> ok, if it's that easy I might be talked into doing it.  Would I do
> 16f628 or 16f628A?  Not sure what the difference is between those
> with/without the A.. just an update of some sort?

The differences that I have noticed are:
1) there are programmers (like the El Cheapo) that can program the
16F628, but not the 16F628A/16F648A, even with modern software.
2) Some revisions of the 16F628A/16F648A suffer from a bug that
requires you to basically halt your program while writing to the
EEPROM memory. This is rarely an issue, as most of the time you'll be
waiting for it to finish anyway.
3) The 16F628A is cheaper and can be interchanged for the 16F648A with
very little effort (the 16F648A is about the same price as the 16F628,
and therefore a good deal, unless your design states you don't need
the additional 2KWord).
4) Some mode bits have changed (ER -> RC, BOD -> BOR, PWRT can be
controlled separately, INTRC is called INTOSC, only one CP bit).
5) The Timer1 oscillator has been limited to 32.768 kHz, instead of
anything up to 200 kHz.
6) The dual speed oscillator no longer works in ER mode.
7) The 16F628A/16F648A consumes a lot less power.
8) All versions of the 16F628A/16F648A can handle 20 MHz. With the
16F628 there are different versions for different frequencies.

Greetings,
Maarten Hofman.

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