Commodore 64: Firebird Tape loader

@DrWatson

Published in 

C64 tape formats

 · 3 years ago

Two types are found so far, the only difference is thresholds.

T1 used on...

• Denarius
• Pitfall
• River Raid
• Zenji

T2 used on...

• Black Lamp
• Druid 2
• Sidewize
• Micro Rhythm
• Scary Monsters

------------------

T1 Threshold = tap byte $62 ($320 clock cycles)
Bit 0 : $44
Bit 1 : $7E

T2 Threshold = tap byte $52 ($29A ms)
Bit 0 : $45
Bit 1 : $65

Endianess : LSbF
Pilot byte : $02 (*254)
Sync : $52,$42.

Then...

2 bytes : Load Address (LSBF).
2 bytes : End Address (LSBF).
n bytes : Data
1 byte : XOR checksum of all n Data bytes.