The ISA (Industry Standard Architecture) bus was a 16-bit bus based on Intel’s 80286 microprocessor introduced by IBM back in the early '80s. Believe it or not, it is still used in ATA/IDE, PCMCIA, Compact Flash, and in some Super I/O chips. ISA is a proprietary bus designed by IBM to automatically detect and setup computer peripherals, such as modems, sound cards, and video cards. While ISA may be a relic of the past and no longer supported by modern PC standards, that hasn’t stopped some hobbyists and retro gamers from using the communication system.
Tobias Madel is one of those looking to learn more about the ISA bus and to help him along the way; he’s created an ISA platform that allows him to interface a VGA in a VM (Virtual Machine) over USB. Madel designed his ISASTM (ISA-over-USB) adapter around an STM32H743 microcontroller and an ISA backplane, which provides power and a connection to the ISA slots, while USB CDC ASM (12MBit/s) talks to the PC. Madel states he’s also implemented USB 2.0 HS support within the hardware.
The hardware is still in the development cycle, so there are numerous bugs to sort out before he can complete his project. That said, Madel did manage to get his platform to emulate MS-DOS 6.22 to play Monkey Island 1 while playing Adlib music on an Aztech ISA soundcard, as shown in the video above.