Corsham SS30 SD Card System

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Reproduction Corsham SS30 SD Card System


Shown here is the SD Shield/Mega connected to a parallel card.  This combination is simply plugged into the appropriate slot of your SS50 computer.  No other wires are needed.


This is an Arduino Mega 2560.  The SD shield is plugged into this board.  The Mega gets its power from the parallel cable connected to the shield.


Differences between the Original and Reproduction

The major difference in this board from the original board is the use of a ground plane/pour in all open space on the board. 



The SD Card system is intended to replace both floppy and hard drive systems.  Its speed is faster than a floppy but slower than a hard drive system using an SS30-IDE controller. Floppy images can be downloaded from the FLEX user group and transferred to the SD memory card.  These images can be mounted by a utility. You may have up to four images mounted at a time as drives 0,1,2 and 3. The RTC on the shield can the used to set the date for FLEX.

The main board is the SD Shield.  It plugs into an Arduino compatible Mega 2560 and provides for insertion of a micro SD card.  The shield includes a DS3231 based real time clock (RTC) and an easy to replace battery.  The Arduino does the work of providing an interface between the host processor (6502, 6800, 6809, etc) and the SD card and RTC.  It connects to the host via a ribbon cable.

The board also contains three LEDs used for status, a RESET switch, a four position DIP switch, a DS3231 RTC, backup battery, and it maintains the Arduino Mega headers so additional shields can be placed on top.  The source code is available for you to add additional drivers for whatever shields you want to add.  Want to add an LCD shield that displays which files are mounted?  Just plug in the shield and modify the user interface class in the source code.  Only one of the DIP switches has a defined purpose, so the rest are free for you to add your own logic.

The protocol between the host and the SD Card System is completely defined in The Remote Disk Protocol Guide available for download below.

The source code to the Arduino can also be downloaded.

In order to use this card on an SS-50 based system, you will also need a parallel card.  It is recommended to use the Corsham parallel card since connection is straight forward only requiring a ribbon cable to be plugged in between the Arduino/SD Shield and parallel board.  If you elect to use another parallel board you will have to construct your own cable to connect the parallel board to the SD shield.

Ordering Options

Assembled with Mega 2560 and Parallel Board  – The quickest and easiest way.   Includes the shield plugged into an Arduino Mega compatible controller, the parallel board, the cable to the parallel board, and an SD card with a bootable image ready to go.  You will need to insert the SD card in a PC to configure it.  The SD card contains a folder for the 6800 and one for the 6809.  The contents of the appropriate folder must be moved to the root of the SD card.  If you spec which CPU you want to use we will send you the appropriate SD memory card and the SD system will be ready to boot as soon as you plug it in.

Assembled Shield – You need to acquire an Arduino mega compatible controller, program it from the Arduino sketch, acquire a parallel board, and construct a cable to connect the parallel board to the SD shield.

Bare PC Board – You need to be able to solder surface mount components.  There are two surface mount components, the SD Card socket and RTC.  With a good soldering iron and good soldering skill these two parts can be installed by hand.


Corsham SD Card System User Manual.pdf 

Corsham SD Shield Schematic.pdf   The schematic is included in the User Manual.

The-Remote-Disk-Protocol-GuideV1.1.pdf   Only needed if you want to modify the code or port it to a new host.

Corsham Arduino SD Shield Code This is the Arduino sketch to be loaded on a new Mega 2560.  You need to download the Arduino IDE to work with this code.

Corsham Arduino Test Code  If you are having trouble with your SD Shield, this test program will give diagnostic messages to a terminal connected to the Mega 2560 USB port. You need the Arduino IDE to load the program to a Mega 2560.  After running this program, you have to reinstall the Corsham SD shield code.

Corsham SD Memory card image  Download, unzip and place the contents on a micro SD card.  You then need to move the contents of the 6800 or 6809 folder to the root before the SD card is usable.



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Price List Hardware

SD-Card-System-ASM Included assembled SD shield, Mega 2560, parallel board, ribbon cable and SD card preloaded with 6800 and 6809 images. $119
SD-Shield Assembled SD Shield $40
SD-Shield-Board SD Shield board - bare $8

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