A PCB for a software-defined ISA card powered by a Raspberry Pi Pico micro-controller. All the logic for interfacing to the ISA bus is done in software.
We can use the ISA Blaster as a USB mouse adapter card. This allows you to use a USB mouse on your vintage DOS PC without the need for an external adapter. This requires the use of:
- The DirtyRat mouse driver for DOS: https://github.com/scrapcomputing/DirtyRatDriver, and
- The DirtyRat Firmware for the Pico: https://github.com/scrapcomputing/DirtyRatFirmware.
- Unplug the ISA Blaster from the motherboard
- Remove any connected USB devices (e.g., mouse)
- Press and hold the small button on the Pico
- While holding the button, connect the Pico to your PC with a micro-USB cable
- The Pico should show up as a mass-storage device
- Copy the firmware to the drive associated with the Pico
- Safely eject the mass-storage device
Gerber files are published in the releases: https://github.com/scrapcomputing/ISABlaster/releases
| Item | # | Description |
|---|---|---|
| Raspberry Pi Pico | 1 | |
| 1x20-pin 2.54mm Female Headers | 2 | For plugging in the Pico |
| 1x20-pin 2.54mm Male Headers | 2 | For the Pico |
| TXS0108EPW 20TSSOP | 3 | Bidirectional level-shifters 3.3V/5V |
| 2x6 2.54mm Male Pin Headers | 1 | For the IRQ selection |
| 2.54mm Jumper | 1 | For the IRQ selection |
| 0.1uF 1206 SMD capacitors | 6 | Decoupling capacitors for the ICs C1-6 |
| 2.2K through-hole resistor 1/8W | 2 | * Better to leave them unpopulated: See "Known Issues" below |
| 3.3K through-hole resistor 1/8W | 2 | * Better to leave them unpopulated: See "Known Issues" below |
| 1uF through-hole ceramic capacitor | 1 | Smoothing capacitor for the board. |
| Horizontal Female USB connector | 1 | For plugging in a USB device. |
| 3-4cm short jumper wires | 2 | For connecting Pico's TP2,TP3 pads to the PCB's pads for the on-bard USB connector |
- Rev0.1 connects MEMR and MEMW to voltage dividers which are made up by the 2.2K and 3.3K through-hole resistors. The voltage dividers can cause issues on some motherboards, so it is better to leave them unpopulated. This will be fixed in a later revision of the board.