User's Manual

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

To query the current value of a particular command, send the corresponding AT command

without any parameters (carriage return is still sent). The response will be the current value of

that command reported as a hexadecimal number.

The following example demonstrates basic AT Command functionality in the 24XStream

module.

Example:

This example will change the user-defined Module Address to 1A0D (HEX) and check the

current value of the SM command. It will also write the new Module Address to non-volatile

memory.

Send Response

“+++” “OK<CR>”

“ATDT 1A0D<CR>” “OK<CR>”

“ATSM<CR>” “0”

“ATWR<CR>” (write to non-volatile memory) “OK<CR>”

“ATCN<CR>” (exit AT Command Mode)

Exiting AT Command Mode

There are two ways to exit the AT command mode and return to Idle Mode. If no valid AT

commands are received within the time specified by the AT Command Timeout parameter (CT

command), the module will return to Idle Mode automatically. Alternatively, the AT command

mode can be exited by sending the CN command.

Binary Commands

Binary command bytes are organized as follows:

– 1 byte – 2 bytes

When sending a Binary command to the 24XStream, the Command byte must be sent while the

RTS/CMD pin (Pin 5) is asserted. RTS/CMD can be de-asserted 100 microseconds after the stop

bit of the Command byte has been sent. It does not matter whether RTS/CMD is asserted when

the Parameter bytes are sent. The command will execute when all the parameters associated with

the command have been sent. If all parameters haven’t been received within 0.5 seconds the

module will return to Idle Mode. Note that when parameters are sent, they are always two bytes

long with the least significant byte sent first. When they are read, they are 1 or 2 bytes long as

indicated in the Command Table below.

Binary Command Mode allows multiple commands to be sent in sequence. When the RTS/CMD

pin is asserted, all incoming serial data will be interpreted as commands. Commands can be sent

in sequences of commands and their associated parameters. If RTS/CMD remains asserted, all

received commands will be executed by the 24XStream module. All modified parameters must

be stored in non-volatile memory by sending the WR command (08H with no parameters) before

powering down or resetting the module or the changes will be lost.