I'd like to ask about how the SAG pin of ADE7753 could be used as a power supply monitor. On the datasheet, I've read that it would go logic low whenever ADE7753 goes into an inactive state and the analog supply (AVDD) is less than 4V +/-5%. I wanted to save the energy reading on an EEPROM when a brownout occurs. Temporarily, I programmed the MCU to save data on a regular basis since I still have to figure out how I could make use of the SAG pin as an external interrupt to the MCU. I placed a zero on the DISSAG bit of ADE7753's MODE register and I monitored the state of the SAG pin using an oscilloscope. I found out that it stays low all the time even if the analog supply is 5 V and the ADE7753 is operating normally. What else should I do to make the SAG pin work?
Also, I observed that the ADE7753 chip heats up a lot whenever I remove the analog inputs to channel 2 (220 V line) while the 5 V power supply is still active. Is this normal? Will it eventually burn the chip? I am a bit worried because I’m planning to place a large capacitor across the 5 V supply to hold it for a second or two during a brownout. This is to ensure that my MCU has enough time to save its last energy reading before it runs out of power supply.
Thanks a lot for all the help.