[Coco] Kips 6809 SBC

[Gene Heskett]

On Friday 02 October 2015 13:12:02 Louis Ciotti wrote:

> I got enough parts in to have the following:
>
> Hitachi 6809P, 7.3728 Crystal, 2 x 15pF caps.
>
> I placed them on a small breadboard with one of the cheap breadboard
> PS from ebay.  Wired VSS, the crystal, and the caps.
>
> This is the E and Q Clock output:
>
> http://tinyurl.com/owko2q9
>
Teacher mode on.

Looks possibly ok, but to this old scope trace observer who has had a 
scope probe in one hand since 1951, your probe's ground lead is too 
long, so the scope if quite likely fibbing to you.

The ringing on the low logic probably isn't really there, but in your 
test setup.  I also suspect you had a ground clip with an 8" or so lead 
connected on the upper traces probe, but no grounding clip was connected 
on the second probe showing the lower, blue trace.

Don't give a scope a chance to lie to you, that ringing on the lower 
trace could occasionally be seen as noise on the other side of a ttl 
inverter.  Unless your breadboard layout is pretty sloppy, I'd have real 
serious doubts it really looks that bad.

> I also tied D2 and D5 high, and the Address likes are counting.  I
> need to move it to a larger board and find my stash of LEDs and get
> those hooked up, and I will attempt to make a video.
>
> I did not do anything with the reset line.

It seems that you are succeeding, please carry on.

Cheers, Gene Heskett
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