MSP430F67791: 3phase sequence detection using software

I do not have software to do what you want.

But you have to have HW to isolate the high voltage power from you low voltage processor.

If you are metering you need to use a ADC. And sample the waveform enough to get the area under the sample.

If you are only interested in phase then protect the processor from the negative side of the AC and use logic pins to detect when the AC wave is greater than 0. with 3 logic pins you can determine the order of the phases.

That is the basics of how you do it. The details are left to the student.

Sir,
I have isolated HW. What is the procedure to findout the phase sequence detection.I have also getting the ADC value and also calculate the phase to phase voltage.But dont findout the phase sequence detection.My question is how to findout the phase sequence detection.Pls give me some logic details.As soon as possible....
Thanks,
Ashokkumar

It seems like if you are detecting phases then it should be a simple matter to check the order of when they hit the peak voltage. In a three phase system you should be reading three phases 120 degrees out of phase. One phase will peak, then a little later another phase will have a peak, and a little later the third will peak. That is the phase sequence.