Posted By
Gaia
on 2007-07-02
14:53:01
|  Re: CSW Viewer
Here's a C array that documents it (source is worth a thousand words  ):
unsigned char tapHeader[] = {
'C','1','6','-','T','A','P','E','-','R','A','W',
0x02, // version -> 1 - whole wave 2 - halfwave (C16/+4 specific)
0x02, // 0 - C64, 1 - VIC20, 2 - C16/+4
0x00, // Video standard ( 0= PAL, 1 =NTSC, 2 = NTSC2
0x00, // empty
// data length (4 byte) file size
// data
};
"Half-wave" means that by one TAP byte we measure the length of one half of a square wave pulse, and the initial phase is "low" (for the same C64 TAP you would store the sum of the two subsequenting bytes on one TAP byte). While the C64 tape input is edge triggered (IIRC) the plus/4 does not have this and many custom tape loaders invert the phase of the tape pulse (probably incidentally).
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