AVR-Chat

At 06:21 AM 24/08/2012, you wrote:
>So what happens if there is no Vcc, i.e., there is no supply power 
>applied to the AVR,
>but at the same time there happens to be Vcc on, say, a digital 
>input pin or a UART RX line?

The chip will try and draw power from that line. It's VCC (and the 
boards' VCC) will be the
voltage present at the pin less 0.5V.

So it is never a good idea to have power on pins of a chip which is off.

Regards

John Samperi

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