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Comment by ChuckMcM | Hacker News Reader

Ok, wow. That is pretty stunning. That is months of painstaking layout and research. I am in absolute awe.

Windell and I talked about building a discrete 7400 (quad NAND gate), in theory you can build any logic you want out of enough NAND gates :-) but implementing the CPU on the PDP 8 was going to be a very , very big arrangement. at 13 in on a side this is pretty manageable. A lot of boards for the MicroVAX are larger than that.

Now the question is if you make a proportionally sized 40 pin package for it, how big is the Apple II motherboard? :-)

Nicely done, congrats on an awesome project. I must go to Makerfaire now to see this in person.

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He addresses the apple ][ idea. Since his board will be limited to 100s of khz (a PCB has signalling issues that an IC doesn't that will limit the max clock rate) and the apple ][ had HW with dependencies on the CPU being at a certain rate, it will not work just to build an adapter.

ChuckMcM doesn't propose hooking it up to an Apple ][ motherboard, he suggests building a replica motherboard at the same scale. At about 75:1 scale (6502 was about 4mm), that motherboard would be over twenty meters wide.

I'm in. Just need to set our watches back, right?

"the apple ][ had HW with dependencies on the CPU being at a certain rate"

On the other hand something like a KIM-1 would be totally doable although there would have to be changes to the cassette interface and TTY interface software timing loops. Oh and I suppose if you clocked below 10 KHz or something then keypad debounce routines might need some work. But from memory there would be no hardware changes necessary to downclock a KIM-1. There is a hardware PLL in the cassette interface input but all it does is sniff if the incoming tone is above or below some frequency

A KIM-1 was a rather simple 6502 single board computer from the dawn of the microcomputer era.

I also want to check this out in person. What day are you demoing it? Is there a booth, table, etc.?

My experience presenting at maker faire is that you don't know where your booth is going to be until you show up on Friday morning. What would help is to know what section it's in and what the name of the booth will be.

this is correct. it'll probably be in the expo hall. the exhibit is called "Making Dis-Integrated Circuits", see http://makerfaire.com/maker/entry/55149/

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