I've just been studying the atom interface, and I've got a quick query..... clearly a write is split into two portions - first a byte is written and latched by IC5, then another byte is written and passed through IC4 to the hard drive's d0-d7, with IC5 feeding the hard drive's d8-d15.
A read is similar - when read, IC6 feeds the hard drive's d8-d15 to the SAM's bus, whilst the hard drive's d0-d7 is latched by IC7. A further read by the SAM then get's the latched value from IC7. My query is about the mapping of the SAM's data lines onto the hard drive's lines - it seems to be as follows: SAM (read) | 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 -----------------------------------------|------------------------ Hard drive | 15 14 13 12 11 10 9 8 | 7 6 5 4 3 2 1 0 -----------------------------------------|------------------------ SAM (write)| 7 6 5 4 3 2 1 0 |..0..1..2..3..4..5..6..7. The mapping of the hard drive's d7 - d0 is the opposite of what I would expect when writing. Is there an error for IC4's connections on the diagram, or is there some swapping of bits in software? Thanks, Andy
