and3rson wrote:
So I spent a ridiculous amount of time trying to route the PCB manually, and I eventually gave up and used DipTrace to auto-route things for me
It's not bad! And I've created a monochrome version of the image.
Attachment:
v07_routed .png [ 655.08 KiB | Viewed 108405 times ]
I notice the headers attaching to VIA Port A and Port B are only 10 pins each. I'd suggest 14 or even 16 pins each so you can connect a ribbon cable to an external device and supply the device with power, ground and perhaps even an extra signal or two.
I guess you're anxious to proceed. But if you decide to do another pass on the design, you could save some space by using a smaller oscillator, if available. Alternatively, the oscillator could be relocated. Right now the width of the board (from west to east) is consumed by...
- oscillator, CPU, RAM, ROM, VIA. Instead, you could try...
- ROM, RAM, CPU, VIA
The ROM (in its ZIF socket) is comparatively bulky, which is one reason I think it might do well at the edge of the board. Half of that extra width can hang over the edge! Oh, and I was thinking the CPU would be oriented with pin 1 toward the north, whereas the RAM, ROM and VIA would have pin 1 toward the south. This will tend to untangle some of the bus lines, but maybe with the auto-router you won't worry about that. Still, it'd be interesting to see what it would produce if you start by arranging the chips as I suggest.
Whether you do or don't reorient the chips, I would still consider moving the oscillator. With the extra width that's freed up, maybe those two headers for Port A and Port B could snuggle up broadside right next to the VIA instead of being pushed off the end. Just an idea... Good luck with the project, and have fun!
ps- and as Garth says, you needn't bother with the pour -- it is not a ground plane.
-- Jeff
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