Some help formatting a 5.25" floppy Please!!

pconst168 · Jun 25, 2025

I made some progress by rewriting the formatting code by first writing it all to RAM and then reading RAM and sending to the WD.
Now I get the right sector numbers as well as many correct sectors, but there is a problem at the beginning of the track. It's not writing the beginning of the track correctly it seems.

I tried to check the CRC bytes but I do not know how to calculate them. I tried online but I don't get the right answers. Could anyone please let me know if the CRCs are correct?

Thanks a lot and sorry for the trouble.

Code:

0000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0100 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0110 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0120 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0130 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0140 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0150 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0160 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0170 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0180 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0190 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0210 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0220 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0230 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0240 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0250 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0260 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0270 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0280 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0290 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0300 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0310 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0320 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0330 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0340 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0350 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0360 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0370 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0380 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0390 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
03A0 00 00 00 00 00 00 00 00 00 0B FF FF FF FF FF FF ................
03B0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
03C0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
03D0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
03E0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
03F0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0400 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0410 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0420 FF FF FF FF FF CE 00 00 07 00 78 65 FF FF FF FF ..........xe....
0430 FF FF FF FF FF FF FF 00 00 00 00 00 00 FB E5 E5 ................
0440 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0450 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0460 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0470 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0480 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0490 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
04A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
04B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 ..............]0
04C0 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 ................
04D0 FE 00 00 08 00 68 5B FF FF FF FF FF FF FF FF FF .....h[.........
04E0 FF FF 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 ................
04F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0500 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0510 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0520 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0530 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0540 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0550 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0560 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF FF .........]0.....
0570 FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 09 00 ................
0580 5B 6A FF FF FF FF FF FF FF FF FF FF FF 00 00 00 [j..............
0590 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05E0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0600 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0610 E5 E5 E5 E5 5D 30 FF FF FF FF FF FF FF FF FF FF ....]0..........
0620 00 00 00 00 00 00 FE 00 00 0A 00 0E 39 FF FF FF ............9...
0630 FF FF FF FF FF FF FF FF 00 00 00 00 00 00 FB E5 ................
0640 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0650 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0660 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0670 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0680 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0690 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
06A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
06B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D ...............]
06C0 30 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 0...............
06D0 00 FE 00 00 0B 00 3D 08 FF FF FF FF FF FF FF FF ......=.........
06E0 FF FF FF 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 ................
06F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0700 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0710 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0720 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0730 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0740 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0750 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0760 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF ..........]0....
0770 FF FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 0C ................
0780 00 A4 9F FF FF FF FF FF FF FF FF FF FF FF 00 00 ................
0790 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07E0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0800 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0810 E5 E5 E5 E5 E5 5D 38 FF FF FF FF FF FF FF FF FF .....]8.........
0820 FF 00 00 00 00 00 00 FE 00 00 0D 00 97 AE FF FF ................
0830 FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 FB ................
0840 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0850 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0860 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0870 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0880 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0890 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
08A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
08B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
08C0 5D 30 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 ]0..............
08D0 00 00 FE 00 00 0E 00 C2 FD FF FF FF FF FF FF FF ................
08E0 FF FF FF FF 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 ................
08F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0900 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0910 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0920 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0930 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0940 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0950 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0960 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF ...........]0...
0970 FF FF FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 ................
0980 0F 00 F1 CC FF FF FF FF FF FF FF FF FF FF FF 00 ................
0990 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09E0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A00 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A10 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF FF FF FF FF ......]0........
0A20 FF FF 00 00 00 00 00 00 FE 00 00 10 00 E3 81 FF ................
0A30 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 ................
0A40 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A50 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A60 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A70 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A80 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A90 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0AA0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0AB0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0AC0 E5 5D 30 FF FF FF FF FF FF FF FF FF FF FF FF FF .]0.............
0AD0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0AE0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0AF0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B10 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B20 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B30 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B40 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B50 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B60 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B70 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B80 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B90 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BA0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BB0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BC0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BD0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BE0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BF0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C10 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C20 FF FF FF FF FF FF FF FF FF

sagor · Jun 25, 2025

At byte 425, you have a CE instead of FE. Something corrupted that byte. You are missing the 2 lower bits. That is sector 7. Everything else after that up to sector 16 looks ok.
So you still have to figure out why you are missing the index pulse. My question is, do you really need it or will the 1771 start on its own when it finds it and has the write track command in the buffer? Will just monitoring the DRQ bit be enough to start writing the track. That is, with the write track command in the register, is DRQ held high until it finds the index and then drops DRQ expecting the first byte to be written? There may be a conflict with that logic, I'm not sure. I saw this note in another datasheet for the FD1771:

