I want to establish a SPI communication between my Raspberry Pi Zero (Master) and the Energy meter ADE 7753 (Slave). For that i need an SPI isolator, in my case it is a ADUM3153 with 3.3V on primary side and 5V on the secondary side(isolated). When I measure the SPI signals on the primary side, without the ADE 7753 connected (just RPi and SPI Isolator), I am getting the following:
I am wondering how is it possible that I am seeing the delayed MOSI signal on the MISO line? Is there any explanation for that?
For me it looks like as if the MOSI and MISO are coupling internally. I also checked the connections for shorts.