Memotext & word processing in general

Discussion about ZX80 / ZX81 Software
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siggi
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Re: Memotext & word processing in general

Post by siggi » Thu Oct 05, 2017 3:27 pm

According to the manual

http://www.zx81.de/memotech/_frame_e.htm

MEMOTEXT takes over control of the ZX81 after startup until power off:
memotech wrote: STARTING UP

When you first plug in MEMOTEXT and switch
on the power to your computer, the first
prompt will ask you if you are using the
Centronics or the RS232 Interface. In common
with all prompts where you are asted to make
a simple choice between alternatives, you
should reply by typing the first letter of
the alternative you require. If you are
operating with a Centronics Interface you
should reply "C", and with our RS232
Interface you should reply "R".
and
Arrive at work; switch on MEMOTEXT; load a file of normal letters; load a
data file containing names & addresses of clients.
From time to time during the day go to MEMOTEXT; tell it which standard
letter you want; if it is for an existing client scan through the data file
for his details; if it is for a new client select the I option for data file
printing and be prompted for the information needed by the standard letter.

At the end of the day switch off MEMOTEXT and go home.
So I don't think, that it is possible to read/copy the memotext rom while connected to a ZX81. I think, the only solution is to read the roms in an eprom burner, store its content in a file and try to disassemble the code to find out, at which address the code expects to be run.

If that is possible, the rom content (and the original ZX81 rom content in the gaps between the memotext roms) could be "loaded" to flash "rom" (at the same address) of a ZxMore instance >= 1
If the code there could be run starting at address 0 (Karl?), this instance maybe will behave like a ZX81 with memotext rom installed

Siggi
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1024MAK
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Re: Memotext & word processing in general

Post by 1024MAK » Thu Oct 05, 2017 4:14 pm

It could be that is simply a single ROM chip that is used, replacing the 8k byte BASIC ROM. If so, the start address will likely be 0x0000 so that the CPU executes it at power on.

Mark

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mrtinb
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Re: Memotext & word processing in general

Post by mrtinb » Thu Oct 05, 2017 4:33 pm

Strange that Memotext can't be disabled, so to use another program you have to pull it out. That's not very userfriendly or hardwarefriendly.
Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

Moggy
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Re: Memotext & word processing in general

Post by Moggy » Thu Oct 05, 2017 4:40 pm

1024MAK wrote:
Thu Oct 05, 2017 4:14 pm
It could be that is simply a single ROM chip that is used, replacing the 8k byte BASIC ROM. If so, the start address will likely be 0x0000 so that the CPU executes it at power on.

Mark
I ask in all ignorance and wanting to learn, how does either the 4k 2732 or 2k 2716 inside the unit replace the 8k zeddy ROM?
Does it boot up from either one of them then hand back to the zeddy ROM to handle its housekeeping duties etc?
If so how does the zeddy ROM hand back control to the module?

As for entry points the conflict I mentioned in my earlier post is mentioned in the the manual I have for the Z80 assembler module, so perhaps can shed some light on this.

" Note however that the ASSEMBLER EPROM
resides between 12K and 16K and therefore cannot be used simultaneously with
the MEMOTEXT Word Processor or the MEMOCALC Spreadsheet Analysis Pack which
also occupy the same area. These three software packs can be fitted together
physically on the same system, but only one should be switched on (at the
side) at a time."


@Martin.

As mentioned in my earlier post the unit has a physical switch on the side to disable it.

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siggi
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Re: Memotext & word processing in general

Post by siggi » Thu Oct 05, 2017 4:51 pm

Moggy wrote:
Thu Oct 05, 2017 4:40 pm
1024MAK wrote:
Thu Oct 05, 2017 4:14 pm
It could be that is simply a single ROM chip that is used, replacing the 8k byte BASIC ROM. If so, the start address will likely be 0x0000 so that the CPU executes it at power on.

Mark
I ask in all ignorance and wanting to learn, how does either the 4k 2732 or 2k 2716 inside the unit replace the 8k zeddy ROM?
Does it boot up from either one of them then hand back to the zeddy ROM to handle its housekeeping duties etc?
If so how does the zeddy ROM hand back control to the module?

As for entry points the conflict I mentioned in my earlier post is mentioned in the the manual I have for the Z80 assembler module, so perhaps can shed some light on this.

" Note however that the ASSEMBLER EPROM
resides between 12K and 16K and therefore cannot be used simultaneously with
the MEMOTEXT Word Processor or the MEMOCALC Spreadsheet Analysis Pack which
also occupy the same area. These three software packs can be fitted together
physically on the same system, but only one should be switched on (at the
side) at a time."
So I think, that the 4K rom is located at 12-16K and the 2K rom is mapped to address 0 to replace the first part of the basic rom. Then the Z80 starts in the 2K memotext rom (at address 0), while (if address decoding is well done, and I think the MEMOTECH people know how to do) the remaining part of the BASIC rom (address 2K-8K) is still there and it's routines there can be re-used by the MEMOTEXT rom.

Siggi
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Moggy
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Re: Memotext & word processing in general

Post by Moggy » Thu Oct 05, 2017 4:58 pm

Thanks for that Siggi that makes sense to me now.

As for the EPROM contents If they were socketed and not soldered I would happily remove them and get the code.

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Re: Memotext & word processing in general

Post by mrtinb » Thu Oct 05, 2017 5:04 pm

The 4K ROM must be between $3000 and $4000 as Memocalc documentation says:
MEMOCALC is addressed between 12 and 16K. You can either switch on your MEMOCALC by hand (at the side of the pack) to jump straight in, or make a USR call at 13824 (eg RAND USR 138324) after you have powered up.
Assuming Memocalc and Memotext uses same setup.
Martin
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Moggy
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Re: Memotext & word processing in general

Post by Moggy » Thu Oct 05, 2017 5:12 pm

I no longer have the Memocalc but remember it having just the one 2732 EPROM.

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siggi
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Re: Memotext & word processing in general

Post by siggi » Thu Oct 05, 2017 5:17 pm

Yes, Memocalc runs in 8-16K region and does not have a boot-rom at 0 (thus must be started from BASIC).
I once played around with the memocalc image, running in ram at 8K and replaced the LOAD/SAVE routines to use MEFISDOS and MMC card for storage :mrgreen:

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1024MAK
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Re: Memotext & word processing in general

Post by 1024MAK » Thu Oct 05, 2017 6:44 pm

Moggy wrote:
Thu Oct 05, 2017 4:40 pm
1024MAK wrote:
Thu Oct 05, 2017 4:14 pm
It could be that is simply a single ROM chip that is used, replacing the 8k byte BASIC ROM. If so, the start address will likely be 0x0000 so that the CPU executes it at power on.

Mark
I ask in all ignorance and wanting to learn, how does either the 4k 2732 or 2k 2716 inside the unit replace the 8k zeddy ROM?
Does it boot up from either one of them then hand back to the zeddy ROM to handle its housekeeping duties etc?
If so how does the zeddy ROM hand back control to the module?
Sorry, in a rush to finish my post as the train approached the station I was getting off at, I appear to have made a bit of a mess of it :oops:

Thankfully Siggi has cleared a way through the fog... :D

Mark

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