API frame format
XLR PRO Radio Frequency (RF) Modem User Guide
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The cmdID frame (API-identifier) indicates the API messages are contained in the cmdData frame (Identifier-specific
data). Multi-byte values are sent big endian. XLR PRO supports the following API frames:
API frame names and values sent from the XLR PRO:
API frame names and values received from the XLR PRO:
Note
Requests are less than 0x80, and responses are always 0x80 or higher.
Checksum
To test data integrity, a checksum is calculated and verified on non-escaped data.
To calculate
: Not including frame delimiters and length, add all bytes keeping only the lowest 8 bits of the result and
subtract the result from 0xFF.
To verify
: Add all bytes (include checksum, but not the delimiter and length). If the checksum is correct, the sum will
equal 0xFF.
XLR PRO API serial exchanges
AT commands
The following image shows the API frame exchange that takes place at the serial interface when sending an AT
command request to read or set an XLR PRO parameter. The response can be disabled by setting the frame ID to 0 in
the request.
API Frame Names
API ID
AT Command
0x08
AT Command - Queue Parameter Value
0x09
TX Request
0x10
Explicit TX Request
0x11
Remote Command Request
0x17
API Frame Names
API ID
AT Command Response
0x88
Modem Status
0x8A
Transmit Status
0x8B
RX Indicator (AO=0)
0x90
Explicit Rx Indicator (AO=1)
0x91
Remote Command Response
0x97