Mega Games Cartridge for the Electron MGC

reminisce about bbc micro & electron games like chuckie egg, repton, elite & exile

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JonC
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Re: Mega Games Cartridge for the Electron

Postby JonC » Mon Feb 20, 2017 8:05 pm

davidb wrote:....DaveH and I discussed loading and saving for games that support it, and the question arises: which filing system would you like to see supported?


Good question! Maybe default to the FS rom in a certain slot/position? That way people could select there own.

Interestingly, the tape relay clicks when I try to load an Elite commander, so tape is still an option, if a slow one! :lol:
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daveejhitchins
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Re: Mega Games Cartridge for the Electron

Postby daveejhitchins » Tue Feb 21, 2017 7:31 am

Hmmmm! Could we: Take over a small area of memory (the difficult bit) that intercepts calls that want to save/load - switches in a predefined bank of the FlashRAM that would hold all the code we need to do this with . . . Now I know the the answer is going to be no, however, I always say "don't say no" say "I can't think of a way, at the moment" - and then let's ponder on this matter. At some point I'll need to make another batch of MGCs - an ideal opportunity for a redesign (needs to be Master compatible too, this time) - Good for sales too e.g. all the latest features that people will just have to have :lol:

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
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JonC
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Re: Mega Games Cartridge for the Electron

Postby JonC » Tue Feb 21, 2017 9:33 am

Or...
Since save games are usually fairly small files, is their some cheap, fast, simple hardware that we could plug into the tape port that would allow us to save/load at max speed?
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paulb
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Re: Mega Games Cartridge for the Electron

Postby paulb » Tue Feb 21, 2017 11:06 am

JonC wrote:Or...
Since save games are usually fairly small files, is their some cheap, fast, simple hardware that we could plug into the tape port that would allow us to save/load at max speed?


The tape port is pretty much limited to 1200 baud data encoded as analogue audio. You can obviously use another device to play and record such data, and it could be a fun project to make a dedicated one with analogue-to-digital and digital-to-analogue converters plus storage under "motor control", but I doubt you could make it any faster than tape always was.

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davidb
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Re: Mega Games Cartridge for the Electron

Postby davidb » Tue Feb 21, 2017 11:28 am

daveejhitchins wrote:Hmmmm! Could we: Take over a small area of memory (the difficult bit) that intercepts calls that want to save/load - switches in a predefined bank of the FlashRAM that would hold all the code we need to do this with . . . Now I know the the answer is going to be no, however, I always say "don't say no" say "I can't think of a way, at the moment" - and then let's ponder on this matter. At some point I'll need to make another batch of MGCs - an ideal opportunity for a redesign (needs to be Master compatible too, this time) - Good for sales too e.g. all the latest features that people will just have to have :lol:

Just as a game finishes loading, we could switch to two separate ROMs. The first would contain code to handle loading and saving, perhaps using the ROMFS, though that doesn't support saving (as far as I know) so maybe a different filing system would need to be used. The second would initially be "blank" and could be used for saved games.

If you used ROMFS for this, the first ROM would need to be able to encode ROMFS data and flash it to the second ROM in the correct place. Since ROMFS data ends with a &2B marker, I imagine it might be possible to update it to be &2A and extend the data. Loading would just work because the second ROM would become normal ROMFS storage. Erasing the ROM might be unreliable, however. The code to perform the writing would have to be (temporarily) located in RAM because the first ROM will be paged out so that we can access the second ROM. Maybe it would be possible to just use one ROM if the saving code was small enough.

Using a custom filing system might be better but, as I've never written one of those, I don't know how much work it would be.

This would only work for games that are completely in RAM and don't need to load more parts after the user has loaded or saved their own files.

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daveejhitchins
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Re: Mega Games Cartridge for the Electron

Postby daveejhitchins » Tue Feb 28, 2017 9:43 pm

Attached is a small BASIC program to SAVE MartinB's MGC Utilities that can be found in delivered MGCs. All future MGCs will ship with this program loaded. The program is based on the same program that shipped with the ABR - modified to save the MGC Utilities. You are offered the option to save to Tape, DFS and ADFS. The program can easily be modified to save to other filing systems. If you have one in mind let me know, with details, and I'll add it to the Program.