In the flowchart for write track, there is a logic branch that asks if the data register is loaded and if NO, to write zeroes and set Data Lost bit. You need to check that as well, it may explain your zeroes at the start.
I assume you have the right resistor pack in the interface to the floppy drive. Usually there is one (terminating resistor pack) on the drive itself. Your signals may need pull-up resistors to ensure stable signals.

pconst168 · Jun 25, 2025

pconst168 said:

I made some progress by rewriting the formatting code by first writing it all to RAM and then reading RAM and sending to the WD.
Now I get the right sector numbers as well as many correct sectors, but there is a problem at the beginning of the track. It's not writing the beginning of the track correctly it seems.

I tried to check the CRC bytes but I do not know how to calculate them. I tried online but I don't get the right answers. Could anyone please let me know if the CRCs are correct?

Thanks a lot and sorry for the trouble.

Code:

0000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0100 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0110 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0120 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0130 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0140 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0150 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0160 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0170 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0180 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0190 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0210 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0220 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0230 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0240 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0250 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0260 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0270 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0280 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0290 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
02F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0300 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0310 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0320 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0330 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0340 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0350 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0360 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0370 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0380 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0390 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
03A0 00 00 00 00 00 00 00 00 00 0B FF FF FF FF FF FF ................
03B0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
03C0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
03D0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
03E0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
03F0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0400 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0410 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0420 FF FF FF FF FF CE 00 00 07 00 78 65 FF FF FF FF ..........xe....
0430 FF FF FF FF FF FF FF 00 00 00 00 00 00 FB E5 E5 ................
0440 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0450 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0460 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0470 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0480 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0490 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
04A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
04B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 ..............]0
04C0 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 ................
04D0 FE 00 00 08 00 68 5B FF FF FF FF FF FF FF FF FF .....h[.........
04E0 FF FF 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 ................
04F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0500 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0510 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0520 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0530 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0540 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0550 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0560 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF FF .........]0.....
0570 FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 09 00 ................
0580 5B 6A FF FF FF FF FF FF FF FF FF FF FF 00 00 00 [j..............
0590 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05E0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0600 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0610 E5 E5 E5 E5 5D 30 FF FF FF FF FF FF FF FF FF FF ....]0..........
0620 00 00 00 00 00 00 FE 00 00 0A 00 0E 39 FF FF FF ............9...
0630 FF FF FF FF FF FF FF FF 00 00 00 00 00 00 FB E5 ................
0640 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0650 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0660 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0670 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0680 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0690 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
06A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
06B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D ...............]
06C0 30 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 0...............
06D0 00 FE 00 00 0B 00 3D 08 FF FF FF FF FF FF FF FF ......=.........
06E0 FF FF FF 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 ................
06F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0700 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0710 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0720 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0730 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0740 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0750 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0760 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF ..........]0....
0770 FF FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 0C ................
0780 00 A4 9F FF FF FF FF FF FF FF FF FF FF FF 00 00 ................
0790 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07E0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
07F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0800 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0810 E5 E5 E5 E5 E5 5D 38 FF FF FF FF FF FF FF FF FF .....]8.........
0820 FF 00 00 00 00 00 00 FE 00 00 0D 00 97 AE FF FF ................
0830 FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 FB ................
0840 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0850 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0860 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0870 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0880 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0890 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
08A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
08B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
08C0 5D 30 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 ]0..............
08D0 00 00 FE 00 00 0E 00 C2 FD FF FF FF FF FF FF FF ................
08E0 FF FF FF FF 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 ................
08F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0900 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0910 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0920 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0930 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0940 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0950 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0960 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF ...........]0...
0970 FF FF FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 ................
0980 0F 00 F1 CC FF FF FF FF FF FF FF FF FF FF FF 00 ................
0990 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09E0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A00 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A10 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF FF FF FF FF ......]0........
0A20 FF FF 00 00 00 00 00 00 FE 00 00 10 00 E3 81 FF ................
0A30 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 ................
0A40 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A50 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A60 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A70 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A80 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A90 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0AA0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0AB0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0AC0 E5 5D 30 FF FF FF FF FF FF FF FF FF FF FF FF FF .]0.............
0AD0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0AE0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0AF0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B10 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B20 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B30 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B40 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B50 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B60 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B70 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B80 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B90 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BA0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BB0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BC0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BD0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BE0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BF0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C10 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C20 FF FF FF FF FF FF FF FF FF

Hey Sagor, thank you again for trying to help me with this. You are really helping me bit by bit.

