Setcadparams; Setlorasynchtimeout; Table 8-7: Setcadparams Command; Table 8-8: Cadexitmode Parameter - Semtech LR1121 User Manual

8.3.4 SetCadParams

Command SetCadParams(...) defines the LoRa CAD parameters.

Table 8-7: SetCadParams Command

Byte 0
Data from Host 0x02
Data to Host Stat1
•
SymbolNum defines the number of symbols used for the CAD detection.
•
DetPeak and DetMin define the sensitivity of the LoRa modem when trying to correlate to actual LoRa preamble
symbols. These two settings depend on the LoRa spreading factor, the Bandwidth, and the number of symbols used to
validate the detection. Choosing the right value must be carefully tested to ensure a good detection at sensitivity level,
and also to limit the number of false detections.
•
CadExitMode defines the action to be performed after a CAD operation.

Table 8-8: CadExitMode Parameter

Value CadExitMode
0x00 CAD_ONLY
0x01 CAD_RX
0x10 CAD_LBT
•
Timeout is only used when the CAD is performed with cadExitMode = CAD_RX or CAD_LBT.
If cadExitMode = CAD_RX, see

If cadExitMode = CAD_LBT, see


8.3.5 SetLoRaSynchTimeout

Command SetLoRaSynchTimeout(...) configures the LoRa modem to issue an RX timeout after exactly SymbolNum
symbols if no packet was detected by then.

Table 8-9: SetLoRaSynchTimeout Command

Byte
Data from Host
Data to Host
• SymbolNum: 0x00: No timeout (default value)
LR1121
User Manual Rev 1.1
UM.LR1121.W.APP Mar 2023
1 2 3
Symbol
0x0D DetPeak
Num
IrqStatus IrqStatus
Stat2
(31:24) (23:16)
The chip performs a CAD operation in LoRa. Once done and whatever the activity on the channel, the
device goes back to STBY_RC mode.
The device performs a CAD operation and if an activity is detected, it stays in RX until a packet is
detected or the timer reaches the timeout defined by
The device performs a CAD operation and if no activity is detected, it goes into TX mode with the
Timeout
defined as timeout parameter.
7.2.2 SetRx for Timeout definition
7.2.3 SetTx for Timeout definition
0
0x02
Stat1
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4 5
CadExit Timeout
DetMin
Mode (23:16)
IrqStatus IrqStatus
(15:8) (7:0)
Operation
Timeout
*31.25us
1
0x1B
Stat2
6 7
Timeout Timeout
(15:8) (7:0)
0x00 0x00 0x00
2
SymbolNum
IrqStatus (31:24)
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