Saturday, 9 August 2008


If you haven't happened across the Instructables website I'd highly recommend it. It is a website devoted to communicating how to do things.

A large variety of topics are covered, but I was especially interested in a couple of descriptions as I have been looking at the issues around creating a display out of seven-segment digits. I bought a whole load off ebay a while back and am looking at creating a display comprising 10 rows of 8 characters.

The maxim chip MAX6951 uses a technique called Charlieplexing. It trades complexity of the driving logic for number of connections. I'd come across the chip (and the technique) before without knowing how it came about. Anyway, if you're interested an explanation can be found on instructables here.

I haven't found an easy way of providing a display with so many characters. Multiplexing breaks down as a technique past about 8 characters, and this in turn means the chip count goes up.


Andy said...

I hadn't realised you were into the low-level hardware so much ;-)

Mark Wickens said...

Oh yes, well, a bit of a dabbler but I try my best. Must get that display put together at some point, that many seven segments running at once has got to be impressive...