My first board seems to work really well (other than the JTAG being reversed!).

So I thought I would revise the board and fix some of the mistakes. Also, I decided to go SMD for most of the parts so that I can get the caps on the back side and closer to the pins.

I don't have the silk screen finished yet (I will label each I/O pin, etc.). But this is what I'm going with so far.

Also, I decided to put an oscillator onboard to drive any of the GCLK pins which can be selected with a jumper.

Suggestions welcomed!

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Cat; the other white meat.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

A reset supervisor and/or a reset button is nice to have.
Bill

Thanks, BDD for the tip. I think I will stick with CUPL solution since most of the board is done.

@Plasmo,

I thought about a reset button but I'm not sure how that would work. From what I understand, the GCLR isn't really a reset is it? Meaning, simply taking it to GND doesn't do a full reset or am I wrong?

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Cat; the other white meat.

GCLR is a general purpose input, but generally used as a global reset input. If you have buried flip flops, they do need to be reset to known values so GCLR is used for that purpose.
Bill

Right, but you need some "logic" to make this work, IIRC. It's not like a /RES on a CPU or something like that where everything gets cleared.

Hmm. Shoot. I might put one in there anyway.

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Cat; the other white meat.

I don’t know how CUPL handles it. In schematic, I bring in an input signal assigned to the GCLR pin, let’s name it nRST; then I connect nRST to the reset terminal of flip flops that need to be cleared; or I connect nRST to preset terminal of FF that need to be set; or I can use nRST as signal to drive logic.
Bill

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Push button added along with DS1813 (U3).

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Cat; the other white meat.

PCB's ordered for Rev 2!

I added a couple ground test points and decided to go with purple. Love me some purple.

JLCPCB:
$8 for the boards, $12.80 to ship and $0.50 PayPal fee. Grand total: $21.30
Shipping: 2-4 days DHL!
Layers: 4
Size: 74mm x 69mm


PCBWay wanted around $96 for the exact same thing. Not sure why people keep using them other than the tons of sponsorships they do on YouTube channels which means they get tons of recommendations. Nothing against them, just way too expensive.

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Cat; the other white meat.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Who knows if I will like the purple or not. Purple is actually my favorite color so I guess I'm biased. OSH Park started that whole purple thing but my goodness they are pricey.

I've done boards in green, black, red and blue. All look good to me so hopefully the purple will too.

I still need to do white and yellow. I have a white board from someone else (Propeller C3) and it looks good but I'm just not a fan of white boards. Yellow will take some convincing but I may do one just to give it a chance to grow on me. But that is doubtful.

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Cat; the other white meat.

Some of my favorite childhood memories are playing around with some old DEC and IBM boards that my dad's friend gave me. They were a vaguely olive color and had beautiful hand-routed traces.

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Got a kilobyte lying fallow in your 65xx's memory map? Sprinkle some VTL02C on it and see how it grows on you!

Mike B. (about me) (learning how to github)

Yeah, that is a beautiful board. Hard to beat green when it comes to nostalgia too.

That shade of green has changed a bit too. Everything from olive to bright green.

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Cat; the other white meat.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!