9 Nov
1999
9 Nov
'99
11:18 p.m.
Like I said several posts back, transferring a byte
every 16 microseconds
on a sub 1 MHz processor is tricky.
My experience, plan for a worst case of a byte every 13 microseconds, that
gives a bit more room. Doing that with a 6809 (and many others) is
difficult without DMA hardware.
Of course 1.44 3.5" floppy drives can be used at 720k (or pushed to 780k)
without incurring the data rate probles as that would be 27uS worst case.
That would allow common drives and media with standard 5.25" DD rates.
for some systems this is a drop in mod or at most a matter of informing
the driver that there are 80 cylinders available if it was written for
40track (cylinder) 5.25" drives.
Allison