Something for Moggy... ( and probably lots of others )

Discussions about Sinclair ZX80 and ZX81 Hardware
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Andy Rea
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Something for Moggy... ( and probably lots of others )

Post by Andy Rea »

coming soon....

Anyway back to the story, what do you get if you Cross a Moggy with a DK'Tronics 4K Character Rom and a ZxPand ?

Lets try it shall we... this first
Image then this Image
followed by this...
Imageand the resultImage
Image.... .... ....Image

what ? how ? you may ask.... well of course i didn't telll you something this little gizmo does the job...
Image
it sits inbetween the zx81 and the ZxPand and allows UDG charcaters to be stored on the ZXpands Ram. This is the first prototype PCB it has 2 bozo's the first was a missing power pin on the chip that i spotted shortly after placing the order... the second... and how in gods name did i forget... was the refresh signal ! anyway the next prototype board is ordered is a little shorter at just 1.5 inches do wont made you ZxPand stickout too far.

QS scamble
Image
galaxians
ImageImage

the controls :lol: :lol: :lol: are very simple.... a 2 way jumper selects between standard UDG i.e 64 characters and there inverts OR chr$128 which gives 128 charcaters or leave the link off altogether to disable UDG

i estimate the sell price to be between 15 to 20 GBP + postage and packing.
what's that Smell.... smells like fresh flux and solder fumes...
Moggy
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Re: Something for Moggy... ( and probably lots of others )

Post by Moggy »

I thought my lights had gone dim tonight, The mad Midlander is at it again!!! :lol:

Nice one Andy. :ugeek: :ugeek:

What with AY,Turbosound, MIDI and now UDG I think this is a fertile time for us zeddy lovers, I might be no sort of games player but I've got to give this little bugger a go!
sirmorris
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Re: Something for Moggy... ( and probably lots of others )

Post by sirmorris »

Image Image oh yeah .. andyyyyy .. oh yeah Image Image
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1024MAK
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Re: Something for Moggy... ( and probably lots of others )

Post by 1024MAK »

Nice :ugeek: 8-) :D

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Lardo Boffin
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Re: Something for Moggy... ( and probably lots of others )

Post by Lardo Boffin »

Although I have no real need for one I am a magpie when it comes to cool things to plug into my computers - any idea when it will be available to buy? :lol:
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nollkolltroll
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Re: Something for Moggy... ( and probably lots of others )

Post by nollkolltroll »

But... How?! I thought the expansion bus was on the wrong side of the ula. Please enlighten us!
Good job though, can't wait to buy it!
/Adam
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Andy Rea
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Re: Something for Moggy... ( and probably lots of others )

Post by Andy Rea »

nollkolltroll wrote: Mon Jul 10, 2017 11:00 am But... How?! I thought the expansion bus was on the wrong side of the ula. Please enlighten us!
Good job though, can't wait to buy it!
The ZXpand is the wrong side of the ula.. the chip on this device recreates much of the ULA's circuitry and provides the missing signals.

It has been designed so that it can be completely.disabled so unnecessary plugging and un plugging is eliminated.

Regards Andy
what's that Smell.... smells like fresh flux and solder fumes...
gozzo
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Re: Something for Moggy... ( and probably lots of others )

Post by gozzo »

ooh, will it work with 'normal' ram expansion or only work with zxpand? i was trying to work out a 'programmable' version of wilf righters chr$16 external thingy, and think i've got it, but as theres software that uses the dk tronics system, maybe thats better...OR does it work the same way? changing the I register to point to high byte of character bitmaps!
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Andy Rea
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Re: Something for Moggy... ( and probably lots of others )

Post by Andy Rea »

gozzo wrote: Mon Jul 10, 2017 12:27 pm ooh, will it work with 'normal' ram expansion or only work with zxpand? i was trying to work out a 'programmable' version of wilf righters chr$16 external thingy, and think i've got it, but as theres software that uses the dk tronics system, maybe thats better...OR does it work the same way? changing the I register to point to high byte of character bitmaps!
I can't guarantee that it will work with other external memory expansions. However.... if your external memory is wrx enabled then in theory it should work.

Yes i believe that all the UDG schemes use the I register to point were in memory the character maps are stored.

Regards Andy
what's that Smell.... smells like fresh flux and solder fumes...
gozzo
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Re: Something for Moggy... ( and probably lots of others )

Post by gozzo »

my chr$16 mod doesnt use any of the zx81's ram, as it has its own ram to store the 'bitmaps' so should work with ANY or even no add on ram if i can find the circuit i drew up a few years back i'll post it here, somewhere..never got round to building it but i think 'in theory' it should work...
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