Mega Games Cartridge for the Electron MGC

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

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daveejhitchins
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Re: New Project, Super Games Cartridge

Postby daveejhitchins » Thu Nov 20, 2014 8:32 am

An update on the MGC project:

Bad news : Good news : Bad news : Good news!

Bad news: I don't know where I was when I did the first design (^above^) - What a load of poo! #-o I'd, somehow, got it in my head that a 4 to 10 decoder was required (should be a page latch driven from the data BUS) Doh! I realised as soon as I started to develop the PLD code. So, back to the drawing board!

Good news: After several attempts I finally managed to get all the functionality, I'd planned, into my 2 x GAL22V10s. Re-laidout the PCB and ordered a prototype - ordered the EEPROMS. Everything lined up for arriving today. PLD programming all done. ZIF SOP 44 to DIL test socket arrived (£6 from China :D ) - I test EVERY part from China. They replace any that fail.

Bad news: My EEPROM supplier informed me that the price of the AM29F032B, from their supplier, had increased in price by $3 :twisted:

Good news (and a bit of bad!): Shirley (made up name for my Chinese broker) has managed to find some parts at the original price - But! TSOP 40 instead of the easier to fit SOP 44. So, I have to re-layout the PCB (todays job) and have ordered a TSOP 48 ZIF to DIL test socket - £16 from china - so won't arrive just yet! It's a Wellon part that some people want to charge $178 for :shock:

Unfortunately I won't have any hardware for this weekend :? But, with the help of an ABR I'll be able to start the software. Should be interesting . . . My first ever 'real' program. My only ventures into code writing, so far, have been test programs for my hardware! Hope I don't pester you guys too much :roll: I know what I'd 'like' the program to look like . . . It's a case of whether I'm up to 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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1024MAK
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Re: New Project, Super Games Cartridge

Postby 1024MAK » Thu Nov 20, 2014 9:11 am

daveejhitchins wrote:Bad news: I don't know where I was when I did the first design (^above^) - What a load of poo! #-o I'd, somehow, got it in my head that a 4 to 10 decoder was required (should be a page latch driven from the data BUS)
When I was looking at what you posted, I did wonder what system you were using. It did look more complicated than I expected.

Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
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Garrettimus
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Re: New Project, Super Games Cartridge

Postby Garrettimus » Tue Dec 02, 2014 9:17 am

Hey, Dave! :D

Any news on this?

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daveejhitchins
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Re: New Project, Super Games Cartridge

Postby daveejhitchins » Wed Dec 03, 2014 8:31 am

Garrettimus wrote:Hey, Dave! :D

Any news on this?
Still waiting for news of the EEPROMS from my supplier. Mainly: What package style they have managed to secure for me and how many. It seems, suddenly, they have all gone up in price :?

More news as-and-when I find out. Can't progress with the layout until I get the above information.

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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daveejhitchins
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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Tue Jan 06, 2015 4:11 pm

Update on the Project:

-> EEPROMs in stock and all tested OK - 3min each to Blank, Program and Verify at 3 Voltages <- and that's my fast programmer :shock:
-> PCBs on order
-> GAL files written and checked <- Compile OK

All attached:
MGC Schematic 6-1-15.JPG
MGC PCB Comp Side 6-1-15.JPG
MGC PCB None Comp Side 6-1-15.JPG

Code: Select all

Name     Mega Games Cartridge IC2 ;
PartNo   IC2 ;
Date     06/01/2015 ;
Revision 01 ;
Designer Dave Hitchins ;
Company  Retro Hardware ;
Assembly None ;
Location IC2 ;
Device   g22v10 ;

/* *************** INPUT PINS *********************/
PIN 1   = DCK1                          ; /* Delayed Clock from Pin 23       */
PIN 2   = nOE                           ; /* Electron slot nOE               */
PIN 3   = nRST                          ; /* System Reset - All outputs to 0 */
PIN 4   = T2                            ; /* CPU Clock                       */
PIN 5   = EMRnW                         ; /* Elktron or Master Read notWrite */
PIN 7   = nPFC                          ; /* Not Page &FC                    */
PIN 8   = A3                            ; /* Address line A3                 */
PIN 9   = D1                            ; /* Data 1                          */
PIN 10  = D2                            ; /* Data 2                          */
PIN 11  = D0                            ; /* Data 0                          */

