CPCWiki forum

General Category => Amstrad CPC hardware => Topic started by: Chinnery on 12:02, 27 May 19

Title: Amstrad GX4000 / Plus cartridge PCB
Post by: Chinnery on 12:02, 27 May 19
I'm releasing my current design for the Amstrad Plus Cartridge PCB.


There is one known issue as far as I'm aware - if you have a reset switch on your Plus machine, there is about a 50/50 chance the board will not initialise properly if not using the Acid option. A power cycle ALWAYS initialises properly. I know there is a fix for this but help has not been forthcoming.


The 2 diagrams attached aught to help with component options for the Acid variant and Non-acid variant. Obviously you will always need an eprom. I have labelled on the silk screen what components go where so it should be easy to sort out.


The ZIP file contains both the eagle design schematics and the board layout file, so people who like to tinker can. There is a sub folder called "gerbers" which you can just upload to your PCB manufacturer of choice to get them produced. I've tried both JLCPCB and Seeed Studio Fusion with great results.


Enjoy!
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: TotO on 12:39, 27 May 19
Cool! Any project with it?  :)
Yes, the no acid design (nocash) have this known problem.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: 00WReX on 12:40, 27 May 19
Very nice of you to provide this to the community.

Excellent work.

Thank you.
Cheers,
Shane
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Chinnery on 13:31, 27 May 19
Quote from: TotO on 12:39, 27 May 19
Cool! Any project with it?  :)
No projects - all my project seem to reference the wrong items anyway  ;D  (Eagle noob)

Quote from: TotO on 12:39, 27 May 19
Yes, the no acid design (nocash) have this known problem.
I've heard there is a workaround, but I've had no joy in finding this out. I use these for GX4000 stuff anyway, so no great harm.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Bryce on 13:41, 27 May 19
Quote from: Chinnery on 13:31, 27 May 19
No projects - all my project seem to reference the wrong items anyway  ;D  (Eagle noob)
I've heard there is a workaround, but I've had no joy in finding this out. I use these for GX4000 stuff anyway, so no great harm.

The workaround would most likely involve taking the reset signal to the cartridge which wouldn't be praticle or at least mean modding the CPC.

Bryce.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: 00WReX on 10:44, 23 June 19
Thanks to @Chinnery (http://www.cpcwiki.eu/forum/index.php?action=profile;u=2434) for providing the Gerbers, I had a batch of boards made up just for fun.

I have just finished 5 boards for my own 'Arcade Classics" collection, and they work perfectly.

Cartridges made:                                                  EPROM USED:
1)Frogger - The 'Executioner' arcade port 2007          M27C2001
2)Ghosts'n Goblins GX4000 - Xifos 2018                    M27C2001
3)Space Invaders Arcade Emulator - 40Crisis 2016     M27C2001
4)Bomb Jack I - Phantomz conversion update             M27C4001
5)Scramble - PuzCPC 2019                                        M27C4001

Next plan is to get some 3D printed cases made up, and put some stickers on them to make them appear somewhat professional.

 [ This attachment cannot be displayed inline in 'Print Page' view ]  

Cheers,
Shane
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Gryzor on 16:22, 24 June 19
How long till copies of Pang and Chase HQ XIII appear on ebay? :D
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: tjohnson on 00:55, 25 June 19
Quote from: Gryzor on 16:22, 24 June 19
How long till copies of Pang and Chase HQ XIII appear on ebay? :D
Good point, I'm sure people would like to see Chase HQ 2 appear, one day maybe one day.....
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: BeaglzNZ on 01:59, 24 August 21

Just wondering if you have managed to create a STL for a case for these cartridges? I have got a few PCBs and awaiting parts to assemble - any idea if there is enough clearance for a ZIF socket?
Cheers,
Antony

Quote from: 00WReX on 10:44, 23 June 19
Thanks to @Chinnery (http://www.cpcwiki.eu/forum/index.php?action=profile;u=2434) for providing the Gerbers, I had a batch of boards made up just for fun.

I have just finished 5 boards for my own 'Arcade Classics" collection, and they work perfectly.

