XE2400 Просмотр технического описания (PDF) - Xecom

Номер в каталоге

Компоненты Описание

Список матч

XE2400

Low-Cost, Embeddable, Serial 2400bps Modem

Xecom 

XE2400 AT Commands

The XE2400 uses "AT" commands for configuration and

control. This section describes use of the AT command

format and lists the AT commands, Registers and Result

codes. XE2400 "AT" commands have two operational

modes; Command Mode and Data Mode.

Command Buffer - No more than 40 characters,

including the AT prefix, may be loaded into the

command buffer. If the command buffer overflows, the

modem issues an "ERROR" result code and commands

are not executed.

Data Mode: The XE2400 enters data mode after it

connects with a remote modem and issues the

appropriate result code. In the Data Mode the modem

sends all data presented on Transmit Data (TXD) to the

remote modem and puts data from the remote modem

onto Received Data (RXD). When the modem exits

data mode, it issues a "NO CARRIER" result code.

Command Mode: The XE2400 enters command mode

on power-up, reset, a lost connection, or receipt of the

escape code. In command mode the modem accepts

commands from the host on transmit data. Appropriate

result codes are returned on received data.

Command Line Format

Command lines issued to the modem follow a strict

format. Each command begins with the prefix AT. The

command line is stored in the command buffer and

executed upon receipt of a carriage return. Until

executed, the command line can be edited with the

backspace key.

Command Prefix - Each command, except the A/

command, begins with the AT prefix. The "A" and "T"

may be either both upper case or both lower case but

cannot be of different cases. The prefix identifies the

speed and parity of the commands sent to the modem

by the host. Speed is determined by measuring the

width of the incoming bits. Parity is determined by

comparing the parity bit of the "A" and the "T."

Command Line - Commands may be strung together in

a single command line of up to 40 characters.

Commands are executed in the sequence they appear.

Spaces may be inserted into the command line but do

not fill space in the command buffer. A carriage return

terminates the command line and causes the commands

to be executed. Register S3 allows the user to select a

character other than a carriage return to terminate the

command line.

Command Line Editing - The backspace edits a

command line before it is executed. The backspace key,

(Control and H simultaneously on some systems),

erases the previous character in the command line.

Register S5 allows the user to select a character other

than a backspace to edit the command line.

Re-Execute Last Command - The A/ command causes

the modem to re-execute the last command line. This is

the only command which does not require the "AT"

prefix.

Omitted Parameters - Most commands include a

parameter which determines how the functions will be

set. When the command parameter is omitted from the

command string, it is assumed to be a 0.

Escape Characters - A 3 character escape sequence

maybe entered while in data mode to switch the modem

into command mode while on line. The escape

character, set by Register S2, must be entered 3 times

in succession within a 1 second guard time to execute

the escape. The default escape sequence is "+++."

Result Codes - The modem issues a result code after

each action. Result codes may be provided as full

words, numeric codes or may be disabled all together.

Each result code ends with a carriage return when

numeric result codes are chosen. When full word result

codes are chosen, a Line Feed and Carriage Return

preceed and follow each result code.

XECOM

(4)

XE2400

Share Link: