Commodore 64: New Ocean Tape - Format 1 loader

@DrWatson

Published in 

C64 tape formats

 · 23 May 2021

Found on...

• The Addams Family
• Adidas Soccer
• Cool World
• Hook
• Hudson Hawk
• Midnight Resistance
• SlySpy
• WWF Wrestlemania

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It's a Freeload clone with an additional byte (File ID) in the header.

2 pulsewidth sets have been found so far:

T1...

• Bit 0 : $22
• Bit 1 : $42

T2...

• Bit 0 : $35
• Bit 1 : $65

Endianess: MSbF
Pilot byte : $40 (*128)
Sync : $5A

Then...

1 byte : File ID, usually ignored.
2 bytes : Load address (LSBF).
2 bytes : End address (LSBF).
n bytes : Data.
1 byte : Checksum (0 XOR all data bytes).

Trailer : 1 longer pulse (eg. $65) or 8 bits (various combinations were found) + 1 longer pulse (type 2).