What is it?

This is a special version of ZXpand which has been designed for use with the Minstrel 3 computer.

It overrides the BASIC LOAD and SAVE instructions to use a full size SD card. It also adds three new commands:

• CAT (to get a directory listing)
• DELETE (to delete a file)
• CONFIG (to change options).

Those commands replace three lesser used ZX printer commands. They are already marked on the keyboard overlays.

This version does not feature it's own ROM or RAM, so cannot be used with a real ZX81.

Why did you make it?

ZXpand was originally designed and produced by Charlie Robson (sirmorris). Those are now out of production and difficult to get hold of. The Minstrel ZXpand is produced with his approval and assistance to work only with the Minstrel 3.

What makes it special?

This version has been simplified to reduce size and cost, making use of the 32K RAM already present in the Minstrel 3. A replacement ROM is provided for the Minstrel 3, and a wire link attached to the ROM jumper block to select the ZXpand ROM when required.

The joystick port supports standard 9 way D Atari / Commodore joysticks, and can be read in three ways:

• The ZXpand port, which is supported directly by several games
• A replacement INKEY$ function, where the joystick movements are reported as cursor keys (or can be configured for any keys)
• A Kempston compatible interface reports the joystick movements on port 31

The Kempston port and the ZXpand can be disabled by two jumpers. The ZXpand can also be disabled in software

A 6 pin FTDI header is provided. This can be used in conjunction with the ZXpand to load files into the Minstrel 3 via serial from a PC.

An SD card is required. The older, slower and lower capacity the better. Avoid microSD in adapters if you can, they are not very reliable.

The SD socket is supplied pre-soldered onto the PCB. The remainder of the kit is standard through hole parts.

Which versions are available

This is available as a kit or assembled and tested. None of these versions will suit anything inside a ZX81 case. The ROM jumper needs to be connected to the Minstrel 3 jumper block, so it is only suitable for stand alone SBC style systems.

There are three options to suit your system:

• Vertical pin header - this version is designed to mount vertically, either in the Minstrel Expansion Bus backplane, or in the Minstrel Expansion Bus socket on later Minstrel 3 boards. This is the recommended configuration.

• Horizontal soldered - this version has a pin header which is soldered directly to the Minstrel 3 edge connector, or the pass through connector on the Minstrel Expansion Bus. This provides a very reliable connection, but is not easily reversible.

• Horizontal edge connector - this version is as above, but instead uses an edge connector. This can easily be removed, so is more adaptable, however the edge connectors are not as reliable as the pin headers or soldered connections.

The horizontal versions include 10mm nylon pillars and screws matching those used on the Minstrel 3 kits.

The standard kit comes with a socket only for the 40pin microcontroller. Optionally sockets are available for the logic chips. (the ROM goes into the socket already present on the Minstrel 3).

What is not included

This kit does not include an SD card, Minstrel computer, ZX81, backplane, joystick or anything else other than the Minstrel ZXpand itself.