Setpacketparams; Setcad; Table 8-5: Setpacketparams Command; Table 8-6: Setcad Command - Semtech LR1121 User Manual

8.3.2 SetPacketParams

Command SetPacketParams(...) configures the parameters of the RF packet for the selected modem. Since the
parameters are modem dependent, the description hereafter is valid only for the LoRa modem.

Table 8-5: SetPacketParams Command

Byte 0
Data from Host 0x02
Data to Host Stat1
•
PbLengthTX defines the length of the LoRa packet preamble.
Coded on 2 bytes, from 0x0001 (1) to 0xFFFF (65535). Minimum of 12 with SF5 and SF6, and of 8 for other SF

advised.
•
HeaderType defines if the header is explicit or implicit:
0x00: Explicit header (default)

0x01: Implicit header

•
PayloadLen defines the size of the payload (bytes) to transmit or the maximum size of the payload that the receiver can
accept.
In explicit header mode:

0: Reception of any payload length between 0 and 255 bytes allowed.

N: Reception of any payload length between 1 and N bytes accepted. Payload lengths of 0 or > N are rejected

and result in a HeaderErr IRQ.
In implicit header mode, PayloadLen configures the exact length of the payload to be transmitted or received.

•
CRC defines if the CRC is OFF or ON:
0x00: OFF

0x01: ON

•
InvertIQ defines if the I and Q signals are inverted.
0x00: Not inverted

0x01: Inverted

This command fails if no packet type has been set.

8.3.3 SetCad

Command SetCad(...) activates the CAD feature.

Table 8-6: SetCad Command

Byte
Data from Host
Data to Host
LR1121
User Manual Rev 1.1
UM.LR1121.W.APP Mar 2023
1 2
PbLengthTX PbLengthTX
0x10
(15:8)
IrqStatus IrqStatus
Stat2
(31:24)
0
0x02
Stat1
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3 4
HeaderType
(7:0)
IrqStatus
(23:16) (15:8)
1
0x18
Stat2
5 6
PayloadLen CRC
IrqStatus
0x00
(7:0)
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7
InvertIQ
0x00
68 of 130
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