Electron Advanced User Guide

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jms2
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Electron Advanced User Guide

Post by jms2 » Sat May 24, 2008 3:49 am

As a result of having a small baby in the house I've been up in the early hours of the morning looking for something restful to do while trying to get her to sleep. As a result, I started going through the OCR'd version of the Electron Advanced User Guide that was on the web and managed to remove most, if not all, of the scanning errors (of which there were quite a lot).

I then noticed that there are a few things that I remember reading in Electron User that are not covered at all in this book, so I decided to create my own "second edition" with them included.

The changes relate to:

- FX calls which change when the Plus 1 is fitted
- Disabling the Plus 1
- Disabling the keyboard interrupt
- Reading the keyboard ROM

... all of which was found in EU articles.

Anyone have any other suggestions to include? I'm thinking of relatively minor additions rather than rewriting the whole thing or copying in chunks of other manuals, eg I see no need to duplicate the Plus 3 manual. One of the main factors in my mind when making the changes so far is not messing up the extensive index. This limits any changes to what can be squeezed into the existing white space. The other factor is of course time available to do it!

I can email the file and change log to anyone who is interested.

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Post by sorvad » Sat May 24, 2008 5:21 am

That is excellent. Once thing tht I remembeef from Elk User waas that they did a complete memory map brekdown over about 3 months. Don't think the Elk Adv. Guide covered it in as good a detail

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Post by jms2 » Sat May 24, 2008 7:20 am

Yes, thats one of the outstanding items that I have not yet included.

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Post by Fraser » Sat May 24, 2008 1:10 pm

I have them all scanned including one they forgot and printed in the letters pages later. Do you want them by email?

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Post by jms2 » Sat May 24, 2008 6:27 pm

Yes, that would be really useful. I had planned to download them from Acorn Electron World but if you have the exact articles all together already, it would help a lot.

I was hoping it might be possible to OCR them (and then edit the results).

The reason I've not done this already is the significant impact it would have on the index, so if anyone else can suggest any other inclusions that would be good.

I'll PM you with my address.

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Post by jms2 » Sun Jun 01, 2008 8:42 pm

I've decided to copy the memory map text from the BBC Advanced User Guide and amend it where necessary by reference to the Electron User article. There weren't many changes - so this saved me doing any OCRing.

I have a technical question for the list:

On p.125 (in the chapter about vectors), the EAUG says of KEYV: "On the Electron which doesn't use an interrupt driven keyboard, intercepting this call to the KEYV routine speeds up the machine enormously".

Now, what motivated me to improve the book in the first place was its complete omission of details of *FX178, which Electron User revealed switches off the keyboard interrupt - important on the Electron as it is such a slow machine. The above excerpt seems to allude to this, but it is phrased badly. The text implies (to me anyway) that the Electron design doesn't use interrupts to scan the keyboard - but surely it does, doesn't it?

I want to re-word this as: "If your program does not require the use of the keyboard, intercepting KEYV can speed up the machine enormously. Alternatively, switching off the keyboard interrupt will have the same effect, see OSBYTE 178."

Is this correct?

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Post by MartinB » Mon Jun 02, 2008 11:06 pm

Riding in a timely fashion on the back of this Electron knowledge thread......

I confess, it was me who bought the Electron ACP Plus 4 from eBay last week and to save amateur sleuthing, I am that f00landhism0ney! Anyway, after excitedly winning the auction, I spotted the 'Elk Mode 7 Adaptor' thread and read some err.., unsettling comments about my purchase so I decided to keep quiet until I'd got the thing and tried it :?

Well, it's here, it's like new, already fitted with the ADFS Rom (AP34?) and works perfectly! In fact, having shied away from my neglected Electrons over the years due to their Tape only impotence, I'm actually thoroughly impressed and delighted with ACP's gadget. (Although it's probably true to say I'm easily impressed by all new-to-me Beeb etc. gadgets.... :) )

The upshot of all this is that since I'm not at all familiar with the Elk but will now be 'having a play', I have some top-level questions which can probably be most quickly answered by the STH resident experts. I've had a quick flick through the Advanced User Guide (AUG) on the net but to save me scouring in more depth I thought I'd ask here. I don't need huge detail, just headline answers to a few technical questions.

1. Is Elk Sideways Rom code format the same as the Beeb's? I know the hardware addressing etc. is different but apart from that are the actual roms pretty much the same?

2. I notice Master Rom cartridges physically fit in the Plus 1 slots but are they electrically compatible? Why don't I see Elk cartridges around - are they pretty rare?

3. Is expansion hardware memory-mapped as per the Beeb? For example, if you add the Plus 1, does the ADC sit in specific memory locations just like the Beeb or is it all added through the 1Mhz bus as the AUG seems to suggest? Is this true of things like the Plus 4 too such that I couldn't just access the 1770 registers at several addresses?

