Apple IIe
This one is a whole machine rather than a board I designed, so it sits a bit sideways in this notebook. There’s been very little refurb work on it. Most of the hours have gone into software: booting things, moving disk images over serial with ADTPro, and writing 6502 in Merlin on the machine itself. I cross-assemble on the Mac sometimes, but it’s more fun to write it in Merlin. The Byte Hamr card lives in this machine, and most of the hardware experimenting happened over on that project.
Current state
As of 2026-09-11: Machine works. Merlin is where the day-to-day 6502 gets written.
Architecture
How the pieces fit. Block diagram or a few paragraphs.
Hardware
- Apple IIe, 128K.
- A2DVI board for HDMI out. The same signal feeds a USB capture stick on the Mac, which is how the screenshots on these pages get taken.
- Serial card, with ADTPro on the Mac side for moving disk images back and forth.
- Byte Hamr FPGA card in a slot. That project page covers that side.
Gateware and firmware
Repos, toolchain, how to build.
Decisions
- Merlin on the machine for 6502 work. Cross-assembling on the Mac is for when I need the turnaround, and the results come over serial.
- Aztec C stays on its 800K image as a tools disk (grep, diff, hd, ved), but I’m not writing C for this machine after the 11.9K hello world (2026-09-11).
Open problems
Links
Software
Everything here is Merlin32 6502 unless it says otherwise. Sources live in the project_byte_hamr repo under software/.
Byte Hamr
Needs the card in the slot.
- FARM. Farm and market game. The //e draws a 20x20 plot grid in lo-res with a text HUD and takes input. The world lives in SDRAM bank 32 and is owned by FARMTASK, a skill running on the card’s soft 6502. WORKTASK in bank 33 handles the workshop and crafting.
software/SDM/FARM.S - MVERSE / GRVERSE. Conway multiverse. Eight universes get stepped by LIFE8 skills on the coprocessor, and the //e blits one of them to double hi-res at 560x192, or lo-res at 40x48 in the GR build.
software/SDM/MVERSE.S,GRVERSE.S - A8. One-program 8008 environment on the //e: 80-column editor with the ASM8 core built in. Ctrl-A assembles, Ctrl-G streams the object to the 8008 card and drops into its TTY. Shipped 2026-07-08.
software/B8008/A8.S - ASM8. Native Intel 8008 assembler. Reads a ProDOS text file, writes a BIN with the aux type set to the ORG. Shipped 2026-07-08.
software/B8008/ASM8.S - B8RUN, B8TERM, B8CMP, B8TEST. 8008 loader, glass TTY into the 8008 monitor, byte-compare for two files, and the card presence and FIFO self-test.
software/B8008/ - LOGIC. Front end for the Logic Hamr capture gateware. Arms a capture, waits on the trigger, draws 8 channels on hi-res with trigger modes and zoom.
software/LOGICHAMR/LOGIC.S - Self-tests. FARMTEST, CONWAYTEST, SDMTEST and the CP* loaders exercise the coprocessor scheduler, the SDRAM banks and the flash save and restore path. Bring-up tools, not things to run for fun.
software/SDM/
Standalone
- STARSHIP, PLANE. Small hi-res sprite and shape demos.
software/ASM/ - Aztec C 3.2b disk. The eight release floppies merged onto one 800K ProDOS image with a loader in front of the Manx shell. Kept as a tools disk. See the log.