GM82C765B Datasheet, PDF (5/36 Pages) Hynix Semiconductor – FLOPPY DISK SUBSYSTEM CONTROLLER

GM82C765B
PIN NO _{MNEMOMICSIGNAL NAME I/O}
DIP PLCC
FUNCTION
34 37
MO2 ,
DS4
MOTOR ON 2 O This HCD output, when active low, is MOTOR ON
DRIVE SELECT4 HCD enable for disk drive #2, in PC AT mode. This signal
comes from the Operations Reg. In the Base or Special
mode, this output is #4 of the four decoded Unit
Selects as specified in the device command syntax
35 38
HDL
HEAD
O This HCD output, when active low, causes the head to
LOADED
HCD be loaded against the media in the selected drive.
36 39
RWC
REDUCED
O This HCD output, when active los, causes a
RPM
WRITE
CURRENT,
HCD REDUCED WRITE CURRENT when bit density is
increased toward the inner tracks, becoming active
REVOLUTIONS
when tracks>28 are accessed. This condition is valid
PER MINUTE
for Base or Special mode, and is indicative of when
write precompensation is necessary. In the PC AT
mode, this signal will be active when CR0=1
40
DCHG
DISK
I
This ST input senses status from the drive, indicating
CHANGE
ST active low that drive door is open or that the diskette
has possibly changed since last drive selection.
37 41
WP
WRITE
I
This Schmitt Trigger (ST) input senses status from the
PROTECTED ST disk drive, indicating active low when a diskette is
WRITE PROTECTED
38 42
TR00
TRACK 00
I
This ST input senses status from disk drive indicating
ST active low when the head is positioned over the
outermost track, TRACK 00
39 43
IDX
INDEX
I
This ST input senses status from the disk drive,
ST indicating active low when the head is positioned over
the beginning of a track marked by an index hole.
40 44 VCC
+5V DC
Input power supply.
Note: N – NORMAL INPUT, OUTPUT PAD
BI – BIDIRECTIONAL I/O PAD
ST – SCHMITT TRIGGER INPUT PAD
HCD – OPEN DRAIN HIGH CURRENT DRIVE OUTPUT PAD
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