Sinclair ZX80 / ZX81 / Z88 Forums

https://www.amazon.it/81-hires-games-1K ... B0C2RW1TH1

The link for italian store. I think all can be reached just replacing ".it" with the appropriate nation...

My copy is being sent!

In the land of the binary, long ago, Where circuits glowed and screens were slow, A new age of computing had begun, Machines on desks, small but fun. The geeks of the world did gather 'round, To hear the clicking beeps of these machines' sound. The games were simple, but still we played, On screens ...

The ZX80 vars are more compact and not very much free space to be used in basic start. Anyway in the kit there is the best solution I've found (if there are better I'm all ears :) ), surely more than enough for a loader program. And to be clear: the basic is to start, the rest should be machine code...

On a ZX81 I have placed the basic over the sysvar, need to check how it can be done on the ZX80. You can have a look at the 1K starter kit: https://sinclairzxworld.com/viewtopic.php?f=6&t=2349 It contains example program (for both machines), assembler, instructions and possibilty to debug with Visu...

Really a short one and filled with a lot of imagination in between I think. Anyway agree with machine code. Using a set of 32 characters I think you can save text to print in 5 bits per character compacting all text together and call a routine with initial char and end char parameters for printing. ...

Seems by chance that also specdrum was using A5!

The ZN428 is a Ferranti semiconductors product, and is quite old, so certainly existed in the 1980s. See the dates at the end of this data sheet . Of course, it would not have been cheap… Then we can design two absolutely compatible boards to choose from! :) Is bus signal A5 good to go (meaning the...

@Freya : is ZN428 is a nice chip, but is "era compatible"? Seems to me that is a product of the 90s more than the 80s... With the solution of MAK you should add really just a bunch of resistors and you can go with a single widespread 74hct377! More, with a simple DPDT switch in the middle of the R2R...

Oh, I think it’s possible to get even simpler if you don’t mind doing it the “dirty” way… :lol: A5 to /E (pin 1) on the 74xx377 /IORQ to CP (clock pulse)(pin 11) on the 74xx377 No other chips, diodes, or resistors (for the control lines) needed. Just ensure that the software does not try to input (...

Yes, this is what I was thinking about! Very nice music, and as usual Yerzmyey is an artist! 4 bits doesn't seem bad, one 377 may suffice even for the two stereo channels in case! The tracker can even be ported if there are the sources or there is the author around. In the meantime I had a new idea ...