I have an update.......... It feels like everyday I am 5% closer to getting it to work.

I decided to turn off one of the configuration bits that enables the "spinup sequence" for the drive. This bit makes the disc spin until 6 index pulses have passed by. I thought this would do no harm so I mostly left it on. But turning it off when I send the read track command, now I see the sectors where they should be!!
So leaving that bit on somehow is not compatible with this drive. I think the WD chip loses track of the index, or it starts the process middleway. But either way it fails with that ON.

Now I can get something that looks more like a correct track. But there are still errors in some of the bytes, and that I am still not sure why,,,

But here is an example track that is working better:

Code:

0000 0B FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0010 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0020 FF FF FF FF FF FF FF FF FC 00 00 00 00 00 03 FE ................
0030 00 00 01 00 D2 C3 FF FF FF FF FF FF FF FF FF FF ................
0040 FF 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 ................
0050 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0060 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0070 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0080 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0090 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
00A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
00B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
00C0 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF FF FF ........]0......
00D0 FF FF FF FF 00 00 00 00 00 00 FE 00 00 02 00 87 ................
00E0 90 FF FF FF FF FF FF FF FF FF FF FF 00 00 00 00 ................
00F0 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0100 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0110 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0120 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0130 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0140 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0150 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0160 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0170 E5 E5 E5 5D 30 FF FF FF FF FF FF FF FF FF FF 00 ...]0...........
0180 00 00 00 00 00 FE 00 00 03 00 B4 A1 FF FF FF FF ................
0190 FF FF FF FF FF FF FF 00 00 00 00 00 00 FB E5 E5 ................
01A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
01B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
01C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
01D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
01E0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
01F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0200 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0210 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 ..............]0
0220 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 ................
0230 FE 00 00 04 00 2D 36 FF FF FF FF FF FF FF FF FF .....-6.........
0240 FF FF 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 ................
0250 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0260 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0270 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0280 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0290 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
02A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
02B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
02C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF FF .........]0.....
02D0 FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 05 00 ................
02E0 1E 07 FF FF FF FF FF FF FF FF FF FF FF 00 00 00 ................
02F0 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0300 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0310 E5 E7 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E7 F5 ................
0320 E7 E5 E5 E5 E5 E7 E5 E7 E5 E7 E5 E5 E5 E5 E5 E7 ................
0330 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0340 E5 E5 E5 F5 F5 F5 F5 F7 F5 F5 F5 F5 F5 F5 F5 F5 ................
0350 F7 F5 F7 F5 F5 F5 F5 F5 F5 F7 F5 F5 F5 F5 F5 F7 ................
0360 F5 F7 F5 F5 F5 F5 F7 F5 F7 F5 F7 F7 F7 F7 F5 F7 ................
0370 F5 F7 F5 F7 5F 38 FF FF FF FF FF FF FF FF FF FF ...._8..........
0380 80 00 00 00 00 00 FE 00 00 06 00 4B F4 FF FF FF ...........K....
0390 FF FF FF FF FF FF FF FF 00 00 00 00 00 00 FB E5 ................
03A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
03B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
03C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
03D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
03E0 E5 F5 E5 F5 E7 E5 E5 F5 E5 E5 E5 E5 E5 E5 E5 E5 ................
03F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0400 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0410 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 FD ................
0420 B0 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 ................
0430 00 FF 00 00 07 80 78 77 FF FF FF FF FF FF FF FF ......xw........
0440 FF FF FF 80 00 00 00 00 00 FF F5 F7 F5 F7 F5 F7 ................
0450 F5 F7 F5 F7 F5 F7 F5 F7 F5 F5 E5 F5 E5 F5 E5 F7 ................
0460 E5 F7 E5 F5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0470 E5 E5 E7 E5 E7 E5 E7 E5 E7 E5 E5 E5 E5 E5 E5 E5 ................
0480 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0490 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
04A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
04B0 E5 E5 E5 E5 E5 E7 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
04C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF ..........]0....
04D0 FF FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 08 ................
04E0 00 68 5B FF FF FF FF FF FF FF FF FF FF FF 00 00 .h[.............
04F0 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0500 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0510 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0520 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0530 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0540 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0550 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0560 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0570 E5 E5 E5 E5 E5 5D 30 FF FF FF FF FF FF FF FF FF .....]0.........
0580 FF 00 00 00 00 00 00 FE 00 00 09 00 5B 6A FF FF ............[j..
0590 FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 FB ................
05A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05E0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
