Floppy Disk Interface; Speaker Interface - DIGITAL-LOGIC MICROSPACE MSM800SEV Technical User's Manual

DIGITAL-LOGIC AG
4.4.4

Floppy Disk Interface

The onboard floppy disk controller and ROM-BIOS support one or two floppy disk drives in any of the stan-
dard PC-DOS and MS-DOS formats shown in the table .
Supported Floppy Formats
Capacity Drive size
1.2 MB 5-1/4"
720 K 3-1/2"
1.44 M 3-1/2"
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.
Floppy Interface connector
The table shows the pinout and signal definitions of the board's floppy disk interface connector. It is identical
in pinout 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 26 pin 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
We only support CMOS drives. That means that the termination resistors are 1 Kohm. 5 1/4"-drives are not
recommended (TTL interface).
The 26 pin Connector: FFC/FPC 0.3mm thick 1.0mm (0.039") pitch (MOLEX 52030 Serie)
Floppy Disk Interface Connector
FD26: Pin Signal Name
1 VCC
2 IDX
3 VCC
4 DS2
5 VCC
6 DCHG
10 M02
12 DIRC
14 STEP
16 WD
17 GND
18 WE
19 GND
20 TRKO
21 GND
22 WP
23 GND
24 RDD
25 GND
26 HS
4.4.5

Speaker Interface

One of the board's CPU device provides the logic for a PC compatible speaker port. The speaker logic signal
is buffered by a transistor amplifier, and provides approximately 0.1 watt of audio power to an external 8 ohm
speaker. Connect the speaker between VCC and speaker output to have no quiescient current.
Tracks Data rate
80 500 KHz
80 250 KHz
80 500 KHz
Function
+5 volts
Index Pulse
+5 volts
Drive Select 2
+5 volts
Disk Change
Motor On 2
Direction Select
Step
Write Data
Signal grounds
Write Enable
Signal grounds
Track 0
Signal grounds
Write Protect
Signal grounds
Read Data
Signal grounds
Head Select
25
MSM800 SEV Manual V1.0A
DOS version
3.0 - 6.22
3.2 - 6.22
3.3 - 6.22
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