DESCRIPTION OF PIN FUNCTIONS
BUFFER
QFP/
TQFP
PIN NO.
TYPE
NAME
Direction
SYMBOL
DESCRIPTION
7
nDIR
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.
OD48
Control
8
nStep Pulse
Disk Change
nSTEP
This active low high current driver issues a
low pulse for each track-to-track movement
of the head.
OD48
17
nDSKCHG
IS
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.
4,3
2,5
1
nDrive Select
O,1
nDS0,1
Active low open drain outputs select drives
0-1.
OD48
OD48
OD48
nMotor On 0,1
nMTR0,1
DRVDEN0
These active low open drain outputs select
motor drives 0-1.
DRVDEN0
Indicates the drive and media selected.
Refer to configuration registers CR03,
CR0B, CR1F.
14
13
12
nWrite
nWRTPRT
nTRK00
IS
IS
IS
This active low Schmitt Trigger input senses
from the disk drive that a disk is write
protected. Any write command is ignored.
Protected
wTrack 00
This active low Schmitt Trigger input senses
from the disk drive that the head is
positioned over the outermost track.
nIndex
nINDEX
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.
18
88
DRVDEN1
DRVDEN 1
Indicates the drive and media selected.
Refer to configuration registers CR03,
CR0B, CR1F.
OD48
SERIAL PORT INTERFACE
RXD2/IRRX Receiver serial data input for port 2. IR
Receive Data
Receive Data 2
I
8
SMSC [ SMSC CORPORATION ]
