Corsham SD card system

SD Card System.

This is a two board system that provides a very inexpensive, flexible, and long-lasting storage option for our KIM Clone , SS-50 based designs, or almost any third party system.

The main board is the Corsham SD Shield. It plugs into an Arduino Mega and provides for insertion of a micro SD card, and also includes a DS3231 based real time clock (RTC). The Arduino does the hard 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. Since the source code is available you can add additional drivers for whatever shields you 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 for the Arduino Mega is also available for download.

SD Card System manual
SD Card Schematic
SD drive Arduino November 2020 source
SD shield tester, set RTC time source Arduino
The Remote Disk Protocol Guide
6502 routines for KIM-1 low and high-level disk access
Also see xKIM extended KIM Monitor