Alan B. Pearce wrote:

>>Anyway, we experimented with different matrix sizes and discovered that a
>>5x7 matrix seemed
>>to fit all letters (upper case only) pretty well so that's what we used.
>>
> 
> It also allows you to do a reasonable representation of most lower case, and
> sort of allows descenders on g, j, p, q and y, enough to make them
> discernable for what they should be.
> 
> To get properly decent looking characters you need a 9x7 matrix for proper
> descenders, and Motorola used to make a very nice ROM which had a 9x7 matrix
> mapped into a 9x16 space, giving excellent descenders, without requiring the
> full 9x16 space in the rom, it required a 9x7 plus 1 bit per char to signify
> it was shifted for the descender.
> 
Came in on this one late. The following article


http://www.swtpc.com/mholley/RadioElectronics/TV_Typewriter.htm

was one of several Don Lancaster did in the early '70s when I was
in High School. Got me interested (more interested) in electronics.

Jim



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