[sdiy] Driving LEDs

[Glen]

At 12:40 PM 12/22/03 , Harry Bissell Jr wrote:

>How about shift registers and a cueue'd serial
>connection... you'd send out a clock and data
>from the pic on two pins.  You could clear the
>whole thing by writing out more zeros as data than the
>length of the register...

I was just about to suggest this myself. Older Rodgers organs were
controlled by a single-board-computer that communicated with hundreds of
LEDs, switches, keyers, mutes, etc.--scattered over dozens of different
circuit boards. 

This was done by simply connecting small, 4-conductor shielded cable from
the CPU board, to all the other boards. Just three signals--Serial Data,
Clock, and Strobe were all that the CPU needed to share with the other
circuit boards, to communicate with several hundred devices. Depending on
exactly what your design needs are, this could work great. It certainly
worked well in the Rodgers organs.

Just don't remind Harry that this resembles a bucket brigade.   :)


later,
Glen Berry