© Copyright LM Technologies Ltd Page 20 of 41
www.lm-technologies.com
User Manual for “LM068_BLE_Peri_0204” FW
6. AT command Parser on LM devices:
This section describes the AT command parser module on LM devices.
Serial terminals (such as Hercules, HyperTerminal, Tera Term or Putty) can be
used for serial communication with the LM devices.
Every AT command string shall be terminated with “CR-LF” character
sequence. The LM device will start to parse the AT command strings only after
receiving “CR-LF” sequence.
AT Commands are case insensitive e.g. “At*Resp=On”, “at*resp=on” and
“AT*RESP=ON” are all valid to make the Response setting ON.
AT command types:
1. Query only commands
2. Query and Set commands
3. Execution only command
The LM device reports messages to the user through the serial port for
indications like connection/pairing request, result of connection/pair procedure,
result of Bluetooth devices discovery, disconnection indication etc.
The LM device responds to each AT command as “OK”\r\n or “ERR”\r\n. After
this response, the LM device takes requested action or it will output report to
the user on UART.
If LM device does not receive “AT” as a start of new command, the LM device
may not respond to this command even if it is terminated with “\r\n” (e.g.
instead of “AT*NAME=?”, user issues “A*name=?”). In this case, LM device
will neglect the received string and will be ready to receive and process new
AT command.
When the LM device does not receive any command on UART for more than 30
seconds, the LM device enters in deep sleep mode. The LM device comes out
of this mode on any activity on UART lines or Bluetooth. If the user enters AT
commands while the adapter is in deep sleep mode, the LM device may lose
the first character of an AT command, e.g. for command “AT*NAME=?”,
adapter may show the echo as “t*name=?” or “Ñname=?” i.e. some garbage
character at start. The LM device will not respond to AT commands such as
ERR/OK, but it ignores this data and waits for a new AT command to process.
Some AT commands expects the BT address in the AT command string. In this
document “0126f357215” is considered a reference BT address, whereas 0012
is nap, 6f is uap and 357215 is lap in the BT address. Users should use the BT
address of their devices.
To Next Page