Can you check if the ADE7953's reference pin voltage( pin 13) is close to 1.2V? Also check if VINTD and VINTA pins are at 2.5V,as expected. By default, ZX pin (pin 1) will act as a zero-crossing indicator for voltage channel input. So, apply a full scale voltage signal to the chip and observe the ZX pin output on scope. If you get a proper ZX indicator too, then it means that the chip is fully functional. If you still get no response from the chip in UART mode, then:
1. Try double-checking the Tx/Rx pin description in MCU as well. It is a common error to swap the connections.
2. Do you have ADE7953 evaluation board. If so, try connecting an external MCU with the ADE7953 chip on the evaluation board? Does UART communication work now?
Also, as discussed, whenever possible, kindly provide me the oscilloscope images of UART frames transmitted.
Regards
hmani