As you may remember, I’ve designed a universal platform for building retro-computers “Retrobyte”. I have successfully tested it by building the “Mikro-80” computer a few months ago and now I’m working on adapting my other retro-computer project “AGAT-7” to this platform.
“AGAT-7” requires more functionality than “Retrobyte” has, so I’ve build an extension board for it which has sockets for a 6502 CPU, original keyboard and joysticks, and an extension slot for an original “Agat” extension card (e.g. serial-parallel interface card). It also has a socket to connect a floppy drive or its emulator on SD cards (e.g. HxC).
Here is the schematic of the board:
And here is its photo:
It has the same size as the “Retrobyte” board (10 x 10 cm). This is how they look together assembled:
Compared to my initial “AGAT-7” project, it will have some additional features:
- Exact simulation of all timings of the original computer, including interrupts. It will help to display screens with combined graphics modes correctly.
- VGA output will be built via frame-buffer to preserve original timings. SDRAM controller has to be modified too to accommodate it.
- The addition of an “AGAT-9” computer replica to the same platform to make a 2-in-1 computer with the ability to switch between them.
I’m going to use Twitter to provide further updates of the project, so please follow me there if you are interested in its progress: