Interface Lines; Input Signals - NEC FD1165 Maintenance Manual

3.2.3 Interface Lines
The interface lines for the FDl165 are shown in Figure 3-2.
The even-numbered lines (2 through 50) are signal lines.
The odd-numbered lines (1 through 49) are grounds. The
lines are named for the input or output signals that they
carry.
CONTROLLER
SIGNAL NAME
PIN
NUMBER
DISK
DRIVE
LOW CURRENT
2
~
FI LE UNSAFE RESET
4
_ FILE UNSAFE 6
8
_ TWO SIDED 10
_ DISK CHANGE 12
SIDE SELECT
14
-
IN USE 16
HEAD LOAD 18
-
-
_ INDEX
20
SIGNAL
22
CONNECTOR
READY
VFO SYNC*
24
DRIVE SELECT 1
26
-
DRIVE SELECT
2 28
~
DRIVE SELECT 3
30
-
-
DRIVE SELECT 4
32
~
DIRECTION SELECT
34
~
STEP
36
WRITE DATA
38
-
WRITE GATE
40
-
_ TRACK
00 42
_ WR ITE PROTECT
44
READ DATA
46
- MFM4>
48
~
WINDOW*
50
*
SIGNALS USED ONLY WHEN VFO OPTION IS INSTALLED
Figure 3-2 Interface Lines
3.3 INPUT SIGNALS
This section describes the input signals that are carried
on the interface lines for the Model FDl165.
3.3.1 Drive Select 1 Through 4 (DSXl to 4)
These signals select one disk drive in the system for input/
output (I/O). When one of the signals (DSXl to DSX4) is
Low, the corresponding disk drive is selected. See Section
2.7 for the identification selection procedure.
3-3