PIN 13  = nA4567                        ; /* (A4+A+A6+A7) from IC3           */
PIN 14  = QA                            ; /* Electron slot Bank select       */
/* *************** OUTPUT PINS *********************/
PIN 15  =  A21                          ; /* Address line 21 to ROM          */
PIN 16  = !RnOE                         ; /* ROM Not Output Enable           */
PIN 17  =  RPM                          ; /* Page Mode (internal only)       */
PIN 18  =  RBS                          ; /* Bank Select (internal only)     */
PIN 19  = !RnCE                         ; /* ROM Not Chip Enable             */
PIN 20  =  RWE                          ; /* Write Enable (internal only)    */
PIN 21  =  CKO2                         ; /* Clock output to IC3 pin 1       */
PIN 22  = !nW                           ; /* ROM Not Write                   */
PIN 23  =  CKO1                         ; /* Clock Output to Pin 1           */

/* **************** EQUATIONS **********************/

A21     = !RPM & QA
        #  RPM & RBS                    ; /* Address line 21 to ROM          */
/* A21=Bank Select. With PM=L A21 is controlled by QA 'slot bank selector'   */
/*                  With PM=H A21 is controlled by BS 'Bank Select' -        */
/*                     Always in the higher ROM number - Controlled by RnCE  */

RWE.D    =  D0                          ; /* Write Enable L=Inhibit H=Enable */
RWE.AR   = !nRST                        ; /* Main CPU Reset - Sets Output=L  */
RWE.OE   = 'b'1                         ; /* Always enabled                  */
RWE.SP   = 'b'0                         ; /* Never preset                    */

RBS.D    =  D1                          ; /* Bank Select L=LowRom H=HighROM  */
RBS.AR   = !nRST                        ; /* Main CPU Reset - Sets Output=L  */
RBS.OE   = 'b'1                         ; /* Always enabled                  */
RBS.SP   = 'b'0                         ; /* Never preset                    */

RPM.D    =  D2                          ; /* Page Mode L=2Pages H=1Page      */
RPM.AR   = !nRST                        ; /* Main CPU Reset - Sets Output=L  */
RPM.OE   = 'b'1                         ; /* Always enabled                  */
RPM.SP   = 'b'0                         ; /* Never preset                    */

RnOE    = !nOE & EMRnW                  ; /* Not Output enable to ROM        */
/* Master or Electron W/nW - Selected by SN74LVC97, one of two decoder       */

RnCE    = !RPM & T2 & !nOE
        #  RPM & T2 & !nOE &  QA        ; /* Not Chip enable to ROM          */
/* ROM nCE active when (PM=L AND QA=L OR QA=H) OR (PM=H AND QA=H)            */

nW      =  RWE & !EMRnW                 ; /* Not Write to ROM                */
/* Writes to ROM controlled by WE - WE default=L Inhibit                     */

CKO2    = !nPFC & !nA4567 &  A3 & !EMRnW  & T2
                                        ; /* Clock to Pin 1 IC3 - Write only */
/* Address for Control Latch=&FC08 to &FC0F - Gated with T2                  */

CKO1    = !nPFC & !nA4567 & !A3 & !EMRnW  & T2
                                        ; /* Clock to Pin 1 IC2 - Write only */
/* Address for ROM Address Latch=&FC00 to &FC07 - Gated with T2              */

Code: Select all

Name     Mega Games Cartridge IC3 ;
PartNo   IC2 ;
Date     06/01/2015 ;
Revision 01 ;
Designer Dave Hitchins ;
Company  Retro Hardware ;
Assembly None ;
Location IC3 ;
Device   g22v10 ;

/* *************** INPUT PINS *********************/
PIN 1   = DCK2                    ; /* Delayed Clock from IC2          */
PIN 2   = NRST                    ; /* System Reset - All outputs to 0 */
PIN 3   = D7                      ; /* Data 7                          */
PIN 4   = D6                      ; /* Data 6                          */
PIN 5   = D5                      ; /* Data 5                          */
PIN 6   = D4                      ; /* Data 4                          */
PIN 7   = D3                      ; /* Data 3                          */
PIN 8   = D0                      ; /* Data 0                          */
PIN 9   = D1                      ; /* Data 1                          */
PIN 10  = A4                      ; /* Address line 4                  */
PIN 11  = D2                      ; /* Data 2                          */

