ZX Spectrum Keyboard Visualized

November 27th, 2012

Ok, I got interested in the keyboard membrane issue: which wires are actually the columns and which are the rows? If a row or column of keys doesn’t work, which wire is to blame? To help the debugging process I made a quick visualization (hey, don’t be too harsh on the aesthetics, I only teach at a design school) showing the traces and the corresponding keys.

Membrane visualization

Some curious things popped up immediately. First of all, the columns are symmetric: the leftmost column continues to the right end and so on. Another interesting finding was that the rows are not in a very logical order if you consider the wires going to the motherboard. The first three are nicely mapped but then there’s a sudden jump to the first row of the right side. The maximum amount of combinations possible with 5 by 8 traces is 40, which is exactly the number of keys on the keyboard.

edit: The Service Manual matrix image explains the workings nicely from another perspective.

Filed under: laitteet,retro,visuaalit

Kommentin kirjoitus

(pakollinen)

(pakollinen, ei näytetä)

(pakollinen)

XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

RSS feed for comments on this post.