4. Is the AUG the only definitive document for serious low-level tinkering? Sounds like it will be a lot better when John (jms2) has deluxed it up and will then perhaps answer all these irritating questions :lol:

5. Are there any good code monitors on rom (such as an Exmon II equivalent) for the Elk or would a non-Mode 7 Beeb monitor be compatible?

Just brief answers will do or if it's all been done before, as seems to be the case whenever I post :roll: , links to the best threads will be fine :)

Thanks, Martin

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Post by sorvad » Tue Jun 03, 2008 7:48 am

1. The ROM header information ( I think that's what your referring to) is the same across the Elk/Beeb/Master.

2. They are "sort of" electrically compatible. There are subtle differences, you could certainly design a cartridge that would work in both, and probably simple rom apps will work (if the software part is written legally). But for more advanced uses or even if the cartridge design assumes certain things then they are not going to be interchangeable. For more information see the Master Advanced Reference manual Part 1 (appendix 7) which describes the pins and the differences between the master and Elk versions of the interface. You don't see many cartridges for the Elk as the market was limited to users with a plus 1 and so not many were produced. You can usually pick up View and VeiwSheet etc. as Acorn produced sack loads of these. In fact I think I've got two View cartridges from back in the day (not sure how I ended up with two !)

3. All hardware expansion works just like the beeb in Memory mapped fashion. The 1Mhz bus behaves and is used in the same way as the beebs. The ADC certainly is memory mapped in the way you'd expect.

4. Errr... not sure, you'd think they'd be others... I would have thought some other hardware design book for the Elk would have been produced ? I've none in my collection anyway.

5. Don't know. Sorry.

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Post by CMcDougall » Tue Jun 03, 2008 8:46 am

MartinB wrote:2. I notice Master Rom cartridges physically fit in the Plus 1 slots but are they electrically compatible??
All 'blank/empty' master carts work on a elk with plus1, ive burnt lots of RFS games onto eproms, and ALL of them work 100% :D

ahh, so u won that ACP3 :twisted: :evil: :twisted: . Can you test Joe Blade 1&2, Exile & Repton3 for me, if they dont work, then :D :D :D 8)
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Post by MartinB » Tue Jun 03, 2008 12:17 pm

Thanks very much Steve, sounds like it's the usual DIY learning curve then and I'm sure I'll be back.... :?

Uh Oh Colin..... Two 'Twisted Evils' and a 'Very Mad' :shock: Thanks for the cartridge tip, I'll give it a go. I did plug one in but resisted switching on until someone gave me a warm feeling - which is better than a warm Eprom :)

I'll try those games and hopefully make your day when they fail! However, I'd still have bought the ACP even knowing that shortfall.... :wink:

Martin

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Post by MartinB » Tue Jun 03, 2008 9:48 pm

Here is the news you've been waiting for Colin :lol:

I pulled the ADFS rom before starting so the Plus 4 is just using the &E00 DFS and I took the disc images from STH so I presume they're good (?)

Exile - Loads and runs upto the point where it asks for words from the Novella which I don't have. During the load upto to this point there are some legible screens and I think two which look like the usual random data speckles on a Mode 0/1 screen.

Joe Blade 1 - Loading screens seem fine but then, I presume as the main game is about to run, blank screen and goes straight into a coma :(

Joe Blade 2 - As Joe Blade 1

Repton 3 - My saviour :D Loading screens/main menu all look good to me and on selecting 'Play' or 'Editor' everything works. Seems 100% ok

So, is this what you were expecting? I'll concede a 3-1 defeat if you'll lift the Evil Curse you cast on me :shock: although somehow, I don't feel cheated in the slightest because if I want to play these games I'll just use a Beeb and to be honest I'm more interested in the geeky side of things for which a disc drive is just essential. You see, my Electrons have suddenly been elevated from bleeping paperweights to real computers :wink:

I'll have a play with a Master cartridge in the Plus 1 now and see if I can get some roms to play ball although I just can't help feeling the trusty Logic Analyser is gonna see some Elk action. We shall see....

Martin

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Post by sorvad » Wed Jun 04, 2008 8:01 am

MartinB wrote: I'm more interested in the geeky side of things for which a disc drive is just essential. You see, my Electrons have suddenly been elevated from bleeping paperweights to real computers :wink:
That's just how I felt when I got my Plus 4 and disk drive connected up back in about 86. My Elk felt transformed from a plaything to a proper workstation. My coding on it from that point on exploded and I learnt 6502 on it. Something that I don't think could really have done with a cassette system very easily at all.

