To determine whether there is an open circuit (high impedance) or short circuit (low impedance) between two terminals, you apply current and measure the voltage across the terminals, or you apply voltage and measure the current.
You need to do this with or without a pic micro. The measurement of the voltage and/or current is done using analog circuits with the output either an analog value that you put into the A/D input on the PIC, or a digital voltage (0 or 1) from a comparator that you put into a digital input on the pic.
Thank you Mr.Marke for your advise! Thank you very much.
You helped me more knowledge.
The reason I want to use microcontroller is I think it's like pro... I think so? Is it right?
Use PIC, I can practice and improve my skill. I want to check open and short circuit a same time also.
Pls give me more advise about PIC, about digital voltage with comparator... if you have free time.