Action Replay cartridge loader ============================== info by Fabrizio Gennari Used by the Action Replay cartridge to save freezed games. Encoding: --------- In the pilot tone, sync sequence and first bytes of header, pulses are like this: Threshold: $1D0 (464) clock cycles Bit 0: TAP byte $23 Bit 1: TAP byte $53 Data Endianess: LEAST Significant bit First Lead-In : a stream of 1's, typically about 2048 of them, followed by a single 0 bit Sync sequence: $52, $42 Structure: ---------- 00-01 Complement of length of data (High, Low byte) 02-03 Start Address of data (High, Low byte) 04 Checksum (XOR of all data bytes) 05 discarded (typically $00) 06 Low byte of threshold for data bytes 07 discarded (typically $00) 08 Data bytes To calculate the number of data bytes, do 65536-complement of length. To calculate threshold for data bytes, do $100+low byte. There are two possibilities for the threshold: $1D0 (in that case, following pulses are identical to previous ones: this is the case of Turbo backup) and $111 (in that case, pulses are TAP bytes $13 for 0 and $2B for 1: that is the case of Superturbo backup)