Sinclair ZX80 / ZX81 / Z88 Forums

You talk with riddles, old wise guru.

What means, "the character will show on screen but not on tv " ?

First of all, I have my zx81 moded for composite and I use a contemporary monitor.

Is there a way to see characters on my contemporary monitor without the basic rom yes or no ?

What i want is just some characters on the screen without the usage of the main rom. After 40 years of development, none has ever created a game, a program, or even a text printed on the screen without the usage of the main rom. And if someone thinks "well there was no need for that", the answer is ...

Ok then let's start backwards. We could start deleting things from the original zx81 rom till we reach a point where we are left with only the absolute vital part with which we could print characters on the screen. That means, delete all the commands and just be able to print characters on the scree...

Hi I am looking for a program or game in assembly (I want the source code) for the zx81 that doesn't require the main zx81 rom to run. Which means, that one could either flash it on an EPROM at address 0 and it will automatically start when the machine initializes. Or, one could assemble the code, l...

Hi I believe there is the option to install a beeper on the zx81 and make sounds, right? You connect the beeper where? On the same port as the mic? Simple as that? With a little amplifier before the speaker? That is the same way of making sound with the eightyone emulator by enabling the "sound beep...

Paul I am in the extremely happy position to announce you that YOUR ROM WORKED! I successfully connected line A13 from the eprom to the bus and your rom WORKED like a charm! That is like a dream! FIREWORKS :lol: The VLA81 came yesterday. I honestly didn't expect your rom or my direct connection of ...

I just tried few experiments WITHOUT rem and it works, always.

This justifies my theory.

REM is not needed because we ALWAYS return to a safe memory location, since we were in basic prompt.

Could you talk to me like a programmer and not like a kid ? We are in BASIC prompt. And WE ARE in a safe location. The PC is set to that safe location. Let's say for the shake of our example that this safe location is 20000. So we are in basic prompt typing commands and we type: PRINT USR 25000 RET ...

I don't understand. the pokes would overwrite the content of line 10 What means "the pokes would overwrite the content of line 10" ? Line 10 is a poke. It enters the decimal number 62 into memory location 16514. What would have happened if I didn't use a rem statement? Which... I don't. As I underst...

Martin I didn't understand a bit of what you just wrote... but thank you anyway !

Is a REM statement needed in our case?