GM82C803CN Datasheet, PDF (4/84 Pages) List of Unclassifed Manufacturers – 2.88 MB FDC/ Dual UARTs with FIFO/PIO(EPP/ ECP)/ IDE Interface/ S-IR/ PnP

GM82C803CN
(Continued)
PIN NO. PIN
NAME
1 DRVD-
EN0
2, 5 ^MTR0,
MTR1
3, 4 _DS1,
DS0
7
DIR
BUFFER
TYPE
DESCRIPTION
2) FLOPPY DISK INTERFACE
Out
Indicates the drive and media selected.
Out
Motor On 0,1 pins. These active low open drain outputs select
motor drives 0-1.
Out
Drive Select pin. Active low open drain outputs select drives 0-1.
Out
Direction Control pin. This high current low active output
determines the direction of the head movement. A logic 1 on this
pin means outward motion, while a logic 0 means inward motion.
8
STEP
Out
Step Pulse pin. This active low high current driver issues a low
pulse for each track-to-track movement of the head
9
WDATA
Out
Write Data pin. This active low high current driver provides the
encoded data to the disk drive. Each falling edge causes a flux
transition on the media.
10 WGATE
Out
Write Gate pin. This active low high current driver allows current
to flow through the write head. It becomes active just prior to
writing to the diskette.
11 _HDSEL
Out
Head Select pin. This high current output selects the floppy disk
side for reading or writing. A logic 1 on this pin means side 0 will
be accessed, while a logic 0 means side 1 will be accessed.
12 _INDEX
In
13 ^TRK00
In
14 WRTPRT In
16 RDATA
In
17
DSKCHG
In
18 DRVDEN1 Out
This active low Schmitt Trigger input senses from the disk drive
that the head is positioned over the beginning of a track, as
marked by an index hole.
This active low Schmitt Trigger input senses from the disk drive
that the head is positioned over the outermost track.
Write Protected pin. This active low Schmitt Trigger input senses
from the disk drive that a disk is write protected. Any write
command is ignored.
Read Disk Data pin. Raw serial bit stream from the disk drive,
low active. Each falling edge represents a flux transition of the
encoded data.
Disk Change pin. This input senses that the drive door is open or
that the diskette has possibly been changed since the last drive
selection. This input is inverted and read via bit 7 of I/O address
3F7H.
Indicates the drive and media selected.