05F0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0600 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0610 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0620 5D 30 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 ]0..............
0630 00 00 FE 00 00 0A 00 0E 39 FF FF FF FF FF FF FF ........9.......
0640 FF FF FF FF 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 ................
0650 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0660 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0670 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0680 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0690 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
06A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
06B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
06C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF ...........]0...
06D0 FF FF FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 ................
06E0 0B 00 3D 08 FF FF FF FF FF FF FF FF FF FF FF 00 ..=.............
06F0 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0700 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0710 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0720 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0730 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0740 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0750 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0760 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0770 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF FF FF FF FF ......]0........
0780 FF FF 00 00 00 00 00 00 FE 00 00 0C 00 A4 9F FF ................
0790 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 ................
07A0 FB E5 F7 E5 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 ................
07B0 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 E5 E5 F5 E5 E5 E5 ................
07C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 F5 E5 F5 E5 F5 E5 ................
07D0 F5 E5 E5 E5 F5 E5 F5 E5 F5 E5 F5 E5 E5 E5 E5 E5 ................
07E0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 F5 E5 F5 E5 ................
07F0 F5 E5 E5 E5 E5 E5 E5 E5 E5 F5 E5 F5 E5 F5 E5 E5 ................
0800 E5 E5 E5 E5 E5 E5 F5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0810 E5 E5 E5 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 E5 E5 E5 ................
0820 E5 5D 30 FF FF FF FF FF FF FF FF FF FF 00 00 00 .]0.............
0830 00 00 00 FF 00 00 0D 00 97 AE FF FF FF FF FF FF ................
0840 FF FF FF FF FF 80 00 00 00 00 00 FB F5 E5 F5 E5 ................
0850 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 ................
0860 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 F5 E5 E5 E5 ................
0870 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0880 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0890 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
08A0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
08B0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
08C0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF ............]0..
08D0 FF FF FF FF FF FF FF FF 00 00 00 00 00 00 FE 00 ................
08E0 00 0E 00 C2 FD FF FF FF FF FF FF FF FF FF FF FF ................
08F0 00 00 00 00 00 00 FB E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0900 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0910 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0920 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0930 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0940 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0950 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0960 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0970 E5 E5 E5 E5 E5 E5 E5 5D 30 FF FF FF FF FF FF FF .......]0.......
0980 FF FF FF 00 00 00 00 00 00 FE 80 00 0F 00 F1 CC ................
0990 FF FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 ................
09A0 00 FB E5 E5 E5 E5 E5 E5 ED E7 ED E5 ED E5 ED E5 ................
09B0 ED E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09C0 ED E5 ED E5 ED E7 ED E7 ED E5 E5 E5 E5 E5 E5 E5 ................
09D0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09E0 E5 E5 E5 E5 ED E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
09F0 E5 E5 E5 E5 E5 E5 ED E7 ED E7 ED E5 ED E5 ED E7 ................
0A00 ED E7 ED E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A10 ED E7 ED E5 ED E5 ED E5 ED E5 ED E5 E5 E5 E5 E5 ................
0A20 E5 E5 5D 30 FF FF FF FF FF FF FF FF FF FF 00 00 ..]0............
0A30 00 00 00 00 FE 00 00 10 00 E2 81 FF FF FF FF FF ................
0A40 FF FF FF FF FF FF 00 00 00 00 00 00 FB E5 E5 ED ................
0A50 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A60 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A70 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A80 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0A90 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0AA0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0AB0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 ................
0AC0 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 E5 5D 30 FF .............]0.
0AD0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0AE0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0AF0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B10 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B20 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B30 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B40 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B50 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B60 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B70 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B80 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B90 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BA0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BB0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BC0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BD0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BE0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BF0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C10 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C20 FF FF FF FF FF FF FF FF FF

sagor · Jun 25, 2025

Data before first sector still has minor errors, with that FC still showing the lower 2 bits missing (again). Sector 7 has an 80 for sector length, which is invalid, and you can see all wrong data as a filler. Sector 12 at 7A0 has some wrong data again. Sector 13 at 845 has an invalid "80" instead of 00, and data is messed up again with F5 intermixed with E5. Yet, sector 14 looks ok.