PIN 13  = A5                      ; /* Address line A5                 */
PIN 22  = A6                      ; /* Address line A6                 */
PIN 23  = A7                      ; /* Address line A7                 */

/* *************** OUTPUT PINS *********************/
PIN 14  = !A4567                  ; /* (A4+A5+A+A7) to IC3             */
PIN 15  =  RA20                   ; /* Address line 20 to ROM          */
PIN 16  =  RA19                   ; /* Address line 19 to ROM          */
PIN 17  =  RA18                   ; /* Address line 18 to ROM          */
PIN 18  =  RA17                   ; /* Address line 17 to ROM          */
PIN 19  =  RA16                   ; /* Address line 16 to ROM          */
PIN 20  =  RA15                   ; /* Address line 15 to ROM          */
PIN 21  =  RA14                   ; /* Address line 14 to ROM          */

/* **************** EQUATIONS **********************/

RA14.D  =  D0                     ; /* Address line 14 to ROM          */
RA14.AR = !NRST                   ; /* Main CPU Reset - Sets Output=L  */
RA14.OE = 'b'1                    ; /* Always enabled                  */
RA14.SP = 'b'0                    ; /* never preset                    */

RA15.D  =  D1                     ; /* Address line 15 to ROM          */
RA15.AR = !NRST                   ; /* Main CPU Reset - Sets Output=L  */
RA15.OE = 'b'1                    ; /* Always enabled                  */
RA15.SP = 'b'0                    ; /* never preset                    */

RA16.D  =  D2                     ; /* Address line 16 to ROM          */
RA16.AR = !NRST                   ; /* Main CPU Reset - Sets Output=L  */
RA16.OE = 'b'1                    ; /* Always enabled                  */
RA16.SP = 'b'0                    ; /* never preset                    */

RA17.D  =  D3                     ; /* Address line 17 to ROM          */
RA17.AR = !NRST                   ; /* Main CPU Reset - Sets Output=L  */
RA17.OE = 'b'1                    ; /* Always enabled                  */
RA17.SP = 'b'0                    ; /* never preset                    */

RA18.D  =  D4                     ; /* Address line 18 to ROM          */
RA18.AR = !NRST                   ; /* Main CPU Reset - Sets Output=L  */
RA18.OE = 'b'1                    ; /* Always enabled                  */
RA18.SP = 'b'0                    ; /* never preset                    */

RA19.D  =  D5                     ; /* Address line 19 to ROM          */
RA19.AR = !NRST                   ; /* Main CPU Reset - Sets Output=L  */
RA19.OE = 'b'1                    ; /* Always enabled                  */
RA19.SP = 'b'0                    ; /* never preset                    */

RA20.D  =  D6                     ; /* Address line 20 to ROM          */
RA20.AR = !NRST                   ; /* Main CPU Reset - Sets Output=L  */
RA20.OE = 'b'1                    ; /* Always enabled                  */
RA20.SP = 'b'0                    ; /* never preset                    */

A4567   = !A4 & !A5 & !A6 & !A7   ; /* When A4, A5, A6, A7 = 0  Out=0  */

MEGA GAMES CARTRIDGE.zip
(109.19 KiB) Downloaded 51 times


Check, anyone [-o<

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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Garrettimus
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Re: Mega Games Cartridge for the Electron and Master

Postby Garrettimus » Tue Jan 06, 2015 4:26 pm

I would if I had knowledge in Electronics! LOL! :lol:

Anyway, everything looks fantastic! =D> =D> =D> =D>

Congratulations, mate!

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1024MAK
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Re: Mega Games Cartridge for the Electron and Master

Postby 1024MAK » Wed Jan 07, 2015 9:49 am

daveejhitchins wrote:Cheque, anyone [-o<
What! You want money as well? I thought you got that retirement job to pay for all this :lol:

Oh, and I love the new name:
daveejhitchins wrote:Elktron
8)

Wrong time of day to check your published details. Maybe my brain will have rebooted by the weekend :roll:

Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki‬ - for answers to many questions...

