QL ROM switcher

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tetroid
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QL ROM switcher

Postby tetroid » Sun Sep 24, 2017 11:26 pm

I seen Minerva ROM based on standard 27C512 ROM and I think is not easy to install on standard QL ROM socket, bacause of its big physical size. I am try to make more flat ROM replacement.


Image

Image

Image


This ROM switcher has 512Kb ROM , that allows to have 8 ROM images.
Does anybody advise what ROMs most popular / important?
And next question about copyright for this ROMs, what ROMs can I use ?

http://www.dilwyn.me.uk/qlrom/index.html

ROM switcher has 4-position switch, 3 swithes for select the ROM image.
Last ( 4 ) switch adds ROM area C000 - FFFF ( for example Toolkit 2 ), ON - adds, OFF - w/o using C000-FFFF.


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vanpeebles
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Re: QL ROM switcher

Postby vanpeebles » Mon Sep 25, 2017 8:00 am

That looks great! Would it be possible to have the switches on the end of a long cable? (To save opening the QL)


tetroid
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Re: QL ROM switcher

Postby tetroid » Mon Sep 25, 2017 2:14 pm

vanpeebles wrote:That looks great! Would it be possible to have the switches on the end of a long cable? (To save opening the QL)


Thank you , good idea.
It is only necessary to find a place on the case, where to mount this switch.


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tofro
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Re: QL ROM switcher

Postby tofro » Mon Sep 25, 2017 2:48 pm

To my knowledge, you can use any of the ROM's available from Dilwyn's site, with one general exception:

The copyright of the original ROMS made by Sinclair themselves somehow ended up at two different places - Amstrad, who have made the ROMs freely available and distributable, and some party in the US who didn't - for their region, at least (I think Dilwyn's page has some details and a contact address for them). That leads to two different copyright situations for ROMs distributed into the US and everywhere else. (Applies to versions AJ, JM, JS, MG and patched derivates).

Minerva has been made freely distributable by its Author Lau Reeves.

Another problem is that the ROM needs to fit the hardware (mainly the keyboard layout, and maybe the ROM messages). Only Minerva is switchable between layouts, the unpatched version will need to load the non-UK keyboard layouts into RAM using a binary driver. ROMs of Sinclair origin had a fixed keyboard layout built-in (MG), and were distributed in different versions for various countries. There is no way to have a JS ROM use the Italian keyboard layout, for example, without directly patching it.

So, unfortunately, you will probably need to provide different language versions for different keyboard layouts:

AH, JM, JS, MGUK, Minerva (a patched version of MG for the UK keyboard layout) makes sense in one batch for UK QLs

For non-UK keyboards, without patching only MG (per country) plus Minerva makes some sense if you don't want to end up with a keyboard that produces the wrong characters.

Generally, there is not a lot of reason why somebody would want to use something older than JS on a UK and something older than MG on a non-UK QL. Minerva is always worth using, in my opinion.

As an add-on ROM, TK2 is definitly the ROM of choice.

I see you have used a Flash ROM device - Is it possible to reprogram it without soldering?

Tobias


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janbredenbeek
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Re: QL ROM switcher

Postby janbredenbeek » Mon Sep 25, 2017 3:11 pm

tofro wrote:Generally, there is not a lot of reason why somebody would want to use something older than JS on a UK and something older than MG on a non-UK QL. Minerva is always worth using, in my opinion.

I wonder if there are images around of FB and PM ROMs, just for fun? :D
Somewhere in the autumn of 1984 I got my hands on one of the first QLs in Holland (probably not officially imported; general availability here started afaik in early 1985), in a local computer store. It was one of the early QLs with a dongle and FB ROM. The editor did not let you edit a 'bad line', you had to enter it again entirely. And it didn't take long for the 'bad or changed medium' message to pop up when loading Quill... So I decided to wait a little longer before buying a QL (but just not long enough for the price drop :cry: ). But if I had bought this QL, I'm sure it would be a collector's item now...

Jan.


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tofro
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Re: QL ROM switcher

Postby tofro » Mon Sep 25, 2017 3:45 pm

Not sure if anyone found it even worthy to preserve "F"aulty "B"ugs - It probably won't fit into Tetroid's 48k anyhow.

My first QL (unfortunately also bought for the highest possible price in 1985) already had an MG ROM, which still is IMHO the most usable original QL ROM - When prices dropped to low bottom, I bought another one, just for spares. I still have both and never really needed to scavenge the latter, fortunately....

Only much later I obtained a JM version from the UK, which started to annoy me soon, so it was upgraded to JS and later to Minerva (Original ROMs are still somewhere in a drawer, never to be looked at since).

Tobias


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Re: QL ROM switcher

Postby Nasta » Mon Sep 25, 2017 3:52 pm

Sadly, no...
On the QL the ROMOEH line that selects the ROM is only generated for read cycles, and writes are necessary for programming the Flash chip in-circuit.
Even worse, if a GC or SGC is used, the board does not even generate write cycles on the bus when addressing these addresses :(


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tofro
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Re: QL ROM switcher

Postby tofro » Mon Sep 25, 2017 4:10 pm

Nasta wrote:Sadly, no...
On the QL the ROMOEH line that selects the ROM is only generated for read cycles, and writes are necessary for programming the Flash chip in-circuit.
Even worse, if a GC or SGC is used, the board does not even generate write cycles on the bus when addressing these addresses :(


I maybe mis-formed my question: Can the ROM be programmed in an external programmer (all address lines and control lines accessible from a header). I wasn't actually asking that much ;)

Tobias


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Re: QL ROM switcher

Postby Dave » Mon Sep 25, 2017 5:11 pm

It should be noted that Paul Holmgren's contract with Sinclair Research died when Sinclair Research died. It is legally unenforceable.

That said, he's a super nice guy, and his "license fee" is if you use QDOS in new hardware, just give him one.

I don't ever plan to use QDOS in any hardware, so it doesn't affect me either way. Minerva is compatible and far better, and even then it is in many cases used as a boot loader for SMSQ/E.

Cool product, Tetroid. Makes my few hundred Minerva ROMs worth a bit less, but I was going to pretty much throw one in with everything anyway just to get more people using Minerva.


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dilwyn
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Re: QL ROM switcher

Postby dilwyn » Mon Sep 25, 2017 6:42 pm

This is a good idea for a project, tetroid.

I would suggest including these versions:
JM ( fairly common in UK, useful for testing software, fairly similar to AH)
JS (most common uk rom)
MG - some of the most widely used national variants such as French/German), note that MGUK is a private non Sinclair version and may need permission from John Alexander to be used)
A few versions of Minerva
Tyche rom (although i can't remember if it would fit in QL ROM space and how compatible with BBQL)


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