DESCRIPTION OF PIN FUNCTIONS
BUFFER
QFP/
TQFP
PIN NO.
TYPE
NAME
SYMBOL
DESCRIPTION
8
nStep Pulse
nSTEP
OD48
This active low high current driver issues a low
pulse for each track-to-track movement of the
head.
17
Disk Change
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
OD48
OD48
OD48
IS
Active low open drain outputs select drives 0-
1.
nMotor On 0,1
DRVDEN0
nMTR0,1
These active low open drain outputs select
motor drives 0-1.
DRVDEN0
nWRTPRT
Indicates the drive and media selected. Refer
to configuration registers CR03, CR0B, CR1F.
14
nWrite
This active low Schmitt Trigger input senses
from the disk drive that a disk is write
protected. Any write command is ignored.
Protected
13
12
wTrack 00
nTRK00
nINDEX
IS
IS
This active low Schmitt Trigger input senses
from the disk drive that the head is positioned
over the outermost track.
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
DRVDEN1
DRVDEN 1
OD48
Indicates the drive and media selected. Refer
to configuration registers CR03, CR0B, CR1F.
SERIAL PORT INTERFACE
88
89
Receive Data 2
Transmit Data 2
RXD2/IRRX
I
Receiver serial data input for port 2. IR
Receive Data
TXD2/IRTX
O24
Transmit serial data output for port 2. IR
transmit data.
78
79
Receive Data 1
Transmit Data 1
RXD1
TXD1
I
Reciever serial data input for port 1.
Transmit serial data output for port 1.
024
8
SMSC [ SMSC CORPORATION ]