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daveejhitchins
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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Wed Jan 07, 2015 11:43 am

Cheque - Must have had pay-day on my mind :roll: As for 'Elktron' Well, what can I say? Perhaps D'oh! again :lol:

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

paulb
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Re: Mega Games Cartridge for the Electron and Master

Postby paulb » Wed Jan 21, 2015 11:31 am

Drifting slightly off topic, I recently had a go at interfacing an Arduino to some Am29F010 flash memory that davidb obtained a while ago, and after much fumbling managed to program it with some ROM images. The Am29F010 is a DIP component that has better compatibility than the AT29C256 with the standard ROM pin layout, as far as I can tell, and although the referenced vendor doesn't sell either of these any more, the same distinction appears to be true for their successors. For example, the Am29F020.

(The compatibility is enhanced with these Am29F* devices because they share the pin layout for all but the VCC pin, which if the flash device is aligned appropriately, appears at the A17 pin - if present - on the flash device. Thus, the amount of re-routing is reduced for ad-hoc socket-on-socket antics.)

I see that the mega games cartridge uses a TSOP component now, which makes it incompatible with these DIP components, and it looks like the boards are being (or have been) made, but I wondered what kind of other avenues exist for deploying the DIP variants instead. I guess they'd work with anything that has a plain ROM socket, albeit with some socket-on-socket modifications similar to, but less troublesome than, those described in the EEPROM thread.

Is anyone interested in making or modifying ROM cartridges for this purpose? A DIP-socketed version of the mega games cartridge, perhaps?

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daveejhitchins
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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Wed Jan 21, 2015 3:45 pm

I managed to pick-up a good quantity of AMD AM29F010B-70ED (TSOP 128x8) and had planned to make up some ROM boards with 'switches' for the ROM selection, trying to keep it simple! MartinB's program for the AT28C256 should work <- with some modification! (As a by - Martin has VERY kindly offered [with his arm up his back :- ] to modify his code as a 'driver' for the Mega Games Cartridge) So, You won't need DIP versions as you'll be able to program in-place :D

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

paulb
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Re: Mega Games Cartridge for the Electron and Master

Postby paulb » Wed Jan 21, 2015 4:21 pm

daveejhitchins wrote:I managed to pick-up a good quantity of AMD AM29F010B-70ED (TSOP 128x8) and had planned to make up some ROM boards with 'switches' for the ROM selection, trying to keep it simple!


I thought the design permitted ROM selection using the ULA paging register, or did I get my hopes up after seeing gate arrays on your board? :wink:

daveejhitchins wrote:MartinB's program for the AT28C256 should work <- with some modification! (As a by - Martin has VERY kindly offered [with his arm up his back :- ] to modify his code as a 'driver' for the Mega Games Cartridge) So, You won't need DIP versions as you'll be able to program in-place


Are there any open designs for cartridges that could be made to hold the DIP versions? Or even any readily available cartridges?

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daveejhitchins
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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Wed Jan 21, 2015 6:41 pm

paulb wrote:I thought the design permitted ROM selection using the ULA paging register, or did I get my hopes up after seeing gate arrays on your board? :wink:
Yes, the MGC is purely software driven with all the latching and decoding done in 2 x 22V10 PLDs. I mentioned the AM29F010B-70ED with a new project in mind >> 8 x 16K ROM cartridge - ROMs selectable by switches (to keep cost and/or complexity down to a minimum)

paulb wrote:Are there any open designs for cartridges that could be made to hold the DIP versions? Or even any readily available cartridges?
I think there is a 'switch-selectable' cartridge that I've seen on e-Bay, but I take it you're wanting to use these DIP parts?

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 and Master

Postby MartinB » Wed Jan 21, 2015 9:29 pm

Paul - aren't most of those bigger eeproms that you're suggesting 32-pin DIP? To be as drop-in as possible in the Beeb range, they really need to be 28-pin which is likely going to mean they're 32k x 8 like the AT28C256 that I've been playing with. Although, I could easily have missed the point of what you're asking? (Wouldn't be a first for me.... :roll: :lol: )

Anyway, in answer to your question about cartridges, I did modify a standard Elk/Master cart to take a 28C256 acting as two standard roms. If you didn't see it, the details are here.