Cartridges made:                                                  EPROM USED:
1)Frogger - The 'Executioner' arcade port 2007          M27C2001
2)Ghosts'n Goblins GX4000 - Xifos 2018                    M27C2001
3)Space Invaders Arcade Emulator - 40Crisis 2016     M27C2001
4)Bomb Jack I - Phantomz conversion update             M27C4001
5)Scramble - PuzCPC 2019                                        M27C4001

Next plan is to get some 3D printed cases made up, and put some stickers on them to make them appear somewhat professional.

 

Cheers,
Shane
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Bryce on 10:15, 24 August 21
Quote from: BeaglzNZ on 01:59, 24 August 21
Just wondering if you have managed to create a STL for a case for these cartridges? I have got a few PCBs and awaiting parts to assemble - any idea if there is enough clearance for a ZIF socket?
Cheers,
Antony

There's definitely not enough space for a ZIF socket. Even a standard low profile IC socket will require a hole in the lid for the IC to poke through.

Bryce.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Philippe Lardenois on 21:30, 24 August 21
There one STL on Thingverse for normal Cartridge.


quite easy to modify. Will have a look next week.


Done - the bottom is the same that is avalaible on Thingverse thanks to Wolfiem.
The top has 2 versions : Hole to seen the eeprom and change it without opening the cartridge / hole covered otherwise.

+
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Cwiiis on 20:16, 27 August 21
I took it on to design a shell that's a bit closer to the original. There are some compromises due to FDM printing limitations and laziness, so it's a little bit boxier than the original and the details aren't all 100%. Biggest/most obvious changes are that the front and back sticker recesses are marked out but not recessed as that makes them near-impossible to print well, and the sides of the cart aren't tapered. Smaller differences are that the bottom edge also isn't tapered and the grips are a little different because it's impossible to print that detail with a 0.4mm nozzle.

This should be printed with the flat surface on the print bed and with supports everywhere. They print side-by-side fine and with my personal settings, it's a bit under a 4-hour print. It's designed to be printed with a 0.4mm nozzle and 0.2mm layer height. Once support is cleared, the pieces will snap together - if you're lucky, you can also pry them apart, but that may break the clasps (done it a few times here and no breakages yet, but that surprised me). Enjoy!
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Shining on 16:10, 28 August 21
Somewhere else I've written that already.


after analyzing the oszillograms from octoate and nilquader in the past I found a solution for the reset problem with a simple rc-combination on the preset pin.
I never had any issues with a cart using this and I always use a reset-key.


Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Chinnery on 15:13, 30 August 21
I've attached my Eagle project (Sch/Brd) should anyone wish to implement Shining's reset fix. If you do and it tests well can you please repost back here? (I have no plus machine to test with)
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: TotO on 17:58, 03 December 21
Quote from: Shining on 16:10, 28 August 21
Somewhere else I've written that already.

after analyzing the oszillograms from octoate and nilquader in the past I found a solution for the reset problem with a simple rc-combination on the preset pin. I never had any issues with a cart using this and I always use a reset-key.
I have tested this schematic by curiosity, and it looks to not work at all. ;D

May be I have done something wrong...
I don't understand what does special your RC combination compared to the original schematic.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: ChrisJames on 15:14, 05 December 21
Somebody know this cartridge

https://twitter.com/anakintf/status/1459907093780217856 (https://twitter.com/anakintf/status/1459907093780217856)
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: TotO on 20:52, 05 December 21
Well... It is probably the C4CPC grandfather. ;D
Nothing official here, despite the Amstrad logo.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: gerald on 21:49, 05 December 21
Quote from: ChrisJames on 15:14, 05 December 21
Somebody know this cartridge

https://twitter.com/anakintf/status/1459907093780217856 (https://twitter.com/anakintf/status/1459907093780217856)
Looks like a cartridge with a flash instead of eprom.
The red/black wire are used to carry WEN/OEN to the cartrige PCB (these are not wired to the cartrige connector).

