28 Feb
2017
28 Feb
'17
10:50 a.m.
On 2/28/2017 11:42 AM, Seth Morabito via cctalk wrote:
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-…
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.
I will give it a try. Obviously, I'll need to reset the bias down to
.5V from 2.5V in your design, but I can do that. I notice the design
has no feedback, but has R93 feeding the reference into the inverting
input. Any idea what the function of that resistor is?
Jim