a long time ago (must be about 10 years now)... I was involved in a similar project, but it was only a number of 7-segment displays. It had to be cheap and scaleable. My idea at that time was to use an 8bit latch (standard 74xxx) for each display (in your case each row or column). The input of these latches was wired in a parallel 8bit bus and a binary-decimal decoder provided the address selection for blocks of 16 displays to latch the bus data into the chips. The control was done through a standard parallel printer port using the control lines as address lines for the display.
Uwe. Declan Moriarty wrote: > > I have a need to switch a 64 way exhibition piece in an 8 x 8 matrix. We are > farting about here to impress. The output stage I can manage. It's the > control strategy I am wondering about. Due to design considerations I cannot > multiplex outputs, so driving with 16 switches (8 columns and 8 rows) isn't > practical . > > It has to be controllable by a demonstrator, and they're not printing > characters or any standard shape; what is wanted is an efficient and humanly > usable interface to address these. I looked at remote control ics, but the > interface is too well integrated into a tv. Ditto serial connections. I > haven't multiplied out the combinations, but it is daunting(zillions). There > will be a pic(16f877) based pcb I can attack and alter if needs be, but my > coding skills are primitive. Mind you, the pic16f877 isn't. > > The very basic would be addressing the cells individually via a pc & serial > port. Anyone got a better plan? > -- Author: Uwe Zimmermann INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