Dave H :D

Save MGC Utilities.ssd.zip
(1.2 KiB) Downloaded 23 times
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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daveejhitchins
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Re: Mega Games Cartridge for the Electron

Postby daveejhitchins » Tue Feb 28, 2017 10:04 pm

I need a Proof Reader for the MGC User Guide . . . Any volunteers?

Thanks - Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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MartinB
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Re: Mega Games Cartridge for the Electron

Postby MartinB » Tue Feb 28, 2017 10:15 pm

I'm laid up with a busted knee at the moment Dave so I'll be on the team if you like 8)

(Hence I can't get down to the Beeb vaults to progress my other MGC jobs for a few days at least.... :roll:)

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Re: Mega Games Cartridge for the Electron

Postby daveejhitchins » Wed Mar 01, 2017 8:30 am

Thanks Martin . . . I'll send it by eMail.

I wont ask about the knee - but how? Why? And when? :lol:

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
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Re: Mega Games Cartridge for the Electron

Postby MartinB » Wed Mar 01, 2017 7:29 pm

Monday afternoon at work, spontaneous Hemarthrosis in the right knee, rest of day in A&E - now bandaged, splinted and on crutches for a week or so :roll:

I have pictures of the emergency 'aspiration' but I think they're way too gross for a family forum... :lol:

Got the email ta, I'll have a read later 8)

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davidb
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Re: Mega Games Cartridge for the Electron

Postby davidb » Thu Mar 09, 2017 4:45 pm

Dave, did you get a chance to try the ROM I sent you? It's a proof of concept boot screen for the MGC.

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1024MAK
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Re: Mega Games Cartridge for the Electron

Postby 1024MAK » Thu Mar 09, 2017 5:51 pm

davidb wrote:Dave, did you get a chance to try the ROM I sent you? It's a proof of concept boot screen for the MGC.

That looks excellent =D> :D

Mark
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daveejhitchins
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Re: Mega Games Cartridge for the Electron

Postby daveejhitchins » Thu Mar 09, 2017 6:02 pm

davidb wrote:Dave, did you get a chance to try the ROM I sent you? It's a proof of concept boot screen for the MGC.
Ooooops! Forgot all about it :oops: Had a slight problem (my excuse and I'm sticking to it [-( ) in my workshop. Fitted some blinds and now I can't open the loft space hatch. So I'm having to plan major roof surgery as it's between two beams!

Back on subject . . . Looks brilliant! . . . I'll give it a go tomorrow and report back. And sorry again, I've just seen the date you sent it!!!

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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davidb
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Re: Mega Games Cartridge for the Electron

Postby davidb » Thu Mar 09, 2017 10:44 pm

Thanks guys. There's actually a bit of a difference between the way Elkulator and a real Electron run this demo. It looks even smoother on the real thing. :)

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Re: Mega Games Cartridge for the Electron

Postby AndyRCM » Tue Mar 14, 2017 8:33 am

Hello guys,
Are these still available? I would love one for the museum. :)

Andy
Andy Spencer
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http://www.retrocomputermuseum.co.uk

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fwibbler
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Re: Mega Games Cartridge for the Electron

Postby fwibbler » Tue Mar 14, 2017 7:37 pm

I hope so.
There are a lot of games not listed in the spreadsheet.
Im still hoping they will be added at some point before I buy mine.
Cheers

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davidb
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Re: Mega Games Cartridge for the Electron

Postby davidb » Tue Mar 14, 2017 10:07 pm

fwibbler wrote:There are a lot of games not listed in the spreadsheet.
Im still hoping they will be added at some point before I buy mine.

Which ones were you thinking of?

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Re: Mega Games Cartridge for the Electron

Postby daveejhitchins » Wed Mar 15, 2017 8:22 am

AndyRCM wrote:Are these still available? I would love one for the museum.
pm sent

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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Re: Mega Games Cartridge for the Electron

Postby daveejhitchins » Sat Mar 18, 2017 8:58 am

Just to advise that I've added the Draft MGC User Guide to the first post of this thread - I'll update it as I add to it.

