Manawyrm/ISASTM

STM32-based ISA-over-USB-adapter

HTML

135

30 commits

updated Mar 19, 2021

See the code

See what people are saying

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Ask HN: Who's still keeping a DOS machine up because the business depends on it?

This looks quite interesting: https://www.reddit.com/r/vintagecomputing/comments/jbaw38/is... (2020) https://github.com/Manawyrm/ISASTM/

0

Sep 25, 2026

README

ISASTM

Photo of ISASTM PCB

Overview

ISASTM is an ISA host using a STM32H743 CPU, 32 MiB SDRAM and USB 2.0 Full-Speed / High-Speed.
It can enable ISA cards to be used inside a VM or even emulate an x86 PC internally with an external ISA bus.

The card is designed to be used with an ISA backplane, which supplies power and connects the ISA slots.
The design is optimized for automated assembly at JLCPCB.

Errata Rev. A

  • Signal integrity issues, level shifters seem to drive the bus too hard. Maybe 33R series resistance.
  • Reset line is missing a pull up on the ISA bus/HV side
  • USB 2.0 High speed (480 MBit/s) untested, might not work.

Additional info

Firmware
Schematic

Twitter: Project thread

Credits

Thanks to @Toble_Miner for layouting the PCB!

isa
retro
stm32
usb

Contributors

Manawyrm

15 commits

TobleMiner

15 commits

Manawyrm/ISASTM

STM32-based ISA-over-USB-adapter

HTML

135

30 commits

updated Mar 19, 2021

See the code

See what people are saying

SourceMessageScoreDate

Ask HN: Who's still keeping a DOS machine up because the business depends on it?

This looks quite interesting: https://www.reddit.com/r/vintagecomputing/comments/jbaw38/is... (2020) https://github.com/Manawyrm/ISASTM/

0

Sep 25, 2026

README

ISASTM

Photo of ISASTM PCB

Overview

ISASTM is an ISA host using a STM32H743 CPU, 32 MiB SDRAM and USB 2.0 Full-Speed / High-Speed.
It can enable ISA cards to be used inside a VM or even emulate an x86 PC internally with an external ISA bus.

The card is designed to be used with an ISA backplane, which supplies power and connects the ISA slots.
The design is optimized for automated assembly at JLCPCB.

Errata Rev. A

  • Signal integrity issues, level shifters seem to drive the bus too hard. Maybe 33R series resistance.
  • Reset line is missing a pull up on the ISA bus/HV side
  • USB 2.0 High speed (480 MBit/s) untested, might not work.

Additional info

Firmware
Schematic

Twitter: Project thread

Credits

Thanks to @Toble_Miner for layouting the PCB!

isa
retro
stm32
usb

Contributors

Manawyrm

15 commits

TobleMiner

15 commits

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