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Verilog implementation of the ACID chip

2,206 bytes added, 10:47, 15 April 2011
added new page for the verilog code
= Download =
* [[Media:acid.v|Verilog Code]]

= Code =

<pre>
`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company:
// Engineer: Octoate, Nilquader
// ACID Reverse engineering by nocash
//
// Create Date : 00:45:53 09/03/2010
// Design Name : amsacid
// Module Name : amsacid
// Project Name :
// Target Devices: Xilinx XC9572
// Tool versions :
// Description : Reverse engineered Amstrad 40908 "ACID" Chip
//
// Revision:
// Revision 0.05
// Additional Comments:
//
//////////////////////////////////////////////////////////////////////////////////
module amsacid(PinCLK, PinA, PinOE, PinCCLR, PinSIN);

input PinCLK;
input [7:0]PinA;
input PinOE;
input PinCCLR;

output [7:0]PinSIN;

wire PinCLK;

reg [16:0]ShiftReg = 17'h1FFFF;
wire [16:0]CmpVal;
wire [16:0]XorVal;

assign CmpVal = 17'h13596 ^ (PinA[0] ? 17'h0000c : 0)
^ (PinA[1] ? 17'h06000 : 0)
^ (PinA[2] ? 17'h000c0 : 0)
^ (PinA[3] ? 17'h00030 : 0)
^ (PinA[4] ? 17'h18000 : 0)
^ (PinA[5] ? 17'h00003 : 0)
^ (PinA[6] ? 17'h00600 : 0)
^ (PinA[7] ? 17'h01800 : 0);
assign XorVal = 17'h0C820 ^ (PinA[0] ? 17'h00004 : 0)
^ (PinA[1] ? 17'h06000 : 0)
^ (PinA[2] ? 17'h00080 : 0)
^ (PinA[3] ? 17'h00020 : 0)
^ (PinA[4] ? 17'h08000 : 0)
^ (PinA[5] ? 17'h00000 : 0)
^ (PinA[6] ? 17'h00000 : 0)
^ (PinA[7] ? 17'h00800 : 0);

always@(negedge PinCLK)
begin

if (PinCCLR) // not in reset state
begin
if (!PinOE && ((ShiftReg | 17'h00100) == CmpVal))
begin
ShiftReg <= (ShiftReg ^ XorVal) >> 1;
ShiftReg[16] <= ShiftReg[0] ^ ShiftReg[9] ^ ShiftReg[12] ^ ShiftReg[16] ^ XorVal[0]; // hier xorval mit berüchsichtigen
end
else
begin
ShiftReg <= ShiftReg >> 1;
ShiftReg[16] <= ShiftReg[0] ^ ShiftReg[9] ^ ShiftReg[12] ^ ShiftReg[16];
end
end
else
begin
ShiftReg <= 17'h1FFFF;
end
end

//assign PinSIN = ShiftReg[7:0] ^ 8'hff;
assign PinSIN = ShiftReg[7:0];
//assign PinSIN[0] = PinCLK;


endmodule
</pre>

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