Search found 35 matches

by Mustermann
Sun Oct 04, 2020 1:47 pm
Forum: Hardware
Topic: Top Ten Hardware Mods....
Replies: 9
Views: 4894

Re: Top Ten Hardware Mods....

The RAMKEY of Wilf sounds quite interesting to emulate key presses controlled by a joystick. The hardware is quite clear to me.(Even if I am planning a different implementation) Assembler code is also understandable. But I am confused about the JSBOOT DECIMAL CODE IN 1 REM LINE Line 16516 is ok. Lin...
by Mustermann
Sat Apr 04, 2020 9:07 pm
Forum: Hardware
Topic: ZX81: From UDG DIY to CHR$128 DIY
Replies: 1
Views: 747

ZX81: From UDG DIY to CHR$128 DIY

There are a couple of ZX81 Hi-Res games existing that are using UDG with 128 user defined characters. This is also named CHR$128. There is not that much information available about CHR$128. One piece of information I found is Kelly Murtas post: https://sinclairzxworld.com/viewtopic.php?t=1495#p15616...
by Mustermann
Tue Mar 17, 2020 8:39 pm
Forum: Development
Topic: Minstrel 3, WRX, UDG and CHR$128
Replies: 9
Views: 5452

Re: Minstrel 3, WRX, UDG and CHR$128

I can do that if you like. There were 8 additional chips at the board and 2 additional at the Vdrive2 adapter needed. Final state.jpg Front.jpg Left.jpg With Vdrive2.jpg This is the output of Vdrive2 info. You may notice changed character set. I copied ROM to RAM and replaced number characters. Vdri...
by Mustermann
Mon Mar 16, 2020 8:53 pm
Forum: Development
Topic: Minstrel 3, WRX, UDG and CHR$128
Replies: 9
Views: 5452

Re: Minstrel 3, WRX, UDG and CHR$128

Jumper implemented. In general I am able to switch 8-16k area now between WRX and UDG RAM. Dungeons of Ymir andf Invaders are loading now, Unfortunately they REALY need entire 8-16k so they are not compatible with my Vdrive2 driver(residing at write protected 8-10k). I assume that I will proof them ...
by Mustermann
Mon Mar 16, 2020 8:04 pm
Forum: Development
Topic: Minstrel 3, WRX, UDG and CHR$128
Replies: 9
Views: 5452

Re: Minstrel 3, WRX, UDG and CHR$128

Thank you Siggi for that hint. I had seen that page, but didn't notice that these programs need WRX RAM between 8-16k. I checked Dungeons of Ymir and Invaders from Fred's page and both gave me puzzled signs. So it seems that it is impossible to run all with one configuration. I will add a jumper to ...
by Mustermann
Sat Mar 14, 2020 5:36 pm
Forum: Development
Topic: Minstrel 3, WRX, UDG and CHR$128
Replies: 9
Views: 5452

Re: Minstrel 3, WRX, UDG and CHR$128

Best of both worlds (WRX and UDG) ! As you may know WRX HRG is using CPU addressing in RAM with I and R Register as pointer to High res data. UDG and CHR$128 use a combination of a line counter and the content of DFILE to address character pattern in RAM. Both are not compatible to each other. So or...
by Mustermann
Wed Mar 04, 2020 9:07 pm
Forum: Hardware
Topic: How to perform a Timex Sinclair 1000 internal memory upgrade?
Replies: 11
Views: 6583

Re: How to perform a Timex Sinclair 1000 internal memory upgrade?

http://web.archive.org/web/20150907000745/http://bitcycle.org/retro/zx81/internal_RAM/ is a quite good how-to to start with internal ram expansion. It is near to the way i started with two differences: I did not cut any line on the board but cut the legs of the socket that doesn't fit to the right ...
by Mustermann
Tue Mar 03, 2020 8:26 pm
Forum: Hardware
Topic: How to perform a Timex Sinclair 1000 internal memory upgrade?
Replies: 11
Views: 6583

Re: How to perform a Timex Sinclair 1000 internal memory upgrade?

Let's start with the assumption that a Timex Sinclair 1000 is identical to a ZX81 except of the size of the RAM. So you may implement the solution I did. This will give you 24k of UDG enabled RAM and 32k of WRX eneabled RAM. ZX81 56k.jpg the design is based on this https://forum.tlienhard.com/phpBB3...
by Mustermann
Sat Feb 22, 2020 9:30 pm
Forum: Hardware
Topic: TS1000 white screen but no K
Replies: 34
Views: 8425

Re: TS1000 white screen but no K

External RAM pack usually disable internal RAM by pulling /RAMCS to high.
So I would expect no difference if internal RAM is missing and external RAM is attached.

Max
by Mustermann
Sat Feb 22, 2020 9:26 pm
Forum: Development
Topic: ZX81 Clone Tynemouth Minstrel 3
Replies: 23
Views: 14147

Re: ZX81 Clone Tynemouth Minstrel 3

Hero(hero.p) tested as working with Minstrel 3 + 56k.

I had some issues with my TFT monitor running Minstrel in PAL mode when Hero was loaded.
This could be solved by switching to NTSC mode(even if I am in Europe).

Max