Sharp X68000 RAM+MIDI expansion board (CZ-PXM1A)
The Sharp x68000 SRAM + MIDI card (CZ-PXM1A) by Polykubos adds MIDI functionality to Sharp x68000 systems and provides up to 8 MB of RAM (per card).
Two Polykubos cards can be installed in Sharp x68000 machines with at least two expansion slots, allowing for a total of 12 MB of RAM.
The card fits into a free expansion slot (both slots are compatible thanks to the use of 3.5mm Type A jacks instead of standard MIDI DIN connectors), and compatibility has been tested with Sharp x68000 CZ-6xx series systems (Classic, ACE/ACE-HD, PRO/PRO-HD, EXPERT, EXPERT II, and XVI).
It is based on an FPGA-type component, which can be reprogrammed and updated. Owners of the Polykubos x68000 SRAM + MIDI card can update it themselves (if they have the necessary equipment) or send the card to the Polykubos store for an update (the owner covers shipping costs to Polykubos as well as return shipping and handling fees).
Current Hardware version : Rev1.0
Current FPGA firmware version : 1.2
updated on 26th of July 2025
ChangeLog
- April 2025 - FPGA Firmware 1.0 : Initial version
- April 2025 - Hardware Rev1.0: Initial version
- June 2025 - FPGA Firmware 1.1 : Implementation of the click counter in the YM3802. Some games (like Mahou Daisakusen) rely on the click counter for timing to play MIDI music. This is is what is included in this version as well as an overall tidy up of the code
- July 2025 - FPGA Firmware 1.2 : Fixes bug discovered in Final Fight when switching audio to MIDI. Assumption was made that a register would enable or disable the interrupt vector register output. Turns out it is only related to the Vector Read input on the YM3802 which is not used by the X68000