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Amstrad GX4000 / Plus cartridge PCB

Started by Chinnery, 10:02, 27 May 19

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tjohnson

An HC chip works fine, I've tried it.

eto

Quote from: tjohnson on 00:09, 09 January 23An HC chip works fine, I've tried it.
Also with Shinings modified circuit? Or just the original NoAcid?

Duca750

Quote from: eto on 23:56, 08 January 23
Quote from: Duca750 on 18:54, 08 January 23Hola, este diseño permite 74HC112 o es necesario un chip original?
74??112 - Todavía tengo que confirmar si HC funcionará o si se requiere AC o F. He pedido un conjunto de circuitos integrados, así que puedo probarlo pronto.

Todavía no he probado el diseño final y necesito comprobar si encaja en alguno de los casos impresos en 3D disponibles o si tengo que ajustar el diseño. Un par de semanas probablemente antes de que pueda lanzar el PCB.
Estoy esperando nuevas noticias. ¡Gracias!

eto

Quote from: eto on 23:56, 08 January 2374??112 - I have to confirm yet, if HC will work or if AC or F is required. I have ordered a set of ICs, so I can test that soon. 
fyi: I have tested a previous version of the PCB with Shinings modification of the NoAcid with 74xx112 of type ACT,AC,HC,HCT and F. All work. Reset also works. 

New PCBs haven't arrived yet, so it will still need some time until I can test the final PCB layout. 

Cwiiis

Quote from: eto on 01:15, 15 January 23
Quote from: eto on 23:56, 08 January 2374??112 - I have to confirm yet, if HC will work or if AC or F is required. I have ordered a set of ICs, so I can test that soon.
fyi: I have tested a previous version of the PCB with Shinings modification of the NoAcid with 74xx112 of type ACT,AC,HC,HCT and F. All work. Reset also works.

New PCBs haven't arrived yet, so it will still need some time until I can test the final PCB layout.
I find that stability with expansions is greatly affected using these carts - the usifac in particular is completely unusable with anything except the stock basic cart. It'd be neat to test expansions with these various chips too, to see if any are more stable than the others...

eto

Quote from: Cwiiis on 12:42, 15 January 23the usifac in particular is completely unusable with anything except the stock basic cart.
What happens with the Usifac? Lock during boot after the initial messages appear on screen?

I can test later today if I have similar issues or if any of the chips works better than the other. 

Cwiiis

Quote from: eto on 13:00, 15 January 23
Quote from: Cwiiis on 12:42, 15 January 23the usifac in particular is completely unusable with anything except the stock basic cart.
What happens with the Usifac? Lock during boot after the initial messages appear on screen?

I can test later today if I have similar issues or if any of the chips works better than the other.

Yes, lock-up on boot or if it gets further than that, lock-up during |help output. On my 6128+ with tape port, it also often triggered the tape relay and "Press return to play" message.

eto

Quote from: Cwiiis on 13:07, 15 January 23Yes, lock-up on boot or if it gets further than that, lock-up during |help output. On my 6128+ with tape port, it also often triggered the tape relay and "Press return to play" message.
I tried it with several variations. In no variation I had a lock during boot.

However I could only start a game with a single cartridge: This is an original cartridge with EPROM replaced and Parados installed.

With all other cartridges I can select an image but once FDC emulation is activated, the system locks. Original BASIC cartridge or cartridge with NoAcid behave identical. No difference between HC, AC and F.

Since we have a similar issue on some CPC464s, where it locks during boot after firmware is initialised I got the idea that the Usifac maybe issues the ROMDIS signal slightly too late, so that a fast ROM/Eprom already outputs data to the bus and then the Usifac also outputs data to the bus. Not sure if that is a valid idea.

Duca750

Quote from: eto on 14:31, 15 January 23
Quote from: Cwiiis on 13:07, 15 January 23Sí, bloqueo durante el arranque o, si va más allá, bloqueo durante la salida de ayuda. En mi 6128+ con puerto de cinta, a menudo también activaba el relé de cinta y el mensaje "Presione volver para reproducir".
Lo probé con varias variaciones. En ninguna variación tuve un bloqueo durante el arranque.

Sin embargo, solo pude iniciar un juego con un solo cartucho: este es un cartucho original con EPROM reemplazada y Parados instalado.