I wonder if there is a timing issue with your data bus, or perhaps a chip that does not meet "spec". You seem to be getting one or 2 bit errors at random times. Not on every byte, but with random repeats. I would re-check the interface chips to the WD1771 from the CPU data bus. Or, could it be your memory access for the buffer that holds the track data before the track write? Can you examine/dump the data buffer before/after the track write to confirm the data is correct to start with.
I assume the read track duplicates the read data every time (it is identical). If so, that makes it more confusing if reads are repeatable, but write data has random bit errors. Read a track several times to verify the read data is identical, or not...
Most (except at start and that FC instead of FF) the DATA bit errors I see have an extra bit added, there is few bits dropped/missing. That could mean a chip on the data path is slow in changing the state from 1 to 0.

pconst168 · Jun 26, 2025

sagor said:
Data before first sector still has minor errors, with that FC still showing the lower 2 bits missing (again). Sector 7 has an 80 for sector length, which is invalid, and you can see all wrong data as a filler. Sector 12 at 7A0 has some wrong data again. Sector 13 at 845 has an invalid "80" instead of 00, and data is messed up again with F5 intermixed with E5. Yet, sector 14 looks ok.

I wonder if there is a timing issue with your data bus, or perhaps a chip that does not meet "spec". You seem to be getting one or 2 bit errors at random times. Not on every byte, but with random repeats. I would re-check the interface chips to the WD1771 from the CPU data bus. Or, could it be your memory access for the buffer that holds the track data before the track write? Can you examine/dump the data buffer before/after the track write to confirm the data is correct to start with.
I assume the read track duplicates the read data every time (it is identical). If so, that makes it more confusing if reads are repeatable, but write data has random bit errors. Read a track several times to verify the read data is identical, or not...
Most (except at start and that FC instead of FF) the DATA bit errors I see have an extra bit added, there is few bits dropped/missing. That could mean a chip on the data path is slow in changing the state from 1 to 0.

Hi Sagor. I think I found out what those errors were. Someone told me that I cannot use HD disks while in SD mode... And I was using HD disks..........So I changed the disk to a SD/DD type, and all those errors went away. HD disks require 600oe coercivity while SD ones is just 300oe so the magnetiation was too weak. After changing the disk it reads OK now and I can also read track and sectors. I am writing a sequence of 00 to 7F now to the data areas rather than just E5 so I can be sure the data is not just a repeat of whatever was in the data register before. There are a few remaining byte errors only at the very beginning of the track. I'm not sure what that indicates ... Do you know why that could happen and if it's normal?

Thank you again for your time and help!!

Code:

