correct Measurements

[radarcontact]

I am working on a project with the STPM3x chip. We have a custom PCBA that does not appear to be working. I am able to communicate with the chip via SPI. I can set the gain registers and read them back. However, the voltage and current measurements are not correct/existent. I can read them in but they make no sense. Doesn't matter if I have power applied to the chip or not they come back erroneous. We copied the board design from the evaluation board. The code works with the evaluation board so I'm confident the firmware is correct. I did notice on pin 27, we connect to VCC (3.3V) and it looks like on the evaluation board that shouldn't be but I can't imagine that is causing poor measurements. Curious if I could get an FAE at ST look over the design and see if they seen something I don't. 

We are using a different crystal than the eval board but I imagine if I can read/write registers than the crystal is not the issue. I imagine the crystal is used to generate a clock for the digital section of the chip. 

I will also point out when trying to reach the measurements everything seems erroneous not even uncalibrated. 

Happy to send PCB layout, schematics, or whatever else you may need to help us out. Thank you in advanced. 

[Peter BENSCH]

I had previously overlooked your question because you had categorised it incorrectly. Do you still have the problem?

You mentioned the EVALSTPM34 in a later thread. Is it the board from which you derived your board?

By the way, pin 27 is VDDD, which is NOT identical to VCC, but an output of a 1.2V regulator. In the worst case, the STPM3x was destroyed by this, but you can check this by disconnecting the connection from pin 27 to 3.3V.

Regards
/Peter