SCSI-1 Emulator for 8-bit Acorn computers such as the BBC Master and BBC Model B
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BeebSCSI is a Micro SD Card based SCSI storage emulation for the Acorn 8-bit range of microcomputers including the Acorn BBC Model B (with ADFS) and the BBC Master 128.

Please see for detailed documentation on BeebSCSI

The project is divided into several sections:

BeebSCSI_AVR - This is the AT90USB1287 microcontroller firmware (written in GCC)

BeebSCSI_CPLD - This is the Xilinx XC9572XL CPLD firmware (written in ISE Verilog)

BeebSCSI_KiCAD - This folder contains the KiCAD schematics and PCB designed (V7_6 and above)

BeebSCSI_OpenSCAD - This folder contains a 3D printable case designed in OpenSCAD

BeebSCSI_ROM - This folder contains the 6502 assembly code for the BeebSCSI ROM

BeebSCSI_Utils - This folder contains BBC BASIC utilities for BeebSCSI


Originally Acorn provided a SCSI solution based on 3 individual parts: The Acorn SCSI host adapter, the Adaptec ACB-4000 SCSI adapter and a physical MFM hard disc (a ‘Winchester drive’). Later, as part of the Domesday project (in 1986), this was extended to include the AIV SCSI Host Adapter (designed to be connected internally to a BBC Master Turbo) and the Philips VP415 LaserVision laser disc player with SCSI-1 support.

BeebSCSI 7 is a credit-card sized board that provides a single-chip implementation of the host adapter board (both original and AIV) using a modern CPLD (Complex Programmable Logic Device). In addition, an AVR Microcontroller provides a complete SCSI-1 emulation including the vendor specific video control commands of the VP415.

Rather than using a physical hard drive, BeebSCSI uses a single Micro SD card to provide up to >64Gbytes of storage with support for either 4 (ADFS) or 8 (VFS) virtual hard drives (or ‘LUNs’) per card. In addition, in the BBC Master, two BeebSCSI devices can be attached, one internal and one external, providing 12 SCSI LUNs (hard drive images) simultaneously.


Please see for detailed documentation on BeebSCSI


BeebSCSI is written and maintained by Simon Inns.

Software License (GPLv3)

BeebSCSI is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

BeebSCSI is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with BeebSCSI.  If not, see <>.

Hardware License (Creative Commons BY-SA 4.0)

Please see the following link for details:

You are free to:

Share - copy and redistribute the material in any medium or format Adapt - remix, transform, and build upon the material for any purpose, even commercially.

This license is acceptable for Free Cultural Works.

The licensor cannot revoke these freedoms as long as you follow the license terms.

Under the following terms:

Attribution - You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.

ShareAlike - If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.

No additional restrictions - You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.