IBM 5150 in S100?

Dave McGuire mcguire at
Wed Mar 30 10:29:06 CDT 2011

On 3/30/11 2:06 AM, Rod Smallwood wrote:
>    I don’t know if this helps. I worked in VDU design and development in the
> mid 1970's. The keyboards used a system with a 74150 and I think a '154.
> These are a 16 line binary to decimal decode and an eight line to binary
> encoder.  The outputs of the one and the inputs of the other formed a matrix
> with the keys (switches) at the junctions. A counter drove the inputs of one
> and the selects of the other. As soon as you got an output the counter
> stopped and its value became the pressed key value.

   Fairly standard matrix scanner..


Dave McGuire
Port Charlotte, FL

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