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BigEd
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Another joiner

Post by BigEd » Sun Jan 24, 2010 2:19 pm

Aha!

I bought a Beeb around the end of 1982 I think, having previously had a Compukit.

Been lurking on the BBC-Micro mailing list for a while, and you'll also find me on 6502.org

Presently working on a 65816 card which plugs into a 6502 socket - just today has been seen working in a Beeb at 12.5MHz and my co-conspirator is about to benchmark BASIC on it. It doesn't seem to work in an Oric, but that should be fixable.

Anyone else remember the GREEN GLOOP GULPER ?

Cheers
Ed

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MartinB
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Re: Another joiner

Post by MartinB » Sun Jan 24, 2010 3:24 pm

Hi and welcome Ed :D

The board sounds great! When do we get piccies and info...? =P~

Martin

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BigEd
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Re: Another joiner

Post by BigEd » Sun Jan 24, 2010 3:43 pm

MartinB wrote:Hi and welcome Ed :D
Thanks!
MartinB wrote:The board sounds great! When do we get piccies and info...?
We've got a project website and a gallery

Any ideas or suggestions about the project (or the website) are welcome.

I'm usually a week or so behind on posting our latest discovery or achievement

Cheers
Ed

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Re: Another joiner

Post by sorvad » Sun Jan 24, 2010 7:57 pm

Welcome and seriously interesting project there :)

I've only had a quick shuftie at the site so apologies if I;m asking something that's answered on there, but where would be the main bottleneck on the Beeb when ramping up the CPU clock speed. Where is the limit with regards the rest of the system ?

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BigEd
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Re: Another joiner

Post by BigEd » Sun Jan 24, 2010 8:16 pm

The way we've tackled it, the CPU runs at high speed only when executing code from the fast memory we have on board: any access to the motherboard has to slow down to 2MHz or even 1MHz. Because the slow clock is free-running, there's no point in speeding up for one or two cycles.

So what we've done is remapped some or all of the host's 32k RAM, and some or all of the ROM, into the fast memory on board.

At present we have the BASIC ROM mapped, but not the OS. We have the bottom 16k of RAM mapped, and the upper 16k of RAM is mapped but we slow down on writes, to write to both the host RAM and the fast RAM. So, for most video modes, the printing and graphics comes out fine, but we slow down a bit both for those writes and in running the VDU drivers from OS ROM.

For BASIC benchmarks that just do computation, we can run at 12.5MHz and get a 6x speedup on the original. I hope to do a line-drawing intensive benchmark soon.

We haven't done anything to help disk access (or tape access!)

Cheers
Ed

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sorvad
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Re: Another joiner

Post by sorvad » Sun Jan 24, 2010 8:28 pm

Aha, I thought you might be having on -board rom/ram. Nice work. Should improve most stuff nicely. It's an interesting project and I'll have a more in-depth look at the site when I've got more time and not got my "tired" head on.

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Re: Another joiner

Post by sorvad » Sun Jan 24, 2010 8:35 pm

Sorry I'm going a little off topic here for these forums but have you any theories yet (or possibly you've not had time to think about it) about what the Oric's problem is ? I;m trying to remember the hardware details of the Oric, but like our little Electron I think it had a ULA that did a lot of the work for video/ memory decoding etc.

Actually back on topic... Have you no Elks to try it on ? If not you might be able to get some donated ? They used to go for about £5 on eBay until the change in seller rules which reduced the number on there :(

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Re: Another joiner

Post by BigEd » Sun Jan 24, 2010 9:15 pm

The Oric's a very interesting design, but we're stumped for now. We do have an Elk - in both cases the CPU is soldered rather than socketed, which is a disincentive.

I'm not sure how our latest scheme would be expected to work in Electron. I've just had the briefest look at the circuit and it isn't ruled out - it seems to use a stretched clock rather than the RDY input.

There are many ways for us to go forward, but we might at least have a look and a think for all the machines we've got: even the Dragon might be interesting and that's not even 6502.

