there might be a chance in hell for you guys
😉
Ive always wondered what the data if any was out there and from snooping the CD data bus it seems to be just mode 2 sector data with a repeating pattern that results in the same EFM pattern that gives it that 'barcode' look.
This is what the modchip does is insert this fake sector data when it tells the pickup sled to move out there.
heres some data:
Code:
actaul "ring" data from a game:
0000: 00 FF FF FF-FF FF FF FF-FF FF FF 00-71 C0 71 62 ............q.qb
0010: 00 28 28 1E-80 08 48 06-59 59 59 59-59 59 59 59 .((...H.YYYYYYYY
0020: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
0030: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
0040: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
0050: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
0060: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
0070: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
...
00B0: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
00C0: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
00D0: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
00E0: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
00F0: 59 59 59 59-59 59 59 59-59 59 59 59-59 59 59 59 YYYYYYYYYYYYYYYY
0100: 59 59 59 59-59 59 59 59-59 59 59 59-72 DD E5 99 YYYYYYYYYYYYr...
descrambled:
0000: 00 FF FF FF-FF FF FF FF-FF FF FF 00-70 40 71 02 ............p@q.
0010: 00 00 28 00-00 00 28 00-F1 5B A7 D8-D9 39 39 71 ..(...(..[...99q
0020: 71 47 C7 D1-31 3F F7 F3-A5 26 58 B9-59 11 59 6F qG..1?...&X.Y.Yo
0030: D9 4F B9 57-91 5D 0F DA-27 B8 B9 11-11 6F EF CF .O.W.]..'....o..
0040: AF B7 9F 95-0B 8C A4 C6-58 F1 59 27-D9 79 39 41 ........X.Y'.y9A
0050: 71 53 C7 DE-71 3B C7 F0-F1 27 A7 F9-19 21 69 7B qS..q;...'...!i{
0060: CD 40 F6 13-A5 6E 58 8F-D9 07 B9 61-11 4B EF D4 .@...nX....a.K..
0070: EF BC EF 92-6F 8E 0F 87-E7 81 29 03-FD 62 62 0A ....o.....)..bb.
0080: 0A 24 A4 B8-D8 D1 39 3F-F1 73 A7 C6-59 31 59 77 .$....9?.s..Y1Yw
...
0050: 79 52 01 5E-23 DB FA 78-E0 81 2B 83-FC C2 62 72 yR.^#..x..+...br
0060: 0A 06 24 A1-78 DB C1 38-F3 F1 26 67-F9 49 21 55 ..$.x..8..&g.I!U
0070: 7B DC 80 FA-43 A0 92 5B-8E 18 C7 E9-31 2D 77 FE {...C..[....1-w.
0080: 05 23 E0 BA-6B 90 8C CF-86 77 81 45-03 D0 A2 7F .#..k....w.E...⌂
0090: 9A 03 88 A2-45 1A 10 A8-AF 9D 1F 8A-00 00 00 00 ....E...........
start of modchip data:
0000: 00 FF FF FF-FF FF FF FF-FF FF FF 00-71 82 02 62 ............q..b
0010: 00 28 28 1E-80 08 48 06-A0 66 A0 66-A8 59 A8 59 .((...H..f.f.Y.Y
0020: A8 59 A8 59-A8 59 A8 59-A8 59 A8 59-A8 59 A8 59 .Y.Y.Y.Y.Y.Y.Y.Y
.... repeats, ends with:
0020: A8 59 A8 59-A8 59 A8 59-A8 59 A8 59-A8 59 A8 59 .Y.Y.Y.Y.Y.Y.Y.Y
0030: A8 59 A8 59-A8 59 A8 59-A8 59 A8 59-72 DD E5 99 .Y.Y.Y.Y.Y.Yr...
descrambled:
0000: 00 FF FF FF-FF FF FF FF-FF FF FF 00-70 02 02 02 ............p...
0010: 00 00 28 00-00 00 28 00-08 64 5E E7-28 39 C8 71 ..(...(..d^.(9.q
0020: 80 47 36 D1-C0 3F 06 F3-54 26 A9 B9-A8 11 A8 6F .G6..?..T&.....o
ive noticed that the modchip generates some default MSF times where it will start at 70:02:00 and increment the count until the saturn doesnt request any more.
Im willing to take a gander that you could probably take some game image and tack on some mode 2 sectors in the format above till it reaches out to 80:00:00 or how ever far you can get
it to cover the edge
where the sled stops and have it pass the the ring check.
Im not going to try to burn some CD's myself but ill provide the info of the data thats out there. I just wanted to add some hard data to thread bucket since some cd burning expert out there might make some use of it.
take note of the scrambled and descrambled differnce, seem that all CD drives do the actual scrambling of data mode 1,2 type sectors internally to the drive. i.e. when you read it descrambles it and when you write it scrambles it internally. the ecma docs describe the algorithm.
Ive figured out a lot of how the modchip works and the protocol.Ill see if i can dig up the old homebrew modchip thread or make a new one and put some more info there.
