Sinclair ZX80 / ZX81 / Z88 Forums

When compiling I get this error. (real ZX81 not emulator) I apologize Fred, it was my fault, the HTERM.BLK file was incomplete, missing a page, hence the compilation error. I have already fixed the issue and updated the zip package above. In any case, the ARX.F79 and EDARX.F79 files were compiled c...

Forth variant: TF79 (Requires UDG or HGR extension) You probably know this famous one-line BASIC program from the Commodore 64 : 10 PRINT CHR$(205.5+RND(1)); : GOTO 10 Here my version for the TF79: : LAB CR BEGIN 47 45 2 RND * + EMIT AGAIN ; As it uses special characters, it must be run with UDG mo...

I bring here Paul Farrow's Enhanced ARX Driver , ported to the TF79. The main advantage of the ARX driver over the WRX, especially for those using the UDG4ZXpand board, is being able to switch from the text terminal to the graphics terminal without having to worry about jumpers or switches. However,...

Forth variant: TF79 (Requires the HGR extension)

Reference: https://en.wikipedia.org/wiki/Truchet_t ... er-circles


Note how screen 7 was used to load the program, since screens 1 to 6 are occupied by the high-resolution screen.

We saw previously that the snake becomes slower as it grows and the main reason for this is the DRAW-SNAKE routine: : DRAW-SNAKE LENGTH @ 0 DO I SNAKE-X C@ I SNAKE-Y C@ DRAW-BLACK LOOP LENGTH @ SNAKE-X C@ LENGTH @ SNAKE-Y C@ DRAW-WHITE ; Note that the snake is completely redrawed for each cycle, whi...

So it sounds like on the UDG4ZXpand there is a physical jumper that must be set to enable 128 character mode. For Chroma 81, the RAM in the 8K-16K region (if enabled) is always capable of 128 character mode and it is bit 0 of the I register that determines whether to use 64 or 128 character mode. I...

msknight wrote: ↑Mon Mar 18, 2024 4:21 pm Anyone know how to make/get the piggyback board please?

Here: viewtopic.php?p=49047#p49047

I recall there was an UDG4ZXpand board (which I think Andy created also but correct me if I am wrong). I'm wondering if this will make the 8K-16K RAM provide by the ZXpand ARX compatible. Does anyone know? Yes, all external RAM connected to UDG4ZXPAND is capable of providing UDG xor WRX. Selection ...

Excellent! ARX is a great option to use with Brazilian TKs clones, which do not tolerate WRX very well. As soon as I have time I will test it on my TK85. The ARX display technique devised by Andy Rea in 2006 is fascinating in that it could have given true high resolution graphics back in the day usi...

KEY is missing but INKEY isn't, so you can define KEY as

: KEY BEGIN INKEY ?DUP UNTIL ;

Take a look at chapter 16 of the manual, it will help a lot!