Hi Areo
You are in the correct place to get technical support for the issue you are facing. I can definitely help you resolve this problem.
If isolation isn't a concern, use connector P11 to interface with the external MCU.
1. Do not power the MCU side of the evaluation board ( P12 should not be powered). This would ensure that the isolators and MCU remain switched off. You can open the JP2 jumper to limit the supply to isolator on the ADE7878-side (VDD2) and see if it helps.
2. The P11 connector looks like this:
3. Keep the PM0 pin high and PM1 pin low before powering-up the ADE7878 side of the evaluation board. This would ensure that the IC powers up in PSM0 mode. Once the IC is powered-up completely, you should see the IRQ1 pin go low signalling the RSTDONE status bit being set. How does the SPI pins look at this point, on a scope?
4. Toggle SSB/HSA pin three times to select SPI communication and lock the port by writing to the CONFIG2 register.
5. Read STATUS1 register and write it back with the same value. The IRQ1 line must go high again. If it doesn't, try verifying the SPI timing characteristics listed on page 13 of ADE7878 datasheet Rev.H. Do you follow all of them correctly? Can you provide the SPI scope plots when you are trying to read something from the ADE7878 IC?
Regards
hmani