Trailing bits after sector read / write

[dshadoff]

According to this post:
http://pcedev.blockos.org/viewtopic.php?f=5&t=98&start=10#p737

The 'read sector' routine should send 3 bits after completing a sector read (but your code doesn't do this yet). I have tested this, and it seems necessary.

In the same post, the 'write sector' routine has a slightly different end-sector sequence. It seems to read 2 bits, then send 3, then check the value of the last bit read. I haven't checked whether this is necessary though.

[dshadoff]

I have just tested the write sectors again, on a real MB128.

The 'write sectors' function does expect - after the 512 bytes have been written - two status bits to be read, followed by the three '0' trailer bits to be written (unlike the read routine which only writes the three '0' trailer bits).

Although it was a limited review of dozens (not hundreds) of sectors, the first status bit returned was always a '1', and the second always a '0'.

[dshadoff]

Also note that the status bit read after the 'boot' command (before the 3 trailer bits) is always returned as a '0'.