Well Jay,
That's why I posted here to get knowlegable people's help, like yours. 27
years experience I can't pick up from a couple of books!!
Thanks for the info but I'd rather have a simple circuit than to have to
read books on both electronics and micrcontrollers.
But, well thanks for the info but a circuit would have been better? That's
what I asked for!

"happyhobit" wrote in message
...
Well Ian,

The AT89C4051 is a 3Volt, 80C31 Microcontroller with 4K bytes Flash,
20-Pin
Package. XTAL-1 and XTAL-2 is where the 24 MHz crystal, that clocks the
microcontrolled, would be connected. You could also use an external clock
signal and feed it into XTAL-1 to Ground.

Check out the Atmel website. http://www.atmel.com/

And for the AT89C4051;


http://www.atmel.com/dyn/products/pr...04&family_name
=8051+Architecture&part_id=1939

The 'Location Counter' you mention is probably the Program Counter. This
keeps track of the instructions the microcontroller is executing.

Pins 4 and 5 are XTAL-1 and XTAL-2.



If your not familiar with microcomputers / microcontrollers you probably
need to pick up a couple of books and start reading.



I did, 27 years ago. : )



Jay