So it's a nice way to avoid unplugging the flash from its socket when you need to reflash it.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: ChrisJames on 23:31, 05 December 21
Quote from: TotO on 20:52, 05 December 21
Well... It is probably the C4CPC grandfather. ;D
Nothing official here, despite the Amstrad logo.
It looks something similar to what you want to do with the PLAY2CPC  8)
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: abalore on 23:54, 05 December 21
It seems easier to have a cartridge PCB with a ZIF socket for development.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: TotO on 00:10, 06 December 21
Quote from: ChrisJames on 23:31, 05 December 21
It looks something similar to what you want to do with the PLAY2CPC  8)
The Play2CPC allows to write the cartridges directly from the CPC.
It is more close to what is doing the X-MEM or the good old CTC-AY project.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: BeaglzNZ on 03:31, 11 December 21
Just wondering what thickness do you use for the PCBs? I got some done at the default thickness which is 1.6mm I think but it seems a bit too thick?
Thanks.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Bryce on 11:42, 11 December 21
1.6mm is the correct thickness. The card pins need to make good contact.


Bryce.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Curlypaul on 04:26, 27 December 21
Quote from: BeaglzNZ on 03:31, 11 December 21
Just wondering what thickness do you use for the PCBs? I got some done at the default thickness which is 1.6mm I think but it seems a bit too thick?
Thanks.


Are you willing to sell one? Looking to create a demo, and if I can't get a C4CPC, one of these would be the back up plan
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Shining on 10:55, 05 January 22
Quote from: TotO on 17:58, 03 December 21
I have tested this schematic by curiosity, and it looks to not work at all. ;D

May be I have done something wrong...
I don't understand what does special your RC combination compared to the original schematic.


Perhaps my schematic was not clear, cause I missed to describe the signal on the RC-combination:


On the original oscillogram for acid reset (https://www.cpcwiki.eu/index.php/File:ACID_Init_by_Grim.png (https://www.cpcwiki.eu/index.php/File:ACID_Init_by_Grim.png)) you will notice that after startup the sin signal has to be high. Using the original schematic from nilquader, the sin signal after reset is 50% low or high cause it does not follow the reset at all. Now instead of pulling the RC to VCC, I used the CCLR signal not only for CLK+ but also for PRE at the flip flop to force the flipflop to "1" after reset. Also I lowered the time constant for the RC-combination.


I know quite some plusses where this always works and noone reported a single problem until now.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: TotO on 12:19, 05 January 22
Hi Shining,

Please, can you show it working?
I have tested and it doesn't work for me.

Thank you.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Bryce on 14:43, 05 January 22
I use one of these all the time. It has always worked fine with any machine I tried it on.

Bryce.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: schombi on 07:53, 09 January 22
My skills in soldering a fairly poor and I have no background in electronics, but I successfully managed to build me a working Batman the Movie cartridge. Thanks for sharing this project!
(https://forum.tlienhard.com/phpBB3/download/file.php?id=12991)
What I´m still struggling with: I was always under the impression that the ACID chip was always required to use a cartridge on the GX4000 and those chips are hard to get these days. How come this project lets you decide whether to run with or without the ACID chip?
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: Bryce on 13:04, 09 January 22
Quote from: schombi on 07:53, 09 January 22
My skills in soldering a fairly poor and I have no background in electronics, but I successfully managed to build me a working Batman the Movie cartridge. Thanks for sharing this project!
(https://forum.tlienhard.com/phpBB3/download/file.php?id=12991)
What I´m still struggling with: I was always under the impression that the ACID chip was always required to use a cartridge on the GX4000 and those chips are hard to get these days. How come this project lets you decide whether to run with or without the ACID chip?

The 74HC112 is setting the appropriate signals at exactly the right time, so the CPC thinks there's a valid ACID chip on the board.

Bryce.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: schombi on 20:29, 09 January 22
Many thanks! Has this been only discovered "recently"? Seems like a pretty simple solution. I always thought a more complex workaround (e.g. a CPLD) was required.
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: pelrun on 04:38, 10 January 22
There's a flaw in the ACID design that's being exploited - the CPC signals that the input from the 'ACID' is wrong long enough before forcing a reset that you can flip the input you're supplying (via the '112) to make it happy again.
https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/acid-chip-inside/msg22291/#msg22291 (https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/acid-chip-inside/msg22291/#msg22291)
Title: Re: Amstrad GX4000 / Plus cartridge PCB
Post by: schombi on 10:33, 10 January 22
Cheers!  :)
Powered by SMFPacks Menu Editor Mod