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This project it still under development.

The basic idea for this project is to add a hard drive via the System bus on the 100/102/200

The circuit is based on a 8255 which controls the hard drive data and control signals.

A 74573 is used to split the ADDRESS and DATA signals and a 138 is used for IO mapping

The 8255 is split into 3 x 8bit ports, one is used for address, CS, RD, WR and RST. The other two port are used for the 16 data bus.