Schematic verification

Hi everyone, and thank you in advance for your advice.

I was able to test the EVAL-AD5522 test board with an ESP32 and MicroPython code I developed. It worked correctly.

Then I developed a board with an AD5522JSVUZ and an STM32H7, but it wouldn't work. I have nothing on the AD5522 outputs. So I pulled some wires from the SPI communication to reconnect the ESP32 and test the code that worked on the EVAL-AD5522 board. The only difference is the /LOAD pin, which I permanently set to GND.

I still have nothing on the AD5522 output of my board.

Here are the tests I performed:

- I have SPI communication from my card and I was able to compare it with the AD5522JSVUZ card = OK (I checked that the CS goes to 0 before the frame and that the frame sampling is done on the falling edge)

- When I set a REST (1-0-1), the BUSY pin changes and stays at 1

- When I send a message, the BUSY pin never changes = this is not normal

On my schematic:

IC1 => IO0 to IO3 are output and at 0, IO4 cycles 1-0-1 at startup, IO5 is an input

All SBs are connected and the power supplies are checked.

I'm sending the following message at startup:

0x003FE4A0
0x0F21B300

Then, I want to force a voltage of 4 volts on all outputs and measure a current of up to 2 mA.

0xF219300
0xfcdad83

I was able to verify the messages with the software from the EVAL-AD5522 board.

Is there an error in the schematic that's causing this not to work? Are the frames I'm sending the wrong ones (they're the same frames with the ESP32 that worked on the test board)?

What other tests can I do to verify the operation of the AD5522 on my board?

PDF

Thank you again for your support.