I'm working on a project that requires the use of an Atmel AT89C51 but I've never used any kind of micro before. For an idea of how much I know, I just spent about two days trying to figure out why mine wouldn't work when I discovered I needed to use a separate oscillator.

Question number one: my AT89C51 is of the 24MHz variety... does this mean I can use a 24MHz oscillator? I've been using a 100kHz input from a function generator, and it seems to be working fine.

Number two: At the moment I'm working on serial communication. If I want to program for a certain baud rate, does this require the use of P3.4 and/or P3.5? If so, how do I connect them?

Number three: I've noticed that the first time I apply power right after re-programing the micro, it appears to start up in Idle Mode, requiring a hardware reset. Is there a way to avoid this, or is it something I have to live with?

Thanks in advance!