Con todos los demás cartuchos, puedo seleccionar una imagen, pero una vez que se activa la emulación FDC, el sistema se bloquea. El cartucho BASIC original o el cartucho con NoAcid se comportan de forma idéntica. No hay diferencia entre HC, AC y F.

Dado que tenemos un problema similar en algunos CPC464, donde se bloquea durante el arranque después de que se inicializa el firmware, tuve la idea de que Usifac tal vez emita la señal ROMDIS un poco demasiado tarde, por lo que una ROM/ Eprom ya envía datos al bus y luego Usifac también envía datos al bus. No estoy seguro si esa es una idea válida.
Hi! new PCB received? You can test ? Thank you!

eto

Quote from: Duca750 on 17:05, 18 January 23Hi! new PCB received? You can test ? Thank you!
No, they will arrive within the next couple of days. But I am also waiting for the 8Mb Eproms which haven't shipped yet (probably due to Chinese new year) and are confirmed for delivery mid of February. Once they arrive I can work on that again. I will update the thread once everything is here and tested. 

Duca750

I am testing with its original cartridge to make a cartridge with 4 Rom with M27C4001.  At the moment the cartridge boots, but I don't understand why I select the option I select, the first ROM always comes out.  For this adaptation, I have cut the tracks where I have soldered the DIP, only the area is used as a support.You cannot view this attachment. You cannot view this attachment.

eto

Quote from: Duca750 on 19:23, 18 January 23I am testing with its original cartridge to make a cartridge with 4 Rom with M27C4001.
Seems good to me. Not sure what is wrong there. Which four ROMs have you been using?

If it's just for that particular use case you can find attached the Gerber files for my proof of concept for a cartridge PCB. It's the one where I tried out Shinings No Asic patch and this works for me. I can't guarantee of course that it works for everyone.

With this PCB you can burn four 128K Roms on a 4Mbit Eprom and select with dip switches. Just add the Dip switch and 10K resistors to the PCB. 

(You can also use this PCB with a 512K Rom. In that case, don't populate the DIP, don't add the 10K resistors, but close the bridges below the 10K resistors. Two 256K Roms will also work. In that case only populate the upper most DIP, add one 10K resistors a the position marked as A18, don't add the other resistor (A17) but close the bridge below that resistor. )


Duca750

#62
Indeed, it's just a test that I wanted to do, ROM 1: burnin rubber+Basic, ROM 2: I think I remember Parados+Basic, ROM 3: Batman and ROM 4: Robocop 2. I'm not good at electronics, a friend from another forum told me I make this scheme, can you confirm if it is correct?  In any case, thank you very much!
You cannot view this attachment.

Duca750

Quote from: eto on 23:56, 08 January 23
Quote from: Duca750 on 18:54, 08 January 23Hola, este diseño permite 74HC112 o es necesario un chip original?
74??112 - Todavía tengo que confirmar si HC funcionará o si se requiere AC o F. He pedido un conjunto de circuitos integrados, así que puedo probarlo pronto.

Todavía no he probado el diseño final y necesito comprobar si encaja en alguno de los casos impresos en 3D disponibles o si tengo que ajustar el diseño. Un par de semanas probablemente antes de que pueda lanzar el PCB.
¡Hola! ¿Podría realizar las pruebas con este nuevo cartucho? ¿Con qué chip 112 es compatible? ¡gracias!

Apollo

Reviving this old thread... any news on this topic?
CPC - My beloved first computer!

eto

I made a new version of the PCB which is more flexible regarding ROM image size and EPROM size.

You can select the ROM image size by creating shorts on the PCB and if your EPROM is bigger than the ROM size, you can use dip switches to select the ROM number. It was originally meant to support even 8MBit ROMs (so up to 8 of the original GX4000 games on a single normal sized cartridge) but I made a mistake there, so although it theoretically is possible, at the moment it requires to cut a trace and solder one wire. I will fix that eventually and then release the Gerbers and 3D printing files for the cartridge case.


Based on that PCB in the meantime also made a "developer" cartridge for my personal use. It's big enough so you can change the EPROM while the cartridge stays inside the Plus. ROM size and number is adjusted by switches or jumpers. You can have 64KB to 512KB ROM image sizes and 1MBit to 8MBit EPROM sizes. It's quite convenient e.g. to have diagnostics and several OS versions on the same cartridge and just need to select the right one.




eto

Quote from: eto on 08:26, 27 September 23I will fix that eventually
AAAAAAND fixed... 