Dave H wrote: (As a by - Martin has VERY kindly offered [with his arm up his back :- ] to modify his code as a 'driver' for the Mega Games Cartridge)
Aha, so that explains the pain I'm feeling in anticipation then.....

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Re: Mega Games Cartridge for the Electron and Master

Postby paulb » Wed Jan 21, 2015 11:32 pm

MartinB wrote:Paul - aren't most of those bigger eeproms that you're suggesting 32-pin DIP? To be as drop-in as possible in the Beeb range, they really need to be 28-pin which is likely going to mean they're 32k x 8 like the AT28C256 that I've been playing with. Although, I could easily have missed the point of what you're asking? (Wouldn't be a first for me.... :roll: :lol: )


No, you've observed correctly that they're 32-pin DIP, and that means that any usage with 28-pin sockets would need to involve some double-socket antics, I guess. I've never tried this myself, but duikkie seemed to be doing that kind of thing in your EEPROM thread, although now I look at it again, the AT28C256 is 28-pin DIP (in one form) and would be somewhat more amenable to socket-in-socket tricks, although if you're going to do this or use carrier boards, it ultimately stops mattering how many pins there are: you aren't putting anything straight into the original socket.

MartinB wrote:Anyway, in answer to your question about cartridges, I did modify a standard Elk/Master cart to take a 28C256 acting as two standard roms. If you didn't see it, the details are here.


I'll take another look, thanks!

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Re: Mega Games Cartridge for the Electron and Master

Postby paulb » Wed Jan 21, 2015 11:38 pm

daveejhitchins wrote:
paulb wrote:I thought the design permitted ROM selection using the ULA paging register, or did I get my hopes up after seeing gate arrays on your board? :wink:
Yes, the MGC is purely software driven with all the latching and decoding done in 2 x 22V10 PLDs. I mentioned the AM29F010B-70ED with a new project in mind >> 8 x 16K ROM cartridge - ROMs selectable by switches (to keep cost and/or complexity down to a minimum)

paulb wrote:Are there any open designs for cartridges that could be made to hold the DIP versions? Or even any readily available cartridges?
I think there is a 'switch-selectable' cartridge that I've seen on e-Bay, but I take it you're wanting to use these DIP parts?


Yes, using such DIP devices would be highly desirable.

Indeed, it also seems a bit more retro to use something similar to what would have been used originally. As for the switching, some simple manual switches is an easy enough approach for single ROM images intended for games use: the ULA paging mechanism would really only be beneficial for double ROMs (Jungle Journey, for example) and applications needing to expose multiple ROMs in software.

I'd need to check to see whether you're supposed to offer more than two ROMs via the paging register from a single cartridge, but I don't see anything objectionable about a "ROMBOX" cartridge in principle. :)

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Re: Mega Games Cartridge for the Electron and Master

Postby MartinB » Thu Jan 22, 2015 3:40 pm

Paul wrote:I'd need to check to see whether you're supposed to offer more than two ROMs via the paging register from a single cartridge, but I don't see anything objectionable about a "ROMBOX" cartridge in principle.
To select individual 16k roms within a standard cartridge, both the Elk and Master interfaces only provide ROMQA which is a single, two-state signal and in both cases reflects the state of the LSB of the respective machine's rom paging register. Without additional bespoke circuitry, this limits the number of roms accessible in a standard cartridge to two.

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Re: Mega Games Cartridge for the Electron and Master

Postby paulb » Fri Jan 23, 2015 10:51 pm

I was just looking at the "Acorn Electron Cartridge Interface Specification" (AppNote 014) and certainly, with only ROMQA available reflecting the LSB of &FE05/&FE30, the ULA paging isn't able to make more than two ROMs selectable, as already noted.

But then I saw a few other things...

On the Electron only: "nROMSTB is an active low input using TTL levels which selects the location &FC73. This is intended to be used as a paging register."

There's also a mention of the memory maps, and at least as far as the Master is concerned: "&FCFF Paging register for memory in the &8000 to &BFFF region. Paging logic has to be implemented in each cartridge as necessary." Presumably nINFC and nINFD would be used to support this paging in the cartridge.

