Lora® Commands; Setmodulationparams; Table 8-4: Setmodulationparams Command - Semtech LR1121 User Manual

8.3 LoRa® Commands

8.3.1 SetModulationParams

Command SetModulationParams(...) configures the modulation parameters for the selected modem. Since the
parameters are modem dependent, the description hereafter is valid only for the LoRa modem.

Table 8-4: SetModulationParams Command

Byte 0
Data from Host 0x02
Data to Host Stat1
• SF defines the spreading factor (values other than those below are RFU). SF5 and SF6 are compatible with the SX126x
device family. SF6 can be made compatible with the SX127x family in implicit mode via a register setting
0x05: SF5

0x06: SF6

0x07:SF7

0x08: SF8

0x09: SF9

0x0A: SF10

0x0B: SF11

0x0C: SF12

•
BWL defines the LoRa modulation bandwidth (values other than those below are RFU):
0x03: LoRa_BW_62, LoRa Bandwidth 62.5kHz

0x04: LoRa_BW_125, LoRa Bandwidth 125kHz

0x05: LoRa_BW_250, LoRa Bandwidth 250kHz

0x06: LoRa_BW_500, LoRa Bandwidth 500kHz

0x0D: BW203 (2.4GHz band only)

0x0E: BW406 (2.4GHz band only)

0x0F: BW812 (2.4GHz band only)

•
CR configures the Coding Rate (values other than those below are RFU):
0x01: Short Interleaver CR= 4/5 Overhead Ratio 1.25

0x02: Short Interleaver CR= 4/6 Overhead Ratio 1.5

0x03: Short Interleaver CR= 4/7 Overhead Ratio 1.75

0x04: Short Interleaver CR= 4/8 Overhead Ratio 2

0x05: Long Interleaver CR= 4/5

0x06: Long Interleaver CR= 4/6

0x07: Long Interleaver CR= 4/8

•
LowDataRateOptimize reduces the number of bits per symbol:
0x00: LowDataRateOptimize off

0x01: LowDataRateOptimize on

1.Set bit 18 of register at address 0xf20414 to 1
2.Long Interleaver (CR=4/5, 4/6 and 4/8) is supported for packets of minimum Payload length of 8 bytes, and maximum Payload length of 253
bytes if the CRC is activated (255 bytes if the CRC is deactivated).
LR1121
User Manual Rev 1.1
UM.LR1121.W.APP Mar 2023
1 2
0x0F SF
Stat2 IrqStatus(31:24)
2
Overhead Ratio 1.25
2
Overhead Ratio 1.5
2
Overhead Ratio 2
www.semtech.com
3 4
BWL CR
IrqStatus(23:16) IrqStatus(15:8)
5
LowDataRateOptimize
IrqStatus (7:0)
1
.
67 of 130
Semtech
Proprietary & Confidential