Compaq MSEBX900 用户手册
DIGITAL-LOGIC AG
MSEBX800/900 Detailed Manual V1.0
34
5.2.4.
Floppy Disk Interface
Supported Floppy Formats
Capacity
Drive size
Tracks
Data rate
DOS version
1.2 MB
5-1/4"
80
500 KHz
3.0 - 6.22
720 K
3-1/2"
80
250 KHz
3.2 - 6.22
1.44 M
3-1/2"
80
500 KHz
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 bootup time.
CMOS – configuration memory. This is generally done by using DEL or F2 at bootup 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:.
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 1 KOhm and 5 1/4“-drives
are not recommended (TTL interface).
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 Name
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
MO2
Motor On 2
out
12
DIRC
Direction Select
out
14
STEP
Step
out
16
WD
Write Data
out
17
GND
Signal grounds
18
WE
Write Enable
out
19
GND
Signal grounds
20
TRKO
Track 0
in
21
GND
Signal grounds
22
WP
Write Protect
in
23
GND
Signal grounds
24
RDD
Read Data
in
25
GND
Signal grounds
26
HS
Head Select
out