1. Not old. Vintage. :)
Timothy Kline

Cumulus: SD card peripheral for Oric-1 and Atmos computers 2020-07-08

Cumulus is an SD card peripheral for Oric-1 and Oric Atmos computers

  1. Timothy Kline
    Cumulus is an SD card peripheral for Oric-1 and Oric Atmos computers that emulates the complete Oric Microdisc system.


    Oric-1 and Oric Atmos computers (like many others from the 80s) do not have a built-in floppy controller IC. Instead, the Microdisc peripheral contains a controller card with a WD1793 that connects to the Oric expansion port. One could use a standard SD card floppy emulator (e.g. TFE) with the with a Microdisc controller card, but the Microdisc system itself can be very difficult to obtain.

    Instead of emulating only the floppy drive, Cumulus emulates the whole Microdisc system. There are significant advantages to emulating the controller together with the drive. For example, SD card access times are no longer critical as the emulator is in complete control of when the floppy disk surface is accessed. MFM conversion of data is no longer necessary as the floppy disk interface is eliminated.


    • Read/write access for Oric-1 and Atmos computers.
    • Connects to the Oric expansion port (over CumuluBus).
    • Compatible with existing software written for the Oric Microdisc.
    • On-board support for DSK images. No conversion on PC necessary.
    • Emulates multiple drives.
    • Color LCD and 5 buttons for user interface.
    • Full FAT32 support (incl. long file names and directories) for the SD Card. SDHC support.
    • Firmware updates can be made through SD Card.
    • Completely solderless installation.
    • CumuluBus (bus buffer) + 80-conductor IDE cable for very high signal integrity.
    • PIC18F46K20 MCU @32Mhz, Xilinx XC95144XL CPLD. Double-sided PCB.