On the Electron, the page &FC and &FD mechanism (JIM and FRED, I think) doesn't seem supportable in a cartridge because only address lines A0 through A13 are exposed and only nROMSTB might expose anything outside that 16K range.

So maybe paging might be supportable through one of the above convoluted mechanisms.

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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Sun Feb 08, 2015 8:40 am

MGC Test update: Didn't take enough bits-and-bobs to Halifax to carry out testing properly. So, I've had a little time this last week and made some progress.

The data latches are now working. I needed > 110ns delay, for the data latch clock, so I've used 220R and 1n (had them in my box) giving ~220ns delay. I can now page-in the various games that I pre-programmed into the EEPROM :D

I can't, at the moment, figure out the call required to get the OS to re-scan the ROMs so that I can 'see' them when I use *ROMS. Anyone have ideas on this front?

The general idea is to have a 'flag', stored with the Game title, that will inform the software how-to-load that game. This will allow various mechanisms to be present for that job e.g. If it's a Cartridge ROM based Game - use the ROM FS for loading. However, if it was a Tape game, originally, it would, probably, require a dedicated loader etc.

I can now concentrate on doing more work on the Menu program.

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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Sat Feb 14, 2015 9:59 pm

More testing today:

Before I fitted the EEPROM I programmed-in some of the ROM cartridges e.g. Hopper, snapper, View, Viewsheet.

I was having a gander at the hefty documentation that comes with the IFEL ROM/RAM board for the Beeb. And found the way to force a ctrl brk through software - Of course you all knew it - right?

I can now select a page and run the game directly from the key board with:

Hopper: ?&FC00=x:?FE4E=127:CALL!-4 and away you go.
x=
Snapper on Page 4
View on page 9
Vieswheet on page 10

I'll Programm some double ROMs for the next batch I make.

All looking good. Tomorrow I'll do some more of the Menu Programming.

Dave H :D
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Re: Mega Games Cartridge for the Electron and Master

Postby sweh » Sat Feb 14, 2015 10:32 pm

daveejhitchins wrote:Hopper: ?&FC00=x:?FE4E=127:CALL!-4 and away you go.

Sorry if this has been answered earlier upthread...

Can the base address be changed? eg by soldering a link cable on the board? The problem with using FC00 is this _could_ conflict with other devices on the 1Mhz bus; having optional addresses will increase compatibility with odd hardware setups :-)

This was common BITD; eg Mike Cook's "4 user port" design at http://sweh.spuddy.org/Beeb/Images/4_us ... ematic.jpg where you can see a "address link"; in this case he was addressing in bunch of &20 offset (FC00;FC20;FC40...)
Rgds
Stephen

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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Sun Feb 15, 2015 12:20 am

sweh wrote:
daveejhitchins wrote:Hopper: ?&FC00=x:?FE4E=127:CALL!-4 and away you go.

Sorry if this has been answered earlier upthread...

Can the base address be changed? eg by soldering a link cable on the board? The problem with using FC00 is this _could_ conflict with other devices on the 1Mhz bus; having optional addresses will increase compatibility with odd hardware setups :-)

This was common BITD; eg Mike Cook's "4 user port" design at http://sweh.spuddy.org/Beeb/Images/4_us ... ematic.jpg where you can see a "address link"; in this case he was addressing in bunch of &20 offset (FC00;FC20;FC40...)
I chose FC00 as it's listed as Acorn Test (or something similar). The good news is it can be changed in the PLD. It would, I think, be 'bodgeable' but would require cutting tracks and altering software. The best thing would be to have lots of testing done by people who could reprogram the PLD and change the software so we can 'fix' this before general release. Volunteers welcome :D

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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Wed Feb 18, 2015 8:24 am

First draft of the Menu . . . Just to prove concept. Currently written in BASIC but will need to have some assembler to speed-up some of the parts. Only 4 entries, for now. The next batch will have more. The current Menu Layout will not be final . . . I think we can do better than that. With Dave's permission (hoglet) I will take a peek at how he's built the Atom menu, and maybe learn a few things!

