DESCRIPTION OF PIN FUNCTIONS
PIN NO.
7
NAME
nDirection
Control
SYMBOL
nDIR
BUFFER
TYPE
OD48
DESCRIPTION
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.
This active low high current driver issues a
low pulse for each track-to-track movement
of the head.
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.
Active low open drain outputs select drives
0-1. Refer to Note 2.
Active low open drain output selects drives
2. Refer to Note 2.
In non-ECP mode: Active low open drain
output selects drive 3. Refer to Note 2.
This bit is used to indicate the direction of
the Parallel Port data bus. 0 = output/write
1 = input/read
In non-ECP mode: Active low open drain
output selects drive 3. Refer to Note 2.
In ECP Mode, this pin is the A10 address
input.
These active low open drain outputs select
motor drives 0-1. Refer to Note 1.
Motor On 2: Refer to Note 1.
In ECP Mode, nMTR2 is the Parallel Port
DMA Acknowledge input. Active Low.
Motor On 3: Refer to Note 1.
In ECP Mode, MTR3 is the Parallel Port
DMA Request output. Active High.
8
nStep Pulse
nSTEP
OD48
17
nDisk Change
nDSKCHG
IS
4,3
98
nDrive Select
O,1
nDrive Select 2
nDS0,1
nDS2
OD48
OD48
nDrive Select 3
nDS3
OD48
PDIR
PDIR
O4
97
nDrive Select 3
nDS3
0D48
I/O Address 10
2,5
96
nMotor On 0,1
nMotor On 2
A10
nMTR0,1
nMTR2
nPDACK
I
OD48
OD48
I
OD48
O24
99
nMotor On 3
nMTR3
PDRQ
8
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