I had some discussions with Siggi about the ZX-deluxe and made some improvements and now have a working prototype of the ZX-deluxe+. The specs are:
-Integrated full moving keyboard with cherry keys.
-Zxpand SD card drive.
-Joystick interface which can be reconfigured to every key..
-Internet interface Zeddynet with WIZ8121MJ module.
-Why Wait ? Circuit for 10% speed gain. Can be switched off.
-M1-NOT circuit to load machine code above address 32768. Can be swiched off.
-Modern DC-DC converter from Recon for a stable and cool power supply.
-100% compatible with the standard ZX81.
-Crisp and stable composite video out signal.
-2x jack connections for saving and loading old tape images.
-ZX81 compatible edge connector.
-6 easy to adjust switches for inverse video, Border, NTSC/PAL, ROM selection and more.
-Extra connection on PCB for connecting another keyboard , but why should you?
-Ear and Mic input and output to load from tape cassette if needed.
-Power ON / OFF switch
-Zxpand ROM overlay on/off switch to go to standard ZX81 mode or use the SD card Save and Load routines.
I have made this design because I wanted a single board ZX81 computer with all the improvements in one compact design. It is bigger then the original ZX81 (24.5cm x 22 cm) but still not to big.
The ZX-deluxe is in its prototype stage and I was wondering if there are others who would be interested in this design. I can offer it as a building kit and against a higher price a completly build one. All in all it will be more expensive then the standard ZX-deluxe but will include a better Keyboard and the Wiznetmodule for Zeddynet.
You only will have to cut out all the keyboard stickers with a scissor. It will be delivered with a printed keyboard on transparant sticker sheets but you have to cut the keys out yourself.
If it is 100% compatible then perhaps the 2X Rom could help for a faster BASIC?
The latest version can be found on this page..
Having burned it to an EPROM yesterday I can confirm it does offer a most usable speed boost.
But there is a small catch. The zxpand does not work together with the Big Bang rom, it should be patched to do this I presume. But there is a way around this. Just load the program you want with the ZXpand and after it is loaded and the computers is in the K cursor mode switch off the ZXpand ROM overlay with the switch on the PCB and now the Big Bang rom is active and you have the speed gain.
If there are enough interested in getting this computer I can make building kits within a month, ready made computers only when asked will I produce them one at the time. The price of the building kit will be around 200 Euro but that is with the Wiznet module and all the other needed parts. A ready build one will be around 275 and garantees you get a working computer. But you can save on this by doing it yourself. But remeber it is a lot of soldering, more then 800 solder connections.
I am very interested in a PCB only. I have the MX switches, keys, wiznet etc.
Please PM me about the conditions.
Kind regards Paul
Also the Zxpand rom was made for the ZXdeluxe. Furthermore there must be the right combination used of 74LS and HC parts otherwise it will not work. So only kits or completly build.