Trevor Switkowski

AC line zero detection with MCF5213

Discussion created by Trevor Switkowski on Aug 3, 2006
Latest reply on Aug 4, 2006 by Mark Hotchkiss
Hi everyone,

I was wondering if it is possible to use an a/d channel of the mcf5213 as a zero detect circuit for the AC power line. I have seen a schematic for an 8-bit controller using an input port for this purpose, but i don't see how it would be good to expose the i/o line to such high voltage? they used a 1meg resistor from AC+ to the uC pin, and a 1meg resistor from AC- to ground. will this be okay on the MCF5213, and will it give accurate results? I am also using a single supply of +3.3v for my uC system

Thanks in advance for any help!