The ISA PioMEMO Extension board is a new, software-defined extension board for the original PC:
Current Functionality
- Memory emulation with 16Kb Address granularity:
128Kb of RAM can be emulated from the Pi Pico internal RAM with No Wait State. We can emulate the whole 1Mb of RAM address space from the PSRAM. (With 6 Wait Stated minimum added) EMS Emulation of Up to 6/7 Mb. (Only 4Mb for the moment as using the LoTech EMS Driver) Memory emulation is used to add 4Kb of "Private" memory for the PicoMEM BIOS Usage. 4Kb of RAM is also added for disk access (Or other) 512b only is used for the moment.
- ROM Emulation for its internal BIOS and custom ROM loaded from the MicroSD. (Custom ROM not implemented yet)
The Board has its own BIOS, used to automatically detect/Extend/Configure the RAM emulation and select Floppy/Disk images.- Floppy and Disk "emulation" from .img files stored in uSD through FasFs and DosBOX int13h emulation code.
Emulate 2 Floppy and 4 Disk (80h to 83h), Disk up to 4Gb (More later)- USB Mouse support through a USB OTC Adapter. (Micro USB to USB A or USB Hub)
- POST Code on Rev 1.1 and 1.11 (Port 80 Display in Hexa) through this device : https://www.sparkfun.com/products/16916
- ne2000 network card emulation via Wifi is working on boards with a PicoW.
- USB Joystick for PS4 and Xinput controllers.
- NEW: Adlib using a PCM502 I2S module.
Future Functionality
- There is already a mechanism implemented, so that the Pi Pico can send command to the PC, we can have the Pi Pico taking "Virtually" the control of the PC.
This can be used to perform ROM/RAM dump, Disk/Floppy DUMP/Write, display/kb redirection....
- More USB Host to be added (Keyboard, MIDI...)
- Bluetooth support for device like Gamepad may be added.
- Use of the Qwiic connector for more information display (OLED), maybe RTC and other.
I don't have an original PC from that era, so unfortunately, this is not something I can try right now. Given the extensibility thanks to the software-defined nature of this card, I'm really wondering what this little thing will achieve in the future.
Adrian Black covered this card in a recent video:
