Program in EPROM

[Markie_V]

Since a while I'm starting to play with my ZX81 again and I would like to restore some old projects I did a long time ago.

One of them was a 'plant watering system' I made in 1986 which should give my plants water when I was on military exercise.
This was based on a ZX81 with a homebrew I/O interface and some (washing machine) magnetic waterlocks...
It was one of the most highly!! none reliable systems I ever build, but I will not go to deep into that.

One of the biggest problems was to restart the system, the only thing to load the program again was the cassette player.
It would be so much easier if I could store the program in EPROM and auto start on reset.

The question is, is this possible?

I can imagine if I rewrite the whole program in assembler I can store this in EPROM and with the right reset vector it should
start after a reset.
Since speed is no issue I still could use the BASIC interpreter with the difference that the program is stored in EPROM and not
in RAM.

Any thoughts on this?

Grtzz Mark

PS: I know an Atmel 328p can do this with two fingers in it's nose, but where's the fun in that...

[XavSnap]

Hi Markie_V,

To Load a P file in ROM, and auto execute it:
Have a look to this tread: https://www.sinclairzxworld.com/viewtop ... f=7&t=5531

Only the MEMOTECH MEMOCALC & MEMOTEXT can patch to ZX81 ROM (using a PLA) to start an ASM program.
But, Wilf Rigter can do it with a simple ROM patch...
https://quix.us/timex/rigter/AutoBasic.html
You had to burn a new 8k ROM, to launch you code. (Or use a dedicated card to swap the ZX81 ROM, the Zxpand for example)

[1024MAK]

Given that you are going to be burning an EPROM anyway, the easiest way is to use a 16K byte (27128). Patch the BASIC part to jump to the ‘upper’ half, where you can have a short bit of code to copy your program into RAM and then set-up the BASIC system. Then jump to the main loop in the BASIC ROM with BASIC set to execute mode.

Mark

[Paul]

Try search for store demonstrator in this forum.
It does what you want

[XavSnap]

"store demonstrator":
https://www.sinclairzxworld.com/viewtop ... 092#p46092

PCB:
http://zx81.ordi5.free.fr/CartesZx81/Ti ... onstrator/

Just change ASM codes to call all offset @$2000 instead of @$4000, and a simple RUN launch it.
Your BASIC/ASM program will RUN with a 1K/2K ZX81/TS1000...