With the FDC in high-density (500kbps) mode, the peak interval between
requests for data is actually 16us, not 20us, as measured on the A5000.
Also, the 18.9us should be altered for the 36MHz MEMC clock instead of
the 24MHz MEMC clock, which is an estimated 12us. (this is an over
simplification, since it takes no account of the VIDC transfer rate
for a built in mode definition).
However, as I have pointed out, the time for the ARM to load the required
byte when writing is more critical than this - it will not work if it
requests a byte and you load it 15.9us after. That is what the old
residual checking that I had in my floppy driver was supposed to catch.
NOTE: If you do exceed the required timing when writing, you will not
know about it until you try to read it. Don't forget that Linux caches
the disk contents, so simply writing and then reading won't tell you
if it's written properly. You need to close /dev/fd and eject the
disk between read and write (or call the BLKFLSBUF ioctl).
_____
|_____| ------------------------------------------------- ---+---+-
| | Russell King [EMAIL PROTECTED] --- ---
| | | | http://www.arm.linux.org.uk/~rmk/armlinux.html / / |
| +-+-+ --- -+-
/ | THE developer of ARM Linux |+| /|\
/ | | | --- |
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