Not much done today, but got and hour and a half in this evening. PIC code has now been modified to scan the whole disk, pretty much as follows: Select Drive Motor On Seek to Track Zero Select Side 0 Wait 250ms Select Side 1 Wait 250ms Step head ...and...
Managed to get half an hour in here. Making the code a bit more analytical. It now tells me if a SYNC word was found mid-sector and also reports how many non-sector bytes were discarded before a sync work was found. It's looking exactly as I expected: Sync Marker found**...
Well not a whole heap done today as we had a rare glimpse of the sun. The checksum checking is done & I've created a C# struct that represents all the non-Sync parts of a sector: [StructLayout(LayoutKind.Sequential, Size = 540, Pack = 1)] private struct AmigaSector { public byte DiskFormat,...
Last night I changed the PushBit() routine. After a Sync marker is found it now builds an array of bytes filled with MFM data, up to a maximum of 1080 bytes. This is 4 bytes of the data above, 16 bytes sector label, 4 bytes header checksum, 4 bytes data...
Further analysis of the MFM data. I have modified the PushBit code to pull out data bits and ignore clock bits once the sync marker has been found. The first 32 actual bits on mt first break point looks like this: 0xF012F010 According to RKRM: Devices page 572 after the...
Since getting my first Amiga 500 in the late 80s I was always interested in Amiga copy protection and disk reading/recording in general. Around 1990 I got myself a copy of "The Principles of Computer Hardware" by Alan Clements (ISBN 0-19-853703-4). A pretty geeky book for a 15 year old...