Thenks - Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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fwibbler
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Re: Mega Games Cartridge for the Electron

Postby fwibbler » Sat Mar 18, 2017 11:58 am

davidb wrote:Which ones were you thinking of?


Im trying to build up a list, but its taking a while... :roll:

sadken
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Re: Mega Games Cartridge for the Electron

Postby sadken » Mon Mar 20, 2017 9:06 pm

Hi Dave,

I'm interested in getting a cart, finally picked up a Plus1 for my electron, and this would be an amazing addition ;)

Thanks

Andy

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Re: Mega Games Cartridge for the Electron

Postby daveejhitchins » Tue Mar 21, 2017 7:26 am

sadken wrote:I'm interested in getting a cart, finally picked up a Plus1 for my electron, and this would be an amazing addition ;)
Hi, Andy . . . Firstly, welcome to the Forum :D

Secondly, can you re-post this request, please, next week. On holiday, at the moment and I'll forget :shock:

Dave H :D

P.s. You could be looking at the Draft User Guide - which is on the first post of this thread!
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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Re: Mega Games Cartridge for the Electron

Postby Multiwizard » Tue Mar 21, 2017 5:42 pm

Yes,

today I received:

viewtopic.php?f=41&t=5594&p=164149#p164149


I have a little question... :oops:

I have connected a Plus1 and Plus3 to my Elk... :D

I did download the MGC User Guide 1V0.

And have tried this, see top pic.


Sadly it doesn't start the cartridge, but if I use one of these options it starts up the Elk normally or the floppy-drive of the Plus3 starts up...

Is there a kind of bypass so it won't go to the Plus3 floppy-drive?


Greetings, Wim... :-)

Thanks in advance...
Attachments
Break.JPG
P1190906.JPG

paulb
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Re: Mega Games Cartridge for the Electron

Postby paulb » Tue Mar 21, 2017 5:51 pm

Multiwizard wrote:Sadly it doesn't start the cartridge, but if I use one of these options it starts up the Elk normally or the floppy-drive of the Plus3 starts up...

Is there a kind of bypass so it won't go to the Plus3 floppy-drive?


Apparently, Shift-Space-Break selects ROMFS when booting.

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Multiwizard
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Re: Mega Games Cartridge for the Electron

Postby Multiwizard » Tue Mar 21, 2017 6:35 pm

paulb wrote:
Multiwizard wrote:Sadly it doesn't start the cartridge, but if I use one of these options it starts up the Elk normally or the floppy-drive of the Plus3 starts up...

Is there a kind of bypass so it won't go to the Plus3 floppy-drive?


Apparently, Shift-Space-Break selects ROMFS when booting.
Oh yes, it works,, beautiful... :D

Thanks Paul... \:D/


Greetings, Wim... :-)
Attachments
P1190909.JPG

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roland
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Re: Mega Games Cartridge for the Electron

Postby roland » Tue Mar 21, 2017 6:56 pm

You can also sell your Plus-3 to me :lol:
Looking forward to meet my MGC.....
256K + 6502 Inside
MAN WOMAN :shock:

sadken
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Re: Mega Games Cartridge for the Electron

Postby sadken » Tue Mar 21, 2017 9:20 pm

daveejhitchins wrote:Secondly, can you re-post this request, please, next week. On holiday, at the moment and I'll forget :shock:


No problem :D

In the mean time, have a great holiday ;)

Andy

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daveejhitchins
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Re: Mega Games Cartridge for the Electron

Postby daveejhitchins » Tue Mar 21, 2017 9:24 pm

Ah! Another entry for thr User Guide . . .

Thanks - Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

M Sadler
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Re: Mega Games Cartridge for the Electron

Postby M Sadler » Fri Mar 24, 2017 7:37 pm

Are these still available? I would love one for my growing Acorn Collection.

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davidb
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Re: Mega Games Cartridge for the Electron

Postby davidb » Fri Mar 24, 2017 8:18 pm

I believe so, though you'll have to wait for DaveH to return to find out for sure. I don't know how many boards and components he has left.


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