Measurement-computing COM232/8AT Instrukcja Użytkownika Pobierz pdf (Strona 8)

8 COM232/8AT User’s Guide March 1998 1000-0901, rev 1.1

If you need to connect two DTEs together, you must make use of a customized cable known as a NULL MODEM or

MODEM Eliminator. A typical DTE-to-DTE cable is as follows:

This section provides a brief summary of the 16550 ACE internal registers. The registers are addressed

as indicated in the following table.

Note: The 16550 Asynchronous Communications Element (ACE) enters character mode on reset.

When the 16550 ACE is in character mode it appears as a 16450 ACE to the software.

16550 ACE Internal Register Map

DLAB

(see note)

A2 A1 A0 Description

0 000Receive Buffer (read only)

Transmitter Holding Register (write only)

0 001Interrupt Enable

x 010Interrupt Identification (read only)

FIFO Control (write only)

x 011Line Control

x 100MODEM Control

x 101Line Status

x 110MODEM Status

x 111Scratch

1 000Divisor Latch (LSB)

1 001Divisor Latch (MSB)

Note: DLAB is accessed through the Line Control Register.

Interrupt Enable Register

The bit definitions for the Interrupt Enable Register are as follows:

Interrupt Enable Register Definitions

D7 0

D6 0

D5 0

D4 0

D3 EDSSI MODEM Status

D2 ELSI Receiver Line Status

D1 ETBEI Transmitter Holding Register Empty

D0 ERBFI Received Data Available

1 2 3 4 5 6 7 8 9 10 11 12 13 ... 19 20

Brak uwag

Measurement-computing COM232/8AT Instrukcja Użytkownika Strona 8