000 FB FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0010 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0020 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF CE ................
0030 00 00 01 00 D2 C3 FF FF FF FF FF FF FF FF FF FF ................
0040 FF 00 00 00 00 00 00 FB 00 01 02 03 04 05 06 07 ................
0050 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 17 ................
0060 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 ........ !"#$%&'
0070 28 29 2A 2B 2C 2D 2E 2F 30 31 32 33 34 35 36 37 ()*+,-./01234567
0080 38 39 3A 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 47 89:;<=>?@ABCDEFG
0090 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 HIJKLMNOPQRSTUVW
00A0 58 59 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67 XYZ[\]^_`abcdefg
00B0 68 69 6A 6B 6C 6D 6E 6F 70 71 72 73 74 75 76 77 hijklmnopqrstuvw
00C0 78 79 7A 7B 7C 7D 7E 7F A0 23 FF FF FF FF FF FF xyz{|}~..#......
00D0 FF FF FF FF 00 00 00 00 00 00 FE 00 00 02 00 87 ................
00E0 90 FF FF FF FF FF FF FF FF FF FF FF 00 00 00 00 ................
00F0 00 00 FB 00 01 02 03 04 05 06 07 08 09 0A 0B 0C ................
0100 0D 0E 0F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C ................
0110 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C ... !"#$%&'()*+,
0120 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C -./0123456789:;<
0130 3D 3E 3F 40 41 42 43 44 45 46 47 48 49 4A 4B 4C =>?@ABCDEFGHIJKL
0140 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A 5B 5C MNOPQRSTUVWXYZ[\
0150 5D 5E 5F 60 61 62 63 64 65 66 67 68 69 6A 6B 6C ]^_`abcdefghijkl
0160 6D 6E 6F 70 71 72 73 74 75 76 77 78 79 7A 7B 7C mnopqrstuvwxyz{|
0170 7D 7E 7F A0 23 FF FF FF FF FF FF FF FF FF FF 00 }~..#...........
0180 00 00 00 00 00 FE 00 00 03 00 B4 A1 FF FF FF FF ................
0190 FF FF FF FF FF FF FF 00 00 00 00 00 00 FB 00 01 ................
01A0 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 ................
01B0 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 .............. !
01C0 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F 30 31 "#$%&'()*+,-./01
01D0 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 40 41 23456789:;<=>?@A
01E0 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 BCDEFGHIJKLMNOPQ
01F0 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F 60 61 RSTUVWXYZ[\]^_`a
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0210 72 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F A0 23 rstuvwxyz{|}~..#
0220 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 ................
0230 FE 00 00 04 00 2D 36 FF FF FF FF FF FF FF FF FF .....-6.........
0240 FF FF 00 00 00 00 00 00 FB 00 01 02 03 04 05 06 ................
0250 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 ................
0260 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 ......... !"#$%&
0270 27 28 29 2A 2B 2C 2D 2E 2F 30 31 32 33 34 35 36 '()*+,-./0123456
0280 37 38 39 3A 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 789:;<=>?@ABCDEF
0290 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 GHIJKLMNOPQRSTUV
02A0 57 58 59 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 WXYZ[\]^_`abcdef
02B0 67 68 69 6A 6B 6C 6D 6E 6F 70 71 72 73 74 75 76 ghijklmnopqrstuv
02C0 77 78 79 7A 7B 7C 7D 7E 7F A0 23 FF FF FF FF FF wxyz{|}~..#.....
02D0 FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 05 00 ................
02E0 1E 07 FF FF FF FF FF FF FF FF FF FF FF 00 00 00 ................
02F0 00 00 00 FB 00 01 02 03 04 05 06 07 08 09 0A 0B ................
0300 0C 0D 0E 0F 10 11 12 13 14 15 16 17 18 19 1A 1B ................
0310 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B .... !"#$%&'()*+
0320 2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 3A 3B ,-./0123456789:;
0330 3C 3D 3E 3F 40 41 42 43 44 45 46 47 48 49 4A 4B <=>?@ABCDEFGHIJK
0340 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A 5B LMNOPQRSTUVWXYZ[
0350 5C 5D 5E 5F 60 61 62 63 64 65 66 67 68 69 6A 6B \]^_`abcdefghijk
0360 6C 6D 6E 6F 70 71 72 73 74 75 76 77 78 79 7A 7B lmnopqrstuvwxyz{
0370 7C 7D 7E 7F A0 23 FF FF FF FF FF FF FF FF FF FF |}~..#..........
0380 00 00 00 00 00 00 FE 00 00 06 00 4B 54 FF FF FF ...........KT...
0390 FF FF FF FF FF FF FF FF 00 00 00 00 00 00 FB 00 ................
03A0 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 ................
03B0 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 ...............
03C0 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F 30 !"#$%&'()*+,-./0
03D0 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 40 123456789:;<=>?@
03E0 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 ABCDEFGHIJKLMNOP
03F0 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F 60 QRSTUVWXYZ[\]^_`
0400 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F 70 abcdefghijklmnop
0410 71 72 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F A0 qrstuvwxyz{|}~..
0420 23 FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 #...............
0430 00 FE 00 00 07 00 78 65 FF FF FF FF FF FF FF FF ......xe........
0440 FF FF FF 00 00 00 00 00 00 FB 00 01 02 03 04 05 ................
0450 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 ................
0460 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 .......... !"#$%
0470 26 27 28 29 2A 2B 2C 2D 2E 2F 30 31 32 33 34 35 &'()*+,-./012345
0480 36 37 38 39 3A 3B 3C 3D 3E 3F 40 41 42 43 44 45 6789:;<=>?@ABCDE
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04B0 66 67 68 69 6A 6B 6C 6D 6E 6F 70 71 72 73 74 75 fghijklmnopqrstu
04C0 76 77 78 79 7A 7B 7C 7D 7E 7F A0 23 FF FF FF FF vwxyz{|}~..#....
04D0 FF FF FF FF FF FF 00 00 00 00 00 00 FE 00 00 08 ................
04E0 00 68 5B FF FF FF FF FF FF FF FF FF FF FF 00 00 .h[.............
04F0 00 00 00 00 FB 00 01 02 03 04 05 06 07 08 09 0A ................
0500 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 17 18 19 1A ................
0510 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A ..... !"#$%&'()*
0520 2B 2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 3A +,-./0123456789:
0530 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 47 48 49 4A ;<=>?@ABCDEFGHIJ
0540 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A KLMNOPQRSTUVWXYZ
0550 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67 68 69 6A [\]^_`abcdefghij
0560 6B 6C 6D 6E 6F 70 71 72 73 74 75 76 77 78 79 7A klmnopqrstuvwxyz
0570 7B 7C 7D 7E 7F A0 23 FF FF FF FF FF FF FF FF FF {|}~..#.........
