A very simple computer.
Address bus latch.
A one-of-seven selector.
Simple 8-bit "bus".


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You can also use your local clone with git send-email.

#A Very Simple Computer

This repo covers the simple prototype computer I'm building, notes, schematics, code, etc.

Wed Dec 14 08:46:43 PST 2022 Something went wrong last night. I set up the system with three AVRs in a daisychain with the RPi and started the test script sending bytes to the SPI system. It was working fine, the pattern comes out on the LEDs (it looks cool.) So I left it on overnight (I forgot to turn it off and fell asleep watching TV on the couch with the dog.)

This morning the pattern was frozen, and the SSH session between bock and the RPi was too. When I rebooted the Pi it didn't get the right IP from the router. When I tried logging into the router through the web interface it wouldn't connect. I restarted the router. If it's flakey, due to DD-WRT or whatever, it's out. Life is too short for flakey hardware.

I also plugged bock back into the main subnet (from the cable company router) and it picked up the new IP right away but then couldn't reach the Internet! I rebooted the router just to do something, and now I can read HN, etc.


The real WTF is that I would be so fucked if I had to diagnose and fix anything harder than "reboot the router" right now. I feel like a shadow of my former self in re: technical knowedge and skill. I was never some hotshot y'know? But at least I stood a good chance. Here I have no idea what went wrong, no idea which part or parts of my system are faulty, and worst of all, no real clue how I would go about discovering that.

Fortunately, rebooting the routers and the RPi seems to have fixed everything (ha!)