Mike wrote:

> - incidentally, the unit uses the 68HC11 as it was the lowest cost one
> around that allowed external 32K EPROM, 32K SRAM and has 512 bytes of
> EEPROM on the CPU along with lots of A to D and reasonable speed etc...
> (Couldn't find a PIC big enough and at that stage it wasn't my
> decision either as to which CPU we ended up with).

  Wise choice.  Horses for courses.  68HC11s are used in most of the
more
sophisticated bar code and/ or "keyboard wedge" appliances I have here,
using significant amounts of code space and/ or RAM.  Why use PICs?
Only because they may be more AVAILABLE(!) and/ or cheaper than the
68HC11 and MAY execute faster.  However, using the serial EEPROM or RAM
devices loses all such speed advantage.

  Cheers,
        Paul B.