* On Tue, Feb 28, 2017 at 09:55:30AM -0600, Jim Brain via cctalk <[email protected]> wrote: > Analog, which is my nemesis, curses me again. > > I have a cute idea for a cassette port project for the Tandy line of > computers (the ones with the cassette port). I have a Coco 3 on the bench, > so I scoped the output line while doing 'csave "jim"'. The signal looks to > be just under 1V PtP (0-1V on the scope), and rests at about .3V when not > sending data. > > I have tried 6 different ways to boost the signal to 5V digital, to no > avail, and so I ask humbly if someone with analog knowledge might be able to > assist.
Hi Jim, When I was building a cassette circuit for my homebrew 6502 computer, I essentially stole the Synertek SYM-1 circuit wholesale. See: http://www.loomcom.com/blog/2013/01/04/retrochallenge-update-comparator-vs-zero-crossing-detector/ http://www.loomcom.com/blog/2013/01/05/comparator-success/ Synertek used an LM311 (an LM358 would work just fine) to build a comparator circuit. I _think_ you could use this exact circuit to take the analog output from the CoCo and turn it into a 5V sqauare wave. -Seth
