Laird AC4490, User Manual

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AC4490 User Guide
Version 4.5
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AC4490 C
ONFIGURATION
AT Commands
The AT Command mode implemented in the AC4490 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.
Note: The Command/Data RX Disable feature can be enabled in firmware versions 8.6+. When enabled in
EEPROM, the radio disables the RF receiver while pin 17 (Command/Data) is Low. To ensure that
the radio is not in the middle of transmitting data to the OEM Host, the host should be prepared
to receive data for up to 20ms after taking pin 17 Low.
On-the-Fly Control
Commands
The AC4490 transceiver contains static memory that holds many of the parameters
that control the transceiver operation. Using the “CC” command set allows many of
these parameters to be changed during system operation. Because the memory
these commands affect is static, when the transceiver is reset, these parameters will
revert back to the settings stored in the EEPROM. While in CC Command mode
using pin 17 (Command/Data), the RF interface of the transceiver is still active.
Therefore, it can receive packets from remote transceivers while in CC Command
mode and forward these to the OEM Host.
AT Command Mode
While in CC Command mode using AT Commands, the RF interface of the
transceiver is active, but packets sent from other transceivers will not be received.
The transceiver uses Interface Timeout/RF Packet Size to determine when a CC
Command is complete. Therefore, there should be no delay between each character
as it is sent from the OEM Host to the transceiver or the transceiver will not
recognize the command.
The link between the OEM host and the transceiver does not need to resync when
exiting Command Mode. Acknowledgements will be sent while in Command Mode,
but the packet will be dumped on the receiving end. However, if an RF packet is
received before the Interface Timeout expires on a CC Command, the transceiver will
send the packet to the OEM Host before sending the CC Command response.
When an invalid command is sent, the radio scans the command to see if it has a
valid command followed by bytes not associated with the command, in which case
the radio discards the invalid bytes and accepts the command. In all other cases, the
radio returns the first byte of the invalid command to the user and discards the rest.
Table 1: Command Quick Reference
Command Name Command (All Bytes in Hex) Return (All Bytes in Hex)
Enter Command Mode 0x41 0x54 0x2B 0x2B 0x2B 0x0D 0xCC 0x43 0x4F 0x4D
Exit Command Mode 0xCC 0x41 0x54 0x4F 0x0D - 0xCC 0x44 0x41 0x54
Status Request 0xCC 0x00 0x00 - - - 0xCC Firmware
Version 0x00: Server
0x01: Client in range
0x03: Out of range
Change Channel 0xCC 0x02 New Channel - - 0xCC New Channel -
Change Server/Client 0xCC 0x03 0x00: Server
0x03: Client - - 0xCC Firm-ware
Version 0x00: Server
0x03: Client
Change Sync
Channel 0xCC 0x05 New Sync
Channel - - 0xCC New Sync
Channel - -