I didn't even want a Plus 3 as the plus 4 and 5.25 drive was the same as the Beebs set up and I'd always respected that machine so much (but could never afford one) that I wanted the same :)

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Post by CMcDougall » Wed Jun 04, 2008 8:18 am

MartinB wrote:images from STH so I presume they're good (?)
yip, all ok :D


Exile -it was this disc that should work http://www.stairwaytohell.com/electron/ ... xile_E.zip
no password etc, if it asks, just press Return :lol:

So i was right Martin, Joe Blade 1/2 is a no go on elk Disc, proberly the same as Tomcat and other Players games. I knew this would be a problem, as it took me a 'wee while' to get them to work on my beeb :D

Repton3, i meant, when you go play, main game comes up, then press L to load other screens, type $.FINALE (or whatever scr u wish), i get OSCLI OSCLI tape aborted :?
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Post by MartinB » Wed Jun 04, 2008 9:17 am

Colin - should have said - I did do just that and it was absolutely fine. I'm not that familiar with the game but figured from the file info that there were three scene overlays. Thus, I hopped repeatedly between Egypt, Prehist and Finale by just typing the name, no path character, and they all just loaded and worked.

That's the Exile image I used, I'll run it again, ignore the novella question and see if it runs.

Steve - obviously a kindred spirit. I now have a Beeb (or variants) and the Elk at the same workstation sharing a 3.5/5.25 combo through a Watford drive sharer and a Master in the wings. Acorn development heaven.... :D

Martin

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Post by MartinB » Wed Jun 04, 2008 9:35 pm

Tried Exile again and ignored the Novella question. The game certainly runs but the play-area border is scrambled and I'm not convinced the game scene is entirely as it should be :?

I'm not unduly surprised or concerned by any of this since even on the Beeb there are issues with games which will only work with certain DFS, some which enforce the 8271, some which hate Roms etc. etc. Even today, PC games and apps can be scuppered by Graphics cards, versions of Windows, anti-virus apps and so the story rolls on. How dull life would be without computer hardware & software compatibility issues...... :)

Anyway, to return this thread to it's rightful owner, just got a copy of John's cleaned, corrected and enhanced Electron Advanced User Guide and he's done a fantastic job :D It's a worthy replacement for the original and a must have for Elk owners - PM jms2 for a copy.

Martin

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Post by CMcDougall » Thu Jun 05, 2008 1:14 pm

^^ Exile should look like this : -

http://electrem.acornelectron.co.uk/ima ... image6.png

so looks like the 'new' hack works aswell :D

nice1 Bill Carr, and Martin for checking on his Plus4 :twisted:

jokin Martin, about the 'Twisted Evils' & 'Very Mad' mate :wink:
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Post by MartinB » Thu Jun 05, 2008 3:34 pm

Exile's ok then - that's exactly how it looks running from my Plus 4!

No worries Colin, I enjoyed the joke too :wink:. It's been fun and I needed an excuse to give the Plus 4 a good workout anyway. Also, since I've only just acquired an Elk disc capability, I needed to check that I could successfully convert disc images from the web to 'real' Electron discs. So all in all it's been fun and informative :)

Martin

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Post by Dave_E » Sat Jun 07, 2008 10:11 am

Have you tried the JOE BLADE disc images on Acorn Electron World? These were hacked by Mr. Spock some time ago. They certainly work fine on my AP4 Electron.

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Post by MartinB » Sat Jun 07, 2008 12:22 pm

No I haven't but I'll give them a try later and report back.

Thanks, Martin

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Post by MartinB » Sat Jun 07, 2008 8:43 pm

Well Dave, that was err.., interesting :?

I downloaded the images, made the discs, booted them on the Elk + AP4 and, as before, I got through all the menu stuff and loading screens but just as the game is about to run, blank screen and silence - forever. I tried versions 1 & 2 with the same result and even tried repeating the whole creation process but still the same :(

However, I was contemplating writing a suitable lamenting post when I thought I'd just have one more go. This time, on each disc, I first explored the Haven (?) menu screen viewing the instructions and the review and finally selecting the last scroll with a question mark which just bleeps and prints JOE BLADE on the screen. I then finally selected the Play symbol and, to my surprise, the games ran! Intrigued, I kept switching off and trying different permutations of selections and basically narrowed it down to my just having to select the mystery question mark scroll before running the game and all is well :D

Now, you're all probably going to tell me that this is known by everyone (except me) because it unlocks the protection or something.

Thoughts or knowledge anyone ? :?

Martin

( Still, the fact that they do run will have Colin McD as angry as a wasp again :x )

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Post by jms2 » Thu Jun 19, 2008 7:48 pm

OK - Issue 2 is now finished. I can email it to you but it is a 9MB PDF - for some reason the PDF file is bigger than the Word file and my attempts to shrink it have been unsuccessful.

Issue 2 contains some handy improvements and looks a lot nicer than the original.

I would be happy to accept suggestions for Issue 3.

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Post by jms2 » Sun Jun 22, 2008 8:33 pm

I now have the PDF down to less than 2MB, along with some further improvements to the book suggested by MartinB.

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Post by sorvad » Mon Jun 23, 2008 6:03 am

I can see me using this more than the paper version, which is not like me ! Really great work :)

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