Enigma Variations
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info by Netraider <netraider@mail.pt>

Found on: 
-Defenders of the Earth 
-Count Duckula 
-Hong Kong Phooey 
-Postman Pat 
-Postman Pat 2 
-Sooty and Sweep 
-Thomas the Tank Engine 
-Slug 
-Father Christmas 
...and possibly more 

Low bit pulsewidth range: $00-$2D 
From TAP(s): $22 

High bit pulsewidth range:$2E-$6D 
From TAP(s): $42 

Threshold: $2D (TAP byte), $168 (360) clock cycles
Endianess: MSbF 

Lead in bytes (block start area): $40(multiple), $5a(x1), main data 
Lead in length (min.): 1 (byte $40) 
From TAP(s): 768 (byte $40) 

Blocks: 
First block is loaded at $0800, $0900 or $0c00 depending on game and is $0200 bytes long. 
Number and addresses of blocks varies according to game. 

Block checksums:none 

Additional information: 
First block start and end addresses are hard coded in main loader. 
Execution is then passed to this first block that sets following block addresses and 
reuses main load routine. 
Start block address is always set at ($0060) (low byte) and ($0061) (high byte)
End block address is always set at A register (low byte) and Y register (high byte). Then main load routine is invoked, and as first thing it moves end address in ($0062) (low byte) and ($0063) (high byte)