SC127, v1.0, User Guide

SC127 is a Compact Flash interface for the Z50Bus.

This card provides an 8-bit IDE interface via a 40-pin male header. In theory, you could connect other IDE devices, not just the recommended Compact Flash adapter module (shown above).

As this is a very simple interface, which uses the processor bus directly, without buffering, the IDE interface should not be extended for than a few inches and only carefully selected devices should be connected. In general, it is best to only use this interface to connect a Compact Flash card.


The I/O address of this card can be set with jumper, JP1. Two address ranges are available: 0x10 to 0x17 and 0x90 to 0x97.

Current software assumes the I/O address range is 0x10 to 0x17. It is intended that future Z50Bus developments will require the use of address range 0x90 to 0x97.


The device plugged into P1 (20 pin, 8-bit IDE) can be either self powered or it can take power from SC127. The recommended Compact Flash adapter module must be powered from SC127.

As it is very likely the connected device will need to be powered from SC127, JP2 has a track connecting its two pads. Thus the jumper header and jumper shunt are optional. If fitted, the track between the pads of JP2 must be cut. This track is on the component side of the PCB. If JP2 is present then fit a jumper shunt to provide power the to IDE connector, P1.


It is assumed SC127 will be used with CP/M. This requires a prepared Compact Flash card. Instructions to install CP/M 2.2 on to a Compact Flash card can be found here.

The version of CP/M for this card, together with SC118 (Z80 processor card) and SC125 (Serial card), is detailed here.

If you are using the Small Computer Monitor firmware then CP/M can be started with the command “CPM”.

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