An SD card disk drive and joystick interface for the Minstrel 2 and Minstrel 3 computer kits (not suitable for other ZX80 or ZX81 machines)Designed by Tynemouth Software in United Kingdom
What is it? This is an SD card disk drive and joystick interface for the Minstrel 2 and Minstrel 3 computers. It is a special cut down version of the ZXpand, only suitable for the Minstrels. It was...Read More…
This is an SD card disk drive and joystick interface for the Minstrel 2 and Minstrel 3 computers. It is a special cut down version of the ZXpand, only suitable for the Minstrels. It was designed in co-operation with Charlie Robson/sirmorris, and produced with his approval. It has been specially designed to work with the Minstrel, and is not suitable for use with other ZX80 or ZX81 machines or the Minstrel 4th.
One of the limiting factors of the Minstrel computers is having to load programs from cassette, or over the cassette interface. This gives a way to load programs directly from an SD card into the Minstrel. A full ZXpand or ZXpand+ could be used, but these can be difficult to get hold of, so I have built a version that will be available to Minstrel owners.
To reduce costs and simplify the design, the ROM and RAM which are usually on the ZXpand board have been omitted as these are already present on the Minstrel. This does mean it will not work with other ZX80 or ZX81 machines. I might say that one or two more times, just to be clear.
There is a joystick port which operates in three different ways to increase the chance it will be support.
ZXpand mode The ZXpand interface supports a two stage joystick read command, supported in some new titles
INKEY$ mode The ZXpand overlay ROM includes a modified version of the INKEY$ command which checks for joystick input and converts that into keypresses. This defaults to the arrow keys (5678) and 0, but can be remapped in software. Any BASIC games that use INKEY$ should work in this mode
Kempston mode The Minstrel ZXpand is also mapped as a Kempston joystick, which is supported by various title which read a kempston joystick at address 0x31
A ROM is supplied which contains a ROM which adds several commands to BASIC. On the later 8K Floating Point BASIC upgrade to the ZX80 and on the ZX81, these replace the ZXprinter commands (LLIST, LPRINT, COPY), which can still be accessed by disabling the ZXpand with a jumper or by a command.
CAT This shows a listing of the files in the current directory
DELETE Use this to delete a file on the SD card
CONFIG This is used to change options on the ZXpand
In addition, LOAD and SAVE will now read and write to the ZXpand, but you can revert to the cassette interface by omitting a filename (e.g. LOAD "")
The ZXpand can be set to automatically load a program on power on or reset. This can be a menu program, such as ZXpand Commander, which is a menu program for the ZXpand and allows you to browse the SD card using the joystick or keyboard and run programs from there. ZXpand Commander requires NMI slow mode support, so only runs on the Minstrel 3 in ZX81 mode.
The ZXpand design is not open source, so I will only be providing the firmware pre-programmed as part of the kit or built version, and no schematic will be included in the manual. As such, there is no PCB only option at the moment.
You can order a Minstrel ZXpand as a kit or a complete, built and tested unit. All versions include a programmed microcontroller and a replacement ROM for the Minstrel 2 or 3. The SD card socket is surface mount, and comes pre-soldered to the PCB in all versions. All other parts are standard 0.1" pitch through hole parts.
PCB + Kit A kit to build a Minstrel ZXpand.
Assembled and Tested An assembled and tested board.
Looking for PCB and programmed parts only - see the separate listing for Partial Kits
There a are a few build options
Sockets for PIC only The standard kit comes with only a socket for the PIC micocontroller. Other chips are soldered directly to the board.
Sockets for all chips If you wish, you can have sockets for all the ICS on the board.
Expansion pin header It is recommended you use the supplied dual row pin header to solder the Minstrel ZXpand directly to the Minstrel as a permanent installation. A single wire link (to select the ROM overlay) needs to be wired from the Minstrel ZXpand to the Minstrel ROM select jumper block. This can be placed under the board so as not to be visible.
Expansion edge connector (uncut) If you wish, you can use an edge connector on the Minstrel ZXpand board to allow it to be removed. Edge connectors are no longer available in the correct number of pins, so the supplied part will have to be cut down. The ROM select link wire will have to be detached each time it is to be removed.
SD card An SD card can optionally be included with some sample software to try for you to try.
There are various versions of the Minstrel ZXpand overlay ROM, all of which are included on the supplied ROM chip, and can be selected via the ROM jumpers
4K ZX80 Integer BASIC with no ZXpand support
4k ZX80 Integer BASIC with ZXpand support
8K ZX80 Floating Point BASIC with no ZXpand support
8K ZX80 Floating Point BASIC with ZXpand support
8K ZX81 BASIC with NMI support and no ZXpand support (Minstrel 3 only)
8K ZX81 BASIC with NMI support and ZXpand support (Minstrel 3 only)
Full details are provided in the build guide, a printed version is included with the Minstrel ZXpand and an electronic copy is available below.
My thanks to Charlie Robson / sirmorris for his support and cooperation with this project.
No Minstrel 2 or 3 computers are included. See elsewhere to order yours.
Did I mention this will only work with Minstrel 2 or Minstrel 3 boards. It will not work with other ZX80 or ZX81 boards, or the Minstrel 4th.
|Shipping Rate||Ships From||First item||Additional items|
DHL: DHL Parcel [Tracked]
DHL Parcel tracked series. Delivery 2-3 days after dispatch.
Randall | Feb. 10, 2020
John | Feb. 6, 2020
Kim | Jan. 14, 2020
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