Hi Guyzz
I have a M32 board that will get power from a 12v Accu connected to a charger , but i would like to signal when main power is down.
I have been looking at the Atmel App note for Zero crossing , and was wondering if that would be an easy way of detecting the 220v Mains.
I was thinking about running the 12v AC from the charger transformer through 2 resistors 47K , just as Atmel uses 2 resistors of 1M (220v).
Then i would detect on external int if there is 50hz , but id there a smarter way (i mean as cheap as 2 resistors , or just about as cheap).
/Bingo