What else might be connected on the ZX81 alongside the ZXPand+ ?

Discussions about Sinclair ZX80 and ZX81 Hardware
FrancoisLanciault
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What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by FrancoisLanciault » Fri Aug 02, 2019 11:50 pm

Hi,

I have a ZXPand+ that works very well.

Now I was wondering what else can be attached to the ZX81 edge connector alongside the ZXPand+. I know that the ZXprinter can be attached and works ok.

Can the Westbridge 2050 modem works if the ZXPand+ is connected ? Maybe both share the same I/O or something and it won't work ?

What about my Memopack Centronics Printer IF ? If I remember well it modifies the ROM so the LPRINT and LLIST keywords would be re-directed to drive the centronics port... Problem with ZXPand+ ?

I know I could just try them out, but I don't want to fry anything.

Anybody knows?

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mrtinb
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Re: What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by mrtinb » Sat Aug 03, 2019 10:15 am

In this German thread you can find a PDF and maybe translate some of the conversation.

http://forum.tlienhard.com/phpBB3/viewt ... f=2&t=2327

It gives you a list of the I/O ports used by other devices and ZXpand. Any conflict won’t work.

There can also be conflicts in address space. No two devices can have RAM or ROM in the same space. So e.g. you mention a Centronics interface that replace some of the ROM area (0K-8K). Since the ZXpand replaces the whole ROM area, there’s a conflict, and they cannot work together.
Martin
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube

Moggy
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Re: What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by Moggy » Sat Aug 03, 2019 1:37 pm

mrtinb wrote:
Sat Aug 03, 2019 10:15 am
In this German thread you can find a PDF and maybe translate some of the conversation.

http://forum.tlienhard.com/phpBB3/viewt ... f=2&t=2327

It gives you a list of the I/O ports used by other devices and ZXpand. Any conflict won’t work.

There can also be conflicts in address space. No two devices can have RAM or ROM in the same space. So e.g. you mention a Centronics interface that replace some of the ROM area (0K-8K). Since the ZXpand replaces the whole ROM area, there’s a conflict, and they cannot work together.
Not quite correct in reference to the centronics interface, I have one of these and it does work if you switch the ZXpand overlay ROM out by using the "CONFIG X" command which unfortunately reduces the ZXpand to just a 32k RAM module.

I also use a Cheeta sweet talker speech unit with my Zxpands successfully as well as a Zonx-81 AY unit wired for stereo with the ZXpands AY port changed to produce a turbo sound unit.

FrancoisLanciault
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Re: What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by FrancoisLanciault » Mon Aug 05, 2019 10:43 pm

Thanks both of you.

I guess I will try and see what happens.

François

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mrtinb
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Re: What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by mrtinb » Wed Aug 07, 2019 8:01 pm

(Hi Moggy, I'll mini hijack the thread with a small question about the Memotech Centronics I/F: The manual shows how to send the ascii codes, and states that the apostrophe is made by sending an inverse apostrophe to the printer. This is an error in the manual, as we know, that the ZX81 does not have an apostrophe. Do you know which inverse character to send? http://www.zx81stuff.org.uk/zx81/hardwa ... .15.16.jpg)
Martin
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Moggy
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Re: What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by Moggy » Wed Aug 07, 2019 11:15 pm

Oddly enough the only manual I ever saw is one on a German site which doesn't include the ASCII codes shown in your link.

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

I only ever used the interface to print a few listings then gave up on it as it wouldn't print the Sinclair graphics chrs so it's not something I came across, but in answer to your question I'm fairly certain that it's a simple typing error in the manual and the chr you need is an inverse colon as it appears to be the only chr not used and also it follows the inverse £...$ in the Sinclair manual so maybe the same for the printer manual?

FrancoisLanciault
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Re: What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by FrancoisLanciault » Sat Aug 10, 2019 5:54 pm

Moggy wrote:
Sat Aug 03, 2019 1:37 pm

Not quite correct in reference to the centronics interface, I have one of these and it does work if you switch the ZXpand overlay ROM out by using the "CONFIG X" command which unfortunately reduces the ZXpand to just a 32k RAM module.

I also use a Cheeta sweet talker speech unit with my Zxpands successfully as well as a Zonx-81 AY unit wired for stereo with the ZXpands AY port changed to produce a turbo sound unit.
Hi Moggy,

Reading the Memotech centronics interface manual, I see that it uses address space at 10k up. Does that means I must set the zxpand+ to use the 16k-48k memory space with the CONFIG "M=H" option ?

Thank you

Moggy
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Re: What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by Moggy » Sat Aug 10, 2019 6:11 pm

I seem to remember that being correct although I have to say it was an issue one xpand with early firmware not a plus model so not sure if that makes a difference?

I have to say it was very hit and miss when used with the Xpand as was the Memotech hi res unit which was very intermittent,sometimes working sometimes not, and I was never sure if it was a bad edge connector or that it didn't like playing with the xpand.

EDIT.

I have just checked on a program I use that loads to that area of memory and it seems I set the Xpand to low memory before loading and running so the memory high setting could be in error you will have to check both settings. It is a long time since I used the printer interface and sadly no longer have a printer to check which setting to use.

FrancoisLanciault
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Re: What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by FrancoisLanciault » Sat Aug 10, 2019 6:28 pm

Moggy wrote:
Sat Aug 10, 2019 6:11 pm
I seem to remember that being correct although I have to say it was an issue one xpand with early firmware not a plus model so not sure if that makes a difference?

I have to say it was very hit and miss when used with the Xpand as was the Memotech hi res unit which was very intermittent,sometimes working sometimes not, and I was never sure if it was a bad edge connector or that it didn't like playing with the xpand.

EDIT.

I have just checked on a program I use that loads to that area of memory and it seems I set the Xpand to low memory before loading and running so the memory high setting could be in error you will have to check both settings. It is a long time since I used the printer interface and sadly no longer have a printer to check which setting to use.
I can try both memory configuration and report. My only concern is that I don't want to damage either interfaces. But if you think there is no risk then I will check. I don't have the memotech Hires unit so it is going to be an experiment with zxpand+ and centronics interface only.

François

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Re: What else might be connected on the ZX81 alongside the ZXPand+ ?

Post by Bean » Thu Aug 22, 2019 1:45 am

I am having a problem using the ZXPand "Version 2.5 Dragon" with my ZXGame interface.

My interface uses the 8K to 16K area, but the ZXPand interferes with it even after I do CONFIG "M=H" and a CONFIG "M" show it as 16K - 48K. But if I poke the 8K to 16K region it will return what I poked. So it is acting like there is still RAM there. It does this even without my interface connected.

Am I doing something wrong ???

Bean

I did some more experimenting, there is no RAM from 40-48K even after CONFIG "M=H". Also after power off CONFIG "M" show 8-40K again.
It seems like the CONFIG "M=H" command is not working properly.
Might this be because it has the "DRAGON" firmware ?

Bean

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