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0590 FF FF FF FF FF FF FF FF FF 00 00 00 00 00 00 FB ................
05A0 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ................
05B0 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F ................
05C0 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F  !"#$%&'()*+,-./
05D0 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 0123456789:;<=>?
05E0 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F @ABCDEFGHIJKLMNO
05F0 50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F PQRSTUVWXYZ[\]^_
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0610 70 71 72 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F pqrstuvwxyz{|}~.
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0650 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 ................
0660 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 ........... !"#$
0670 25 26 27 28 29 2A 2B 2C 2D 2E 2F 30 31 32 33 34 %&'()*+,-./01234
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06E0 0B 00 3D 08 FF FF FF FF FF FF FF FF FF FF FF 00 ..=.............
06F0 00 00 00 00 00 FB 00 01 02 03 04 05 06 07 08 09 ................
0700 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 17 18 19 ................
0710 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 ...... !"#$%&'()
0720 2A 2B 2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 *+,-./0123456789
0730 3A 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 47 48 49 :;<=>?@ABCDEFGHI
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0750 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67 68 69 Z[\]^_`abcdefghi
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0770 7A 7B 7C 7D 7E 7F A0 23 FF FF FF FF FF FF FF FF z{|}~..#........
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07A0 FB 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E ................
07B0 0F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E ................
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07D0 2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E /0123456789:;<=>
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07F0 4F 50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E OPQRSTUVWXYZ[\]^
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0840 FF FF FF FF FF 00 00 00 00 00 00 FB 00 01 02 03 ................
0850 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 ................
0860 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 ............ !"#
0870 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F 30 31 32 33 $%&'()*+,-./0123
0880 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 40 41 42 43 456789:;<=>?@ABC
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08F0 00 00 00 00 00 00 FB 00 01 02 03 04 05 06 07 08 ................
0900 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 17 18 ................
0910 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 ....... !"#$%&'(
0920 29 2A 2B 2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 )*+,-./012345678
0930 39 3A 3B 3C 3D 3E 3F 40 41 42 43 44 45 46 47 48 9:;<=>?@ABCDEFGH
0940 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 IJKLMNOPQRSTUVWX
0950 59 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67 68 YZ[\]^_`abcdefgh
0960 69 6A 6B 6C 6D 6E 6F 70 71 72 73 74 75 76 77 78 ijklmnopqrstuvwx
0970 79 7A 7B 7C 7D 7E 7F A0 23 FF FF FF FF FF FF FF yz{|}~..#.......
0980 FF FF FF 00 00 00 00 00 00 FE 00 00 0F 00 F1 CC ................
0990 FF FF FF FF FF FF FF FF FF FF FF 00 00 00 00 00 ................
09A0 00 FB 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D ................
09B0 0E 0F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D ................
09C0 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D .. !"#$%&'()*+,-
09D0 2E 2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D ./0123456789:;<=
09E0 3E 3F 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D >?@ABCDEFGHIJKLM
09F0 4E 4F 50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D NOPQRSTUVWXYZ[\]
0A00 5E 5F 60 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D ^_`abcdefghijklm
0A10 6E 6F 70 71 72 73 74 75 76 77 78 79 7A 7B 7C 7D nopqrstuvwxyz{|}
0A20 7E 7F A0 23 FF FF FF FF FF FF FF FF FF FF 00 00 ~..#............
0A30 00 00 00 00 FE 00 00 10 00 E2 81 FF FF FF FF FF ................
0A40 FF FF FF FF FF FF 00 00 00 00 00 00 FB 00 01 02 ................
0A50 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 ................
0A60 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 ............. !"
0A70 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F 30 31 32 #$%&'()*+,-./012
0A80 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 40 41 42 3456789:;<=>?@AB
0A90 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 CDEFGHIJKLMNOPQR
0AA0 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F 60 61 62 STUVWXYZ[\]^_`ab
0AB0 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F 70 71 72 cdefghijklmnopqr
0AC0 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F A0 23 FF stuvwxyz{|}~..#.
0AD0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0AE0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0AF0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B10 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B20 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B30 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B40 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B50 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B60 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B70 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B80 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0B90 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BA0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BB0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BC0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BD0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BE0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0BF0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C10 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C20 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C30 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C40 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C50 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C60 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................
0C70 FF FF FF FF FF FF FF FF FF FF                                   ..........

