4 floppy disk interface, Floppy disk interface, Floppy interface configuration – Kontron MSM800SEL User Manual
Page 46: Floppy interface connector, Floppy disk interface technology
MSM800SEV/SEL
/ Detailed System Description
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44
6.8.4 Floppy Disk Interface
The onboard floppy disk controller and ROM-BIOS support one or two floppy disk drives in any of the standard PC-DOS
and MS-DOS formats shown in the table.
Supported Floppy Formats:
Capacity
Drive Size
Tracks
Data Rate
DOS Version
1.2MB
5¼"
80
500KHz
3.0 - 6.22
720K
3½"
80
250KHz
3.2 - 6.22
1.44M
3½"
80
500KHz
3.3 - 6.22
Floppy Interface Configuration
The desired configuration of floppy drives (number and type) must be properly initialized in the board's CMOS -
configuration memory. This is generally done by using DEL or F2 at boot up time.
Floppy Interface Connector
The table shows the pin-out and signal definitions of the board's floppy disk interface connector. It is identical in pin-
out to the floppy connector of a standard AT. Note that, as in a standard PC or AT, both floppy drives are jumpered to
the same drive select: as the 'second' drive. The drives are uniquely selected as a result of a swapping of a group of
seven wires (conductors 10-16) that must be in the cable between the two drives. The seven-wire swap goes between
the computer board and drive 'A'; the wires to drive 'B' are unswapped (or swapped a second time). The 26pin high
density (1mm pitch FCC) connector has only one drive and motor select. The onboard jumper defines the drive A: or
B:. Default is always A:.
Floppy Disk Interface Technology
Only CMOS drives are supported. This means the termination resistors are 1K Ohm and 5¼" drives are not
recommended (TTL interface).
The 26pin connector:
FFC/FPC 0.3mm thick 1.0mm (0.039") pitch (MOLEX 52030 Series)
Floppy Disk Interface Connector:
FD26: Pin
Signal
Function
in/out
1
VCC
+5Volt
2
IDX
Index pulse
in
3
VCC
+5Volt
4
DS2
Drive select 2
out
5
VCC
+5Volt
6
DCHG
Disk change
in
10
M02
Motor on 2
out
12
DIRC
Direction select
out
14
STEP
Step
out
16
WD
Write data
out
17
GND
Signal ground
18
WE
Write enable
out
19
GND
Signal ground
20
TRKO
Track 0
in
21
GND
Signal grounds
22
WP
Write protect
in
23
GND
Signal ground
24
RDD
Read data
in
25
GND
Signal ground
26
HS
Head select
out