API frame format
XLR PRO Radio Frequency (RF) Modem User Guide
55
queued and not applied until either the “AT Command” (0x08) API type or the AC (Apply Changes) command is issued.
Register queries (reading parameter values) are returned immediately.
Send a command to change the baud rate (BD) to 115200 baud, but do not apply changes. (XLR PRO continues to
operate at the previous baud rate until changes are applied.)
Note
In this example, the parameter could have been sent as a zero-padded 2-byte or 4-byte value.
TX request
Frame type: 0x10
A TX Request API frame causes the XLR PRO to send data as an RF packet to the specified destination:
•
Broadcast transmission:
For broadcast transmission to all devices, set the 64-bit destination address to
0x000000000000FFFF.
•
Unicast transmission:
For unicast transmissions, set the 64 bit address field to the address of the desired
destination node.
Set the reserved field to 0xFFFE.
Frame fields
Offset
Example
Description
Start delimiter
0
0x7E
Length
MSB 1
0x00
Number of bytes between the length and the checksum
LSB 2
0x05
Frame-specific
data
Frame type
3
0x09
Frame ID
4
0x01
Identifies the UART data frame for the host to correlate
with a subsequent ACK (acknowledgment). If set to 0, no
response is sent.
AT command
5
0x42
Command Name—Two ASCII characters that identify the
AT command
BD
.
6
0x44
Parameter value
(ATBD7 = 115200
baud)
0x07
If present, indicates the requested parameter value to set
the given register. If no characters present, register is
queried.
Checksum
8
0x68
0xFF—The 8-bit sum of bytes from offset 3 to this byte.