[Coco] It's a small win, but a win nonetheless

RETRO Innovations go4retro at go4retro.com
Sat Mar 11 02:34:22 EST 2017


On 3/11/2017 1:22 AM, Dave Philipsen wrote:
> Well if you can make it work without the cap then fine.  I guess I 
> don't know exactly what you're trying to build but if you are always 
> going to hook it up to a known entity that always has the same 
> characteristics you'll probably be ok.
My goal is to read the data from the cassette port into an Atmel AVR 
MEGA168.
>
> So you're saying that the waveform you're getting from the CoCo swings 
> between .6 and 1.3v referenced from ground? 
Yes, but you are correct, I should try on a few machines.
> I guess I'd just want to be sure that that spec will always remain the 
> same without variations between different computers.
I was able to clean up the jitter in the signal with the decoupling in 
place, but the end result (even with a 10M resistor to ground to help 
with the jitter that was left, the swing in the signal went to almost 
nothing (.4Vptp).  I am worried that does not give me much for noise margin.

Jim


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