3.5" floppy jumpers
pete at dunnington.plus.com
Fri Nov 28 02:57:19 CST 2008
On 28/11/2008 04:39, Curtis H. Wilbar Jr. wrote:
> Another is a TEAC FD-235HF and has jumpers for: H HO, OP, LHI, HHI,
> and a position (but no header pins) for FG.
See if Google can find you a document called 3fd0020a.pdf -- that's
TEAC's config sheeet for the whole FD235 range. There are lots of
models with different jumpers. That one is one of the dual 720K/1.44M
3xxx (old) versions.
HO determines whether it outputs a signal to tell the host controller
whether the disk is DD or HD, normally on pin 2.
HI determines whether it accepts a density select input on pin 2.
LHI and HHI are something to do with the density select input on pin 2.
They're definitely related to HI, but I seem to recall having jumpers
on all three on at least one drive. I'm pretty sure you jumper both or
neither, never just one.
I'm not sure what H on its own would be. HA tells the drive to
determine density itself, from the HD hole sensor, instead of getting it
from the host.
Sometimes there's a number after the jumper name, like for DC. DC34
means the Disk Changed signal is on pin 34, while DC2 (on a few models)
means it puts that signal on pin 2.
FG is for Frame Ground; sometimes there's a jumper or solder link to
connect it to the 0V DC supply.
> The last is a Sony MPF520-1 which has 2 rows of 3 pins... and I have
> no idea what they are for.
> I understand some abbreviations... RDY (ready), DC (disk change),
> but not MD, MM, TTL/C-MOS (assuming this is for interface logic
> levels?), and the TEAC ones I don't know at all.
MD and MM usually refer to what turns the motor on: only when asserted
with Drive Select, or any time the Motor On signal is active.
> The Sony one is a mystery, and a google search hasn't turned
> anything up... don't know if the headers are for selecting D0-D3
> only... or more than that.
Some Sony drives have jumpers to determine when they output index pulses
(only when the drive is up top speed, or always). But if you only have
a few, they're probably just the drive select jumpers.
Pete Peter Turnbull
University of York
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