I'm now ready to add to the list of games that can be run, however that mechanism may be. You know, the ones you've all been working on . . . :lol:

The menu is currently working from an ABR. One 16K block holding the menu and the second 16K block holding the list of Games, Utilities and Languages. Works on the Electron only, so far. The method of deciding which machine its in has broken, since Jonathan gave me it at the Halifax before last. The Menu will only show which items will work on the system you're using.
MGC Menu1.jpg


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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Sun Mar 29, 2015 9:37 am

OK . . . I'm now in need of Games, Utilities or Languages for the MGC <- Probably more games than anything else, please. For the Master or the Electron! Even better, for both!

Suggestions for Utilities . . . These can be in pairs e.g. ADT-ADI etc.

Currently I have all the Cartridge Games, and Languages (easy :oops: ) I know there are other games that have been ROMed e.g. Chuckie Egg - Missile Control (can't find these?). Are there any others out there? Has anyone managed to get any games to run, from sideways RAM, that they could provide?

I'm hoping to have a 'working' version for the Wakefield show [-o<

Dave H :D

I'll be 'editing' my first post with the current list of Games, Languages and Utilities, so that they're easy to find.
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Re: Mega Games Cartridge for the Electron and Master

Postby JoolsH » Sun Mar 29, 2015 6:28 pm

It would be cool to have my Cavern Racer game on it. Unfortunately, at the current rate of development I'll have finished it by the end of 2018 :roll:

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Re: Mega Games Cartridge for the Electron and Master

Postby richardtoohey » Sun Mar 29, 2015 7:07 pm

daveejhitchins wrote:I know there are other games that have been ROMed e.g. Chuckie Egg - Missile Control (can't find these?). Are there any others out there? Has anyone managed to get any games to run, from sideways RAM, that they could provide?
Hi, Dave.

What does ROMming a game entail? Or does asking the question show I'm not going to be able to help much? :oops:

I just assumed a "ROM version" was the same files but would be using ROM FS, or is there more to it than that?

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Re: Mega Games Cartridge for the Electron and Master

Postby davidb » Sun Mar 29, 2015 9:04 pm

I rediscovered the collection of ROMs at the NVG FTP site via Retro-kit's archive of The BBC Lives! Unfortunately, I think we're dealing with BBC ROMs only on that site.

Did you try the ROMs from Jungle Journey, available from the Downloads section of the home page? I know that dual-ROM games might be tricky to deal with, but it may be worth trying.

I can also send you a work-in-progress Castle Raider ROM image if you want. It only needs one ROM slot, so shouldn't cause any problems.

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Re: Mega Games Cartridge for the Electron and Master

Postby CMcDougall » Sun Mar 29, 2015 10:16 pm

daveejhitchins wrote:other games that have been ROMed e.g. Chuckie Egg - Missile Control (can't find these?)

*cough*
viewtopic.php?f=1&t=8246&start=30#p97677
but these are mine as a kid, so only in ROM FS 8)
could be easily done to change to a *CHUCKIE like Mark@RC has done.
PS Mark, need to change instructions for cEgg:
http://www.ebay.co.uk/itm/ACORN-BBC-MIC ... 6016.l4276
is it's not to move Snapper, he's called Pete :shock:
ImageImageImage

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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Mon Mar 30, 2015 6:56 am

JoolsH wrote:It would be cool to have my Cavern Racer game on it. Unfortunately, at the current rate of development I'll have finished it by the end of 2018 :roll:
We'll still be here =D>

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
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Re: Mega Games Cartridge for the Electron and Master

Postby richardtoohey » Mon Mar 30, 2015 7:00 am

richardtoohey wrote:What does ROMming a game entail? Or does asking the question show I'm not going to be able to help much? :oops:

I just assumed a "ROM version" was the same files but would be using ROM FS, or is there more to it than that?
C'mon, someone put me out of my misery, please! [-o<

Is there something special required?

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Re: Mega Games Cartridge for the Electron and Master

Postby daveejhitchins » Mon Mar 30, 2015 7:01 am

richardtoohey wrote:What does ROMming a game entail? Or does asking the question show I'm not going to be able to help much?
You're right, it's making the game run from the ROM Filing System. I'm hoping that the ABR 'Make ROM' utility will do the job - at least for games that will fit into a 16K block. We may have to look at one of the 32K Games Cartridges to see how that works . . . Of course, the ROM FS may already support the 32K already?

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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