ZXpand with UDG Characters

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
Slipstreem
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Re: ZXpand with UDG Characters

Post by Slipstreem »

Would THIS free font editor be any help? It installs umpteen fonts of its own in a sub-folder that you can open and play with.
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Andy Rea
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Re: ZXpand with UDG Characters

Post by Andy Rea »

Hi Phil, yes they are 8 bytes per character row, top row first, first 8 bytes char 0 , next 8 char 1, next 8 char 2 and so on.

but yeah assci text will do, i can manipulate them and compile it to a binary that i can then load on the zeddy.

so.....anyway......... my progress so far......

things you will need...
1) ZX81 --- Check.
Image
2) ZXpand - Check.
Image
3) Magic gizmo. Check. it's an unbuilt ULA on a zxedge breakout board (nicked from a zxprinter))
Image
Image
Image

And plug it all together and you get...
http://www.youtube.com/watch?v=mRo3-6q8EH8

So how does it work ? the breakout between ZX81 and ZXpand has A0 thru A9 cut, A0 and A1 have an in and an out from the gizmo, A2 thrui A9 only have outputs on the ZXpand side of the 1K resistors brigdging the cut tracks, (just like in the ZX81 between ROM and RAM) D0 thru D5 and D7 also go into the gizmo. then at every rising edge of the /RD line the data bus is sampled and then during a refresh (/refrsh low) and A14 low (this may change) the alternate address is fed to the ZXpand side of the gizmo. the gizmo also emulates the character line counter but not by using halt and nmi, instead it fully emulates the hsync, nmi latch and vsync latch, this ensures complete compatibilty.

things i need to do.
add a select line for UDG/UDG128.
add a select to switch off completly (to allow normal WRX)
maybe allow a more creative memory select (at the moment with only A14, it's active at 8-16K and 32-48k)

so erm yeah thats about it for now
what's that Smell.... smells like fresh flux and solder fumes...
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Andy Rea
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Re: ZXpand with UDG Characters

Post by Andy Rea »

Slipstreem wrote:Would THIS free font editor be any help? It installs umpteen fonts of its own in a sub-folder that you can open and play with.
Cheers i shall take a look at that. i'll probably be able to make some use of it :lol:

Andy
what's that Smell.... smells like fresh flux and solder fumes...
sirmorris
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Re: ZXpand with UDG Characters

Post by sirmorris »

...

....

WOW!

Congrats, Andy! And I must say after meeting you at the weekend I'm not surprised that you got this going - I can honestly say openly here I've never met a more naturally talented hacker ;¬)
Prime
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Re: ZXpand with UDG Characters

Post by Prime »

Andy Rea wrote:Hi Phil, yes they are 8 bytes per character row, top row first, first 8 bytes char 0 , next 8 char 1, next 8 char 2 and so on.
Phill :) :)
but yeah assci text will do, i can manipulate them and compile it to a binary that i can then load on the zeddy.
Here you go Andy, the complete Dragon Alpha and ZX spectrum fonts, both are 8x8, so should be exactly what you need.
The file is cropped directly from my Dragon Multi-cart source so you'll need to change the FCC directives to whatever your Z80 asm uses, and re-order the character set as needed....
fonts.asm
Dragon Alpha & ZX spectrum fonts
(14.41 KiB) Downloaded 192 times
Cheers.

Phill.
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Andy Rea
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Re: ZXpand with UDG Characters

Post by Andy Rea »

Hmmm i've come across a *slight* problem, qicksilva scramble... its a 2 part loader, looks like the first part sets up the USG's and then loads the second part

HOWEVER it also looks like it copies some of the character data from the Zeddies rom, which when you have ZXpand plugged in is the ZxPands enhanced rom with-out character data.... so how to copy from the real rom whilsts still been able to load second part from ZXpand ???

i don;t think it can be done, but i reckon a new loader could be hacked together that loads a complete character map after the original loader has done it's bit and then load the second part...

think i'll go try it... :D

Andy

EDIT.... sucess, modified the loaser program to load the charset data inmediatly before loading the main game.
what's that Smell.... smells like fresh flux and solder fumes...
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Andy Rea
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Re: ZXpand with UDG Characters

Post by Andy Rea »

serious for a moment, is there any need to allow UDG character maps at memory locations OTHER than $3000 - $3FFF :?:

Andy

LOLz only just noticed that was a serious typo..... should have been $2000 - $3FFF
Last edited by Andy Rea on Fri Dec 02, 2011 8:50 pm, edited 2 times in total.
what's that Smell.... smells like fresh flux and solder fumes...
sirmorris
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Re: ZXpand with UDG Characters

Post by sirmorris »

I can't think of any.

C
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siggi
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Re: ZXpand with UDG Characters

Post by siggi »

Andy Rea wrote:serious for a moment, is there any need to allow UDG character maps at memory locations OTHER than $3000 - $3FFF :?:
I once wrote a game, which uses UDGs stored at $2000 ...
http://www.rwapsoftware.co.uk/zx81/soft ... terc-u.zip

Siggi
My ZX81 web-server: online since 2007, running since dec. 2020 using ZeddyNet hardware
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Andy Rea
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Re: ZXpand with UDG Characters

Post by Andy Rea »

Anyways typo's asside, i've got another working prototype, you need to slightly modify your zeddy (cut 9 tracks near edge connector and rewire them to the rom address lines) :? oh and you need a very custom ULA... so that you can switch between UDG and HRG in the 8-16K memory region.

Andy
what's that Smell.... smells like fresh flux and solder fumes...
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