ci139 · Jun 26, 2025

(i haven't folloed the discussion tightly)
some other issues may arise from https://en.wikipedia.org/wiki/Bad_sector
(i have only used specialized PC utils to mess around DOS FDD/HDD drives LBA/boot ... long ago)

back at the old days you opened the disk (floppy) window cover , rotated the disk , checking for dust and debris from both sides and blew them off when detected by dry air

sagor · Jun 26, 2025

Errors at just the beginning suggest setup code may have some flaws. The first byte should be correct, an FF. Maybe check that you are storing the first byte into the data register as quickly as you can, right after the write track command (verify any required delays). I think you can write the first byte into the data register right away. You only need the 64us delay after command to read back the status, not for filling the data register, I think?
The final first filler FF is a CE, again an error. Since these errors show up in the first part of the track, before the repeating/loop sequence, suggests something with the code before you enter the loop to fill the 16 sectors. The code for filling the 16 sectors seems to be ok.

pconst168 · Jun 26, 2025

sagor said:
Errors at just the beginning suggest setup code may have some flaws. The first byte should be correct, an FF. Maybe check that you are storing the first byte into the data register as quickly as you can, right after the write track command (verify any required delays). I think you can write the first byte into the data register right away. You only need the 64us delay after command to read back the status, not for filling the data register, I think?
The final first filler FF is a CE, again an error. Since these errors show up in the first part of the track, before the repeating/loop sequence, suggests something with the code before you enter the loop to fill the 16 sectors. The code for filling the 16 sectors seems to be ok.

I think you are absolutely right. At the beginning of the code right after the command, I have a small delay of about 64us... Because I can't check for the DRQ flag before that time... Even if I write the first byte right after, I still need to wait 64us to check DRQ again.......... I actually decreased the delay a bit to experiment and maybe that's why...I'll play with the delay a bit to see if that fixes it.... Thanks a lot again!!

sagor · Jun 26, 2025

I think as soon as you set the write track command, the DRQ bit is set immediately to accept the first character. Doing the math, each character takes about 64uS to write out anyway. No harm in trying to write the first data byte into the data register right after the write track command is issued. Then wait the 64uS to read back the status and send next byte when DRQ is asking for it.
I've seen one delay comment that it can be as short as 48us to read the "Busy" bit (status bit 0), but 64uS for the rest of the status bits to be set, including DRQ (bit 1 in status register)

pconst168 · Jun 27, 2025

sagor said:
I think as soon as you set the write track command, the DRQ bit is set immediately to accept the first character. Doing the math, each character takes about 64uS to write out anyway. No harm in trying to write the first data byte into the data register right after the write track command is issued. Then wait the 64uS to read back the status and send next byte when DRQ is asking for it.
I've seen one delay comment that it can be as short as 48us to read the "Busy" bit (status bit 0), but 64uS for the rest of the status bits to be set, including DRQ (bit 1 in status register)

Hi Sagor. I tried that, but have the same result. Very odd. Also if I use the write sector command, then it messes up all the synchronization bytes, when I read the entire track back to inspect. But the strange thing is that if I use read sector it can find the sectors and read them back without errors. Totally crazy. The data itself is never corrupted though, only the gaps and ID fields have a few different bytes, but they seem constant and do not change.... I will try my other drive to see if I get the same result but I suspect so... But the write track command itself perfectly writes everything. Its just the write sector command that messes up the headers... What do you think is happening?

sagor · Jun 27, 2025

If the data is good, but sector/track data is messed up, it points to your code again, or how you are handshaking with the controller. The controller is reading and writing the data fields properly. Try experimenting with different bits in control/command. Maybe head settling is an issue? Look at the flowcharts in the data sheet and make sure you are following the same flow/logic.

pconst168 · Jun 28, 2025

sagor said:
If the data is good, but sector/track data is messed up, it points to your code again, or how you are handshaking with the controller. The controller is reading and writing the data fields properly. Try experimenting with different bits in control/command. Maybe head settling is an issue? Look at the flowcharts in the data sheet and make sure you are following the same flow/logic.

It might have to do with my CPUs read timing which is 200ns. The WD released data 200ns max after CS goes down, and typical is 100ns, but I think it might have a problem there... I've tried all possible settings but still same results. I tried different drives as well. ID marks such as FE and FB become CE and CB when I write a single sector, but when I write track for formatting they are all perfect...

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