[Coco] Re: [Color Computer] Re: MC-10 joystick interface

[Torsten Dittel]

Thanks for figuring this out. I'll post a schematic and a layout after
completing my testing of Roy's CoCo2VGA converter which had been delayed
by the preparations of my weding party last saturday.

Torsten


> The chips closest to the connector are 74LS138N's.
> That's a 1 of 8 decoder/demultiplexer.
> http://ece-www.colorado.edu/~mcclurel/sn74ls138rev5.pdf
> Those do the address decoding.
> 
> The HEF40097BF is a "3-state hex non-inverting buffer".
> http://www.datasheetcatalog.com/datasheets_pdf/H/E/F/4/HEF40097BF.shtml
> This provides the connection between the joystick and the data buss.
> 
> The decoder sends out an enable for the buffer to output the lines
> passed through the joystick when it's address is accessed.
> 
> The caps are for noise reduction and the resistors probably keep the
> inputs to the HEF chip low till the joystick is moved or a butten is
> pressed and then those lines on the HEF go high.
> 
> It should be easy to reproduce.