driving two-digit displays...

OKST8

Hi all...

I'm new to the whole BASIC Stamp arena and I have some questions.

I'm trying to set up and control four two-digit displays each with separate keypads.· I had intended to use·four "Ser-Key" keypad encoders from Rentron so that I could customize the layout of the keypads and only have to use one i/o pin per keypad.

Here's where I need some advice.· The displays aren't the traditional seven-segment type.·· They are the eight-segment type that are used on older incandescent scoreboards.

Any help on the following would be greatly appreciated and I will gladly·post the resulting schematics once I get it working.

First...Can I get away with using only one BASIC Stamp to do this?· If so, any recommendations on which version?

Second...Does anyone have any programming suggestions or examples on·latching for the two digits?

Also...Any programming or hardware suggestions·on converting the data input·from the SerKey into data output·that can specify the correct combination of lighted segments.

I know this is a vague description so if you need any clarification just ask me.

Thanks in advance for your help...

Rod




·

OKST8

Another thought...

How effective would the MAX7219 8-digit driver be for this application?· Since it's configurable to drive 64 separate LEDs, could it also be used to drive the same amount of relays to run the displays?

Thanks,

Rod

Jon Williams

The MAX7219 is a multiplexer, so it's not appropriate for driving mechanical devices like relays. If you need to drive a bunch of relays you can daisy-chain 74HC595 shift-registers.

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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA

OKST8

Jon,

Thanks for the direction.· That's exactly what I was looking for.· I could just use two of those for each display.

Can anyone point the way to some sample programming that I could make alterations to?· I think I need three examples to get this going.

1. An example of BASIC programming that will create the final·data output for the shift-registers.· Maybe a modification of some already existing·7/8 segment·LED programming?

2. An example of how to store the data from the first keystroke and then combining the two.

As you can see, I'm totally starting from scratch on this from a knowledge and electronics standpoint.· I have some BASIC programming knowledge from High School in the mid 80's, but that's been 20 years ago, so any jumpstart I can get is appreciated.

Thanks again...