On the other hand, we might well divert ourselves into TUBE-connected coprocessing next. Anyone for a 65816 co-processor?

Cheers
Ed

Edit: fix typo

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sorvad
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Re: Another joiner

Post by sorvad » Sun Jan 24, 2010 9:32 pm

BigEd wrote:On the other hand, we might well divert ourselves into TUBE-connected coprocessing next. Anyone for a 65816 co-processor?
Have you looked at Jon Kortinks work in this area, this supports 65816 processor;

http://web.inter.nl.net/users/J.Kortink ... 2/what.htm

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Re: Another joiner

Post by Greybeard » Sun Jan 24, 2010 9:43 pm

Welcome Mr.Ed! :)

I've just had a quick look at your sites. Very interesting (I shall need to come back and spend a bit more time on them).

But ... one quick thought. Was the Atmos Oric's contender for the BBC contract, I wonder?

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Re: Another joiner

Post by BigEd » Sun Jan 24, 2010 9:53 pm

sorvad wrote:
BigEd wrote:... TUBE-connected coprocessing ... a 65816 co-processor?
Have you looked at Jon Kortinks work in this area, this supports 65816 processor
Yes, I've seen his Reco6502 but I hadn't registered that it supports 65816 (which is natural enough as it's very compatible by design.)

It would be interesting to know how popular the 65816 option is.

We're doing all this for our own interest, so it's not that crucial if something's been done before. I'd quite like to be able to TUBE without a TUBE ULA, but it's a bit tricky. Our first effort is likely to use an original ULA.
Greybeard wrote:Was the Atmos Oric's contender for the BBC contract, I wonder?
I think they were a bit late to the party.

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Re: Another joiner

Post by retroclinic » Sun Jan 24, 2010 10:02 pm

Hi.

Welcome on board! That project looks good =D> - it's actually almost identical to one I had pencil'd in as an idea to try this year, but as you're doing it I'll give it a miss, I've got plenty of other things to be getting on with.

Mark.
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Re: Another joiner

Post by retro_junkie » Mon Jan 25, 2010 12:17 am

BigEd wrote:We do have an Elk - in both cases the CPU is soldered rather than socketed, which is a disincentive.
Are there early ones with socketed CPUs? If so I'll keep a look out and let you know. I've only ever seen soldered ones though. I've got an issue 2 board with socketed OS/BASIC (IC2) if that helps (or if it's of use to anyone else...)!

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Re: Another joiner

Post by sorvad » Mon Jan 25, 2010 8:18 am

GreyBeard wrote: Was the Atmos Oric's contender for the BBC contract, I wonder?
I think they were a bit late to the party.
In "The Micro Men" it was mentioned as a contender... But of course Tangerine systems at that point may have just had a name "Oric" and really not even a design and just threw their cap in as it seemed a good idea. Other option is Micro Men researchers got this bit wrong. Which I think more likely as I'd never heard of Tangerine putting there cap in the ring and can't find any thing on the web mentioning it (well not on Wikipedia's Tangerine entry anyway !)

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Re: Another joiner

Post by AndyF » Mon Jan 25, 2010 10:04 am

Hello and welcome :)
Andy

* NEW * The Jetset Willy and Manic Miner community :)

Adventure games ported across to the BBC (in progress) as soon as I can find some time!

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Re: Another joiner

Post by BigEd » Mon Jan 25, 2010 6:40 pm

retroclinic wrote:Hi.

Welcome on board! That project looks good =D> - it's actually almost identical to one I had pencil'd in as an idea to try this year, but as you're doing it I'll give it a miss, I've got plenty of other things to be getting on with.

Mark.
Hi Mark
thanks! That's interesting. I've had a quick look at your products - nice! We've the idea of making our work freely re-usable, rather than trying to sell anything ourselves. It's likely that it would need some productisation anyway. Oh, and we're using the free version of EagleCAD which precludes profit.

Cheers
Ed

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Re: Another joiner

Post by BigEd » Mon Jan 25, 2010 6:45 pm

AndyF wrote:Hello and welcome :)
Cheers!

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Re: Another joiner

Post by retroclinic » Mon Jan 25, 2010 6:50 pm

Hi.

I've had to regsiter my version of Eagle for profit use, but only for the lowest size PCB - you need a flipping mortgage to produce the bigger boards with that software!

On the ULA side, I started to make some notes, and you should be able to get it into an XC95108 or 144 at worst, but you'd need to use an external FIFO RAM, even a small one like IDT7201LA35JG 512x9 (they don't seem to do x8 for some reason) would add about £3 per board (in 100 qty), and may even itself give a performance boost because of the larger amount of memory available to it. I've gone no further with it due to keep getting distracted with other things.

Mark.
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Re: Another joiner

Post by BigEd » Mon Jan 25, 2010 7:12 pm

retro_junkie wrote:Are there early [Elks] with socketed CPUs? If so I'll keep a look out and let you know. I've only ever seen soldered ones though. I've got an issue 2 board with socketed OS/BASIC (IC2) if that helps (or if it's of use to anyone else...)!
If I had an Electron with a socketed (or unwanted!) CPU in it, I'd certainly give it a go.

As for socketed ROMs, I have a wild idea for putting a 60MHz 6502 on an FPGA into such a ROM socket, as a TUBE-in-ROM if you like. We have a suitable 24/28pin FPGA module, so it's not impossible we'll try this one day.

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Re: Another joiner

Post by BigEd » Mon Jan 25, 2010 7:37 pm

retroclinic wrote:On the [TUBE] ULA side, ... you should be able to get it into an XC95108 or 144 at worst, but you'd need to use an external FIFO RAM...
We happen to have two 95108 and a (faster but smaller) 9572, both in 84-pin. I'm minded to first try for something with shallower buffers - elsewhere on the forum regregex is hopeful:
regregex wrote:A Tube ULA with shallow FIFOs would presumably work...
We did have a think about external FIFOs - I think possibly the extra pin count was an issue, but possibly at that time we were looking at 44-pin CPLDs. Another idea was to use the TUBE-side RAM as FIFO - stalling the processor and doing DMA.

Cheers
Ed

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Re: Another joiner

Post by darren.au » Mon Jun 14, 2010 12:04 am

Hi Ed,

I remember the Green Gloop Gulper. It was the first listing I ever typed in from the Micro User mag. It was the first time I ever used a BBC micro (or any real computer for that matter). It look me months to type in the game and debug it. I only had 20mins a day after school. As a learner I encountered lots of set backs, eg. not being aware I have to SAVE the game when I finished typing etc.

I was so happy when I got it going, but it was a bit hard to play.

Darren.
Brrrrrrr-beep

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Re: Another joiner

Post by iomanoid » Mon Jun 14, 2010 12:58 am

darren.au wrote:As a learner I encountered lots of set backs, eg. not being aware I have to SAVE the game when I finished typing etc.
Haha :lol:
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Re: Another joiner

Post by BigEd » Mon Jun 14, 2010 9:22 am

darren.au wrote:Hi Ed,
I remember the Green Gloop Gulper.
Darren.
Hurrah!

After some obsessing last December, I rediscovered a copy of the game which I'd previously found online in disk 8 of the telesoftware archives:

Code: Select all

"THE CITY IS BEING INVADED BY THE"'T$"DREADED CREEPING MUTANT GREEN
GLOOP."^M^G<D0>}<F1>T$"IT'S UP TO YOU TO SAVE IT BY GULPING"'T$"THE
GLOOP WITH YOUR TRUSTY GLOOP"'T$"GUZZLER BEFORE THE GLOOP GULPS YOU !"
and indeed I spun it up in an emulator shortly afterwards - bit of trouble with keypresses being dropped or doubled. (I've attached the BASIC)
darren.au wrote:I was so happy when I got it going, but it was a bit hard to play.
I've got a vague recollection that a friend and I made a small change so it would be more pacman-like: store a keypress until the next junction was reached. That helped the playability.
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GLOOP.zip
GLOOP game as text file (c) The Micro User
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