Справочник Пользователя для AeroComm Corporation 4424200
3/23/2006
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4.4 LT4424 AT C
OMMANDS
The AT Command mode implemented in the LT4424 creates a virtual version of the Command/Data
pin. The “Enter AT Command Mode” Command asserts this virtual pin Low (to signify Command
Mode) and the “Exit AT Command Mode” Command asserts this virtual pin High (to signify Data).
Once this pin has been asserted Low, all On-the-Fly CC Commands documented in the manual are
supported.
pin. The “Enter AT Command Mode” Command asserts this virtual pin Low (to signify Command
Mode) and the “Exit AT Command Mode” Command asserts this virtual pin High (to signify Data).
Once this pin has been asserted Low, all On-the-Fly CC Commands documented in the manual are
supported.
When in AT Command Mode, the user cannot send or receive RF packets. However, an ambiguity of
approximately 10 ms exists where, if the “Enter AT Command Mode” command has been sent to the
transceiver at the same time an RF packet is being received, the RF packet could be sent to the OEM
Host before the “Enter AT Command Mode” command response is sent to the OEM Host.
approximately 10 ms exists where, if the “Enter AT Command Mode” command has been sent to the
transceiver at the same time an RF packet is being received, the RF packet could be sent to the OEM
Host before the “Enter AT Command Mode” command response is sent to the OEM Host.
NOTE: The RF packet size must be set to a minimum of 6 bytes in order to enter Command mode
using the Enter AT Command mode command.
using the Enter AT Command mode command.
4.4.1 Enter AT Command Mode
Prior to sending the “Enter AT Command Mode” command to the transceiver, the OEM Host must
ensure that the RF transmit buffer of the transceiver is empty (if the buffer is not empty, the ”Enter AT
Command Mode” command will be interpreted as packet data and will be transmitted out over the
RF). This can be accomplished by waiting up to one second between the last transmit packet and the
AT Command. The OEM Host must also ensure that the RF Packet Size for the transceiver is set to a
minimum of six. The Enter AT Command mode command is as follows:
ensure that the RF transmit buffer of the transceiver is empty (if the buffer is not empty, the ”Enter AT
Command Mode” command will be interpreted as packet data and will be transmitted out over the
RF). This can be accomplished by waiting up to one second between the last transmit packet and the
AT Command. The OEM Host must also ensure that the RF Packet Size for the transceiver is set to a
minimum of six. The Enter AT Command mode command is as follows:
OEM Host Command:
41h 54h 2Bh 2Bh 2Bh 0Dh
Transceiver Response:
CCh 43h 4Fh 4Dh
4.4.2 Exit AT Command Mode
To exit AT Command Mode, the OEM Host should send the following command to the transceiver:
OEM Host Command:
CCh 41h 54h 4Fh 0Dh
Transceiver Response:
CCh 44h 41h 54h