Specifications

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Pin 10 of each serial port connector is an enable signal which is normally left unconnected

When it is brought to a TTL high level, it disables the input signals. It is pulled low on the

board by a 1K ohm resistor. This signal is intended for board test purposes only.

J3 is the primary serial port, and is supported by the board's ROM-BIOS as the DOS "COM1"

device. The secondary serial port is J2; it is supported as the "COM2" device. However, it is

possible to disable either or both serial ports using the Ampro SETUP utility. (Note: if you

disable the primary port and enable the secondary port, then the secondary port gets installed as

COM1 by DOS, unless there is a primary port present somewhere else in the system.)

Table 2-13. Serial Port Connectors (J2,J3)

PIN SIGNAL

NAME

FUNCTION IN/OUT DB25

DB9

1 DCD 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

10 EN Input Enable in -- --

2.4.5 Floppy Disk Interface

The board's floppy controller option (U34) must be installed for this interface to be available. The

onboard floppy disk controller and ROM-BIOS support one or two floppy disk drives in any of

the standard DOS formats shown in Table 2-14.

Table 2-14. Supported Floppy Formats

CAPACITY DRIVE SIZE TRACKS DATA RATE DOS VERSION REQUIRED

360K 5-1/4” 40 250 KHz 2.1+

1.2M 5-1/4” 80 500 KHz 3.0+

720K 3-1/2” 80 250 KHz 3.2+

1.44M 3-1/2” 80 500 KHz 3.3+

Floppy Drive Considerations

As indicated in Table 2-14, nearly any type of soft-sectored, single or double-sided, 40 or 80

track, mini or micro floppy disk drive is usable. Naturally, the higher the quality of the drives

you use, the better your system's reliability. Here are some general considerations regarding the

selection, configuration, and connection of floppy drives to the Little Board/286.

n Drive Interface -- The drives used must be compatible with the board's floppy disk

connector signal interface, as described below. In general, any standard PC or AT

compatible 5-1/4" or 3- 1/2" floppy drive will work fine.