ZX80 Core - new ZX80 motherboards

[PokeMon]

No, there is no change necessary to use PAL or NTSC.
It can be choosen in the ZX80CORE with a simple diode to assemble or not.
This diode is not in the assembly set now but any schottky diode would do (BAT42, BAT46, BAT54).

[PokeMon]

So I think in end of march I would be able to deliver a transparent case for the ZX80CORE made with acryl.
This way it will the best way for presentation of the nice board and I will deliver a driver for controlling the LEDs as well.
They are now automatically controlled via the signals but would be possible to use this inside programs to indicate something.

Now I have only the ground part where the ZX80CORE is mounted on, the top cover is still in production and will be shown on Mahlerts as well.
Unfortunately I am not there but one of the german guys will take some new stuff from me to be shown there.
So I will present picture of the top cover soon, latest in end of march.

The price for the case will be around EUR 30.00 / GBP 25.00. If I know how many people are interested in having one I can do a proper calculation. I think and hope there is maybe enough interest for about 10 cases. Acryl is a quite cheap material but it is expencive to bend the edges to have a nice look. The preparation of the material is quite more expensive than the material itself and counted in meters. The board is mounted with (white) screws and the acryl parts have drills and threads and some bar spacers. The top cover will be mounted with white screws as well. The front part with the keyboard membrane can be fixed with black screws like shown on the picture but these can be omitted as well and just use the bar spacers. The bar spacers will be with white color, in the moment I have them only in black which looks not so nice.

In the prototype I was not sure if the top cover should be justified with the ground plate or better to leave some millimeters free. That's the reason why I didn't place the ZX80CORE exactly in the middle to have both sides different to choose the better look. So any feedback or proposals are welcome as well.

Now the pictures of the top view:

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IMG_7238kk.JPG (134.92 KiB) Viewed 2996 times

IMG_7241kk.JPG (147.84 KiB) Viewed 2996 times

[PokeMon]

And the view of the bottom:

IMG_7244kk.JPG (195.83 KiB) Viewed 2997 times

IMG_7245kk.JPG (207.28 KiB) Viewed 2997 times

IMG_7246kk.jpg (196.95 KiB) Viewed 2997 times

PS: The ground plate will be shorter later and justified with the edge connector to safely add modules at the back.

[blittled]

Is the case going to be a clear version of the ZX80 case?

[PokeMon]

Yes - but without the "hat" in the middle of top cover.
Will put some pictures here in 2 weeks again when finished.

[blittled]

I noticed the ROM image at ROM switch 4 is the ROM for the ZX80. I couldn't find the ZX81 ROM. What switch position is it located at? Thanks.

[PokeMon]

So here it the ROM contents I usually ship with the 32k version (28C256).
4 => ZX80 (4k ROM)
5 => ZX80 (double programmed)
6 => ZX81 (8k ROM)
C => H4TH (Forth - still not working in my ZX80CORE, have to find out why)
E => ASZMIC (4k ROM)

All these position active write protect, when subtracting 4 it is without write protect.
ZX81ROM does not work properly without write protect (PRINT statement makes it hang). This is due to errors in ROM code.

Please note that in the smaller 28C64 (8k version) there is no room for both ZX80 and ZX81 image.

[blittled]

Thanks Pokemon. Also thank you for all your work you put into the ZXCore. I nearly got mine running. There seems to be a loose connection somewhere since anything that is displayed may disappear from the screen randomly when I move the board. I think there is a cold connection in the parallel to serial video out circuitry that is causing it.

[PokeMon]

Does it come back or does it hang ?

[blittled]

It does come back.

When I pressed IC11 or 12 I could get characters to appear but sometimes the top and bottom scan lines of the characters were missing. Sometimes the inverted characters were not inverted. After changing the ROM switch to different settings and back to 4 the screen showed no characters when powered up. I re-soldered IC11 and 12 and I still get the blank screen but when I press on IC9 I sometimes get the "K" but it isn't inverted. I'm not the best at soldering so I am pretty sure I have at least one cold solder joint that I haven't spotted that is causing this.