User manual

DIGITAL-LOGIC AG MSM800SEV/SEL/BEV/XEV/XEL Detailed Manual V1.5

4.4.2. Line Printer Port LPT1

A standard bi-directional LPT port is integrated into the MICROSPACE PC.

Further information about these signals is available in numerous publications, including the IBM technical

reference manuals for the PC and AT computers and from other reference documents.

The current is: IOH = 12mA IOL = 24mA

4.4.3. Serial Ports COM1-COM2

The serial channels are fully compatible with 16C550 UARTS. COM1 is the primary serial port and is

supported by the board's ROM-BIOS as the PC-DOS 'COM1' device. The secondary serial port is COM2; it

is supported as the 'COM2' device.

Standard: COM 1/2: National PC87317VUL: 2 x 16C550 compatible serial interfaces

Serial Port Connectors COM1, COM2:

Pin Signal Name Function in/out DB25 Pin

DB9 Pin

1 CD Data Carrier Detect in 8 1

2 DSR Data Set Ready in 6 6

3 RXD Receive Data in 3 2

4 RTS Request To Send out 4 7

5 TXD Transmit Data out 2 3

6 CTS Clear to Send in 5 8

7 DTR Data Terminal Ready out 20 4

8 RI Ring Indicator in 22 9

9 GND Signal Ground 7 5

The serial port signals are compatible with the RS232C specifications.

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

standard PC-DOS and MS-DOS formats shown in the table.

Supported Floppy Formats:

Capacity Drive size Tracks Data rate DOS version

1.2MB 5-1/4" 80 500KHz 3.0 - 6.22

720K 3-1/2" 80 250KHz 3.2 - 6.22

1.44M 3-1/2" 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:.