Nov 012014
 

After years of inactivity I decided to release two old project, which I started to work on in 2010, publicly on my GitHub account. I have not produced any prototypes yet, so they are currently more a draft. Both projects use a flash EPROM to store the data in the cartridge. The first one is a simple Amstrad Plus / Amstrad GX4000 cartridge, which can be equipped with an original ACID protection chip or with a Xilinx XC9536 CPLD for ACID emulation (you can read more about the emulation here).

SimpleCartridge

The second project is the design of a flash cartridge, which can be programmed on a PC via USB and used in a Amstrad Plus / Amstrad GX4000. You can read more about the design in the README.md.

flash-cartridge

Maybe someone with more time is interested to take over the projects, otherwise I will work on them every now and then…

Sep 102012
 

Impact and Revival released a new demo for the Amstrad Plus computers called Revival’n Impact Coop. You can download it from Pouet.net (don’t forget to vote). It features two parts coded by Ast and F-Key, with graphics by CeD and musics by Shap and Tao:

Revival’n Impact Coop–Part 1
Revival’n Impact Coop–Part 2
Apr 152011
 

Nilquader and I decided to release our Verilog code (based on Nocash’s decryption of the algorithm) to “emulate” the ACID protection chip of the Amstrad Plus. So, you can now find it in the ACID article of the CPCWiki and right here in this posting:

Selec All Code:
1
 

But this isn’t everything about the ACID. We also found a timing problem during the investigation with a logic analyzer, which you can see here:

ACID initialisation by Grim

ACID initialisation (by Grim)

You will find glitches on the /CCLR line which show that the SIN contact should be changed… All in all it is possible to use a fast flip-flop to change the SIN signal when such a glitch occurs (see picture below).

Flip flop for ACID replacement

Flip flop for ACID replacement

You see, this is a very simple schematic, but it isn’t much cheaper than a CPLD, which emulates the full ACID and it comes with a disadvantage: it won’t work with a reset, so you always have to switch the CPC off and on again.

So, have fun with it – maybe Bryce will change his cartridge design and support this solution in the future :-).

Feb 022011
 

Bryce announced the MITM (man-in-the-middle) cartridge adapter, which sits between a Plus cartridge and the Plus. With this adapter, you just need an original cartridge with an ACID protection chip which is directly connected to the CPC, but it will read the contents of the EPROM on the adapter. Maybe you know the same principle from playing Super Nintendo games from foreign countries – they used such an adapter to bypass the protection chip, too.

You can find an article about the adapter in the CPC Wiki. The schematics and layout will follow soon.

MITM3

Dec 112010
 

Bryce finished another hardware project, this time for the Amstrad Plus series. It is a multi cartridge, which contains a 512 KB EPROM or Flash-ROM on which you can place 4 128 KB ROMs. You can use the DIP switches on the cartridge to select which of the four ROMs shall be used by the CPC. As always you can find more information about the cartridge and the board layout in the Multi Cartridge article in the CPC Wiki. The project can be discussed here.

NOTE: You will still need a ACID protection chip in this cartridge.

Multi_Cartridge

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