220VAC zero detection and other connections

Hi..
according to the notes in AVR document, lets say i connect the mains to my uC.
My test setup: Laptop usb powering my uC and UART connection using serial-to-usb connection to another port on my laptop to uC for debugging.

So should i remove all other connections before connecting the mains or is it ok for test purpose if i am careful.

On safety grounds I would advise the use of an isolating transformer to derive the mains input signal.

alec_t said:

On safety grounds I would advise the use of an isolating transformer to derive the mains input signal.

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My final design will not have any isolation, so i want to run from mains and see the output in my terminal program.
SO i guess i am good to go. i have to be super careful

something about connecting a micro to the mains makes me very uncomfortable! i think i am more surprised by the fact that microchip and others show how to connect there chips to the mains. LG has asked me a few times if he can try it and i might let him one day when i have the time to be there throughout! also it will have to wait until i have some kind of isolation in place.
i would find it very difficult to explain to the wife that the funny smell coming from the lab was infact her son slightly overcooked!

I did not get the guts to connect the mains while its all hooked up with my laptop... so i used a 220vac-12vac transformer to do the testing. I can effort to loose some uC but not my laptop.