I just ordered the new PCBs

Apollo

Looks lovely  8)

I am working atm also on a cartridge project and my first prototype PCBs but there is still much work to do.  ;)
CPC - My beloved first computer!

destroyer

Hello Eto, excellent work. Is this PCB functional?...I would like to try creating a cartridge...

darkhalf

Quotetested a previous version of the PCB with Shinings modification of the NoAcid with 74xx112 of type ACT,AC,HC,HCT and F. All work. Reset also works

Similar to bobmoo79 I've had trouble with the 'shining' version. My approach was modifying existing working Chinnery 2.10.1 cartridges (still using 74HC112N)

Steps were:
1. Cutting the R1 (4.7K) line from VCC and routing CCLR
2. Changing C1 from 100nf (104) to 0.1nf (101)

The results are the CPC464 plus starts but with white green or partial graphics on the cart. I've reverted Step 1 of the 'Shining' changes and the games start fine

Be interested to try the Eto version when that is available 

Pictured are the modifications. Any ideas on this one?
CPC464/GT64, CPC464 Plus/CTM640, 2 x CPC6128/CTM644

eto

Quote from: destroyer on 11:35, 21 November 23Hello Eto, excellent work. Is this PCB functional?...I would like to try creating a cartridge...
I made several cartridges with it and it works on my GX4000 and Plus 6128. However the most recent version is more flexible.

Quote from: darkhalf on 05:05, 09 December 23Be interested to try the Eto version when that is available 
Sorry, I was moving house and the CPC stuff did not have priority. I hope I will be able to test the latest PCB within the next few weeks and then document and publish it. But most likely after Christmas.

Generally speaking it works (previous version with just a slightly different layout was tested with GX4000 and 6128 plus) and can hold up to eight 128K images in a single Eprom, selectable with DIP switches. 



Cwiiis

Just a note, I've updated my cartridge case design - I strongly advise not using the old model, there isn't really enough space inside for the PCB with an EPROM soldered (it's about 0.3mm too narrow). PLA is flexible enough that this doesn't matter too much, but it will introduce problems with more rigid printing materials (like resin). This updated design is very close to the original; of all the reproductions I've seen, I believe it to be the closest, and it remains a feasible print with FDM. It has more than enough room for a soldered PCB inside and a good amount of tolerance if you don't solder the EPROM completely flat - this room was made by narrowing the walls, which also makes it a cheaper print.

Model files, details on where you can get it printed, etc. are available on the Thingiverse page: https://www.thingiverse.com/thing:4943077

It's licenced CC BY-NC-SA - I have granted @overange an exception as he's agreed to share his new PCB designs (which work with this shell as they have the same dimensions as Chinnery's original PCB). If you need an exception, please send me a message - of course, you're free to use this for personal use :)

I've attached a couple of little preview photos of an FDM print, I'm currently waiting on resin prints.

Captain Past

I have a question for all you GX4000/Plus cart fans here...
A few years ago I've ordered a bunch of GX4000 cart PCBs to make a cart for myself from time to time. So now the problem was to get a bunch of cart shells as well. I was never happy how 3D printed cases looked (from what I've seen on photos) so I've spoken to a guy who owns a machine to produce injection moulded parts and who had produced C64 cart shells previously.
He said he could produce the GX4000 shells for under 4 € a piece. Now, that was before the whole world went mad of course, so I'd need to ask him if that price is still realsitic. The problem is of course - and that's why I want to ask here - to produce the crazy expensive moulds he needs an initial order of at least 500 shells.

Now to the question: with the relatively small GX4000/Plus models userbase, is it realistic to find enough people interested in new shells to get to 500 pieces?
After that we'd finallly have the shells readily availlable to order (the guy is based in Austria / he doesn't sell quantities smaller than 10) whenever someone maybe wants to create a physical realease of his new game e.g.
So, what do you guys think? :)



eto

Sounds interesting. 

Would 4€ (or whatever it is now) the "retail" price? Or just his cost? 


Captain Past

Well he's selling the C64 cart shells for 3,60 €, and the Gx4000 shells would be in the same general range (depending on how complicated the moulds are).

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