User's Manual

MaxStream, Inc. 24XStream Wireless Module Manual v2.8

Command Mode

Command Mode allows several features, including the power-down and addressing options, to be

configured. These adjustable parameters offer greater flexibility to designers in configuring the

module to fit specific design criteria. There are three ways to enter Command Mode:

1) Assert RTS/CMD and send a binary command.

2) Send the sequence “+++” to send AT commands.

3) Assert (low) the *CONFIG pin and turn the power switch off and back on. (Do not tie

*CONFIG pin to microprocessor. See “Serial Port Operation” section for details.)

Once in Command Mode, the configurable parameters can be adjusted using either AT

commands or Binary commands, as explained below. Any parameters that are changed while in

Command Mode must be saved to non-volatile memory using the WR command, or else they will

reset to their stored value upon reset or power-up.

The following sections contain a description of the AT and Binary Command Modes along with

some examples. In these examples, sent or received ASCII characters are marked in quotations.

The quotation marks should not be included when sending commands to the 24XStream modules.

Carriage Returns (ASCII character 13) will be denoted as <CR>. Also, Binary values are

represented in this document with “<” and “>” characters and are not sent as part of the actual

command. All binary values are represented as hexadecimal values (HEX) in these examples,

denoted by an “H” after the number. The actual Binary Command values must all be sent in

binary with the least significant byte (LSB) sent first followed by the most significant byte (MSB)

if the value is larger than one byte.

AT Commands

AT commands can be sent to the module using ASCII commands and parameters. A special

break sequence is used so that the module will transition into AT Command Mode. The default

sequence for entering AT Command Mode is:

- No characters sent for 1 second. (Time modified by “BT” command)

- Send 3 plus characters “+++” within 1 second. (Character modified by “CC” command)

- No characters sent for 1 second. (Time modified by “AT” command)

The 24XStream module will respond by sending an “OK<CR>”.

All AT commands are sent as follows:

“AT” 2-Character

ASCII

Command

Optional

Space

Parameter

(HEX)

Carriage

Return

The ASCII command consists of “AT” followed by two alpha-numeric bytes, and the parameter

is a number represented as ASCII hexadecimal characters (0-9, A-F). The ASCII commands and

parameters are not case-sensitive. The optional space can be any non-alpha-numeric character.

After executing a recognized AT command, the module responds with an OK<CR>. If an

unrecognized command or a command with a bad parameter is received, the module will respond

with an ERROR<CR>. The modified value will be reset upon module power-down or reset

unless the “WR” command is issued to save the parameter to non-volatile memory.