hbc-56 VS 6502

I use a PIC16F microcontroller. Schematics and PIC code in my HBC-56 repo. https://github.com/visrealm/hbc-56

If you're keen to add a VDP as u/production-dave suggested, I have schematics and a bunch of code in my HBC-56 GitHub repo

Schematics are here https://github.com/visrealm/hbc-56/tree/master/schematics/6502

The schematics for my TMS9918A display card are in my github repo. It uses a single SRAM instead of the original DRAMs. The circuitry between the TMS9918A and the TV is just a simple transistor follower circuit (shown in the schematic): https://github.com/visrealm/hbc-56/tree/master/schematics/tms9918

So this is really just cobbled together from this project by u/visrealm https://github.com/visrealm/hbc-56

I've actually just ordered the perix perrino 409 that sends the AA after self test. The HP keyboard definitely doesn't seem to be working. My plan is to interface it with a PIC microcontroller by copying the setup here: https://github.com/visrealm/hbc-56. from u/visrealm

It looks like a shift register can be used in connecting a NES controller but likely isn't the full story. Check out u/visrealm's HBC build. He uses separate shift register chip to connect to a NES but maybe the 6522 can be used in a similar way.

It's Assembly. https://github.com/visrealm/hbc-56/tree/master/code/6502/mandlebrot

I have most schematics, software, emulator, etc on github. https://github.com/visrealm/hbc-56

These are for a 6502 build. https://github.com/visrealm/hbc-56

The Apple 1 ROM is quite a tight piece of coding. Just 256 bytes which implements basic console IO, and memory editing in hex. And still two bytes left over.

One version with lots of comments: https://github.com/jefftranter/6502/blob/master/asm/wozmon/w...

You can see a classic assembly language space optimizing trick at PRBYTE. It first prints the upper half of the byte in hex with call to the PRHEX procedure, then falls through to PRHEX again to print the second half. Two entry points to a common routine.

The First Book of KIM programs

For a command line program I started out with getting WOZMON working and then began adding more capabilities similar to the Apple II system of old. I got tired of adding one-off functionality and discovered Forth when looking at programming languages suited for systems with limited resources. Look into TaliForth2 to get up and running fast on your 6502. The full program requires 24k ROM but can be slimmed down to fit in 16k pretty easily. I was inspired so I wrote my own Forth 2012 Standard version over the summer.

Jeff Tranter has a github with a ton of stuff 6502, including a mini assembler. Many others out there as well.