Semtech LR1121 User manual

LR1121 Transceiver
User Manual
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LR1121
User Manual Rev 1.1
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Disclaimer
Long Range-Frequency Hopping Spread Spectrum (LR-FHSS) is a high link-budget, high-performance
technology combining the benefits of a modulation employing low energy per bit and advanced frequency
hopping schemes to achieve improved coexistence, spectral efficiency and sensitivity. Semtech Corp. holds
patents directed to aspects of the LR-FHSS technology.
Your use of LR-FHSS software made available by Semtech Corp. or its affiliates does not grant any rights to
their patents for LR-FHSS technology. Rights under Semtech patents may be available via various
mechanisms, including by purchasing Semtech SX1261, SX1262, SX1268, LR1110, LR1120 or LR1121
semiconductor devices, or their authorized counterparts from Semtech or its affiliates, or their respective
licensees.

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Table of Contents
1. Introduction.................................................................................................................................................... 12
1.1 Scope ................................................................................................................................................... 12
1.2 Overview ............................................................................................................................................. 12
2. System Processes.......................................................................................................................................... 13
2.1 System Modes ................................................................................................................................... 13
2.1.1 Boot.......................................................................................................................................... 14
2.1.2 Standby................................................................................................................................... 14
2.1.3 Calibrations............................................................................................................................ 15
2.1.4 Power Down.......................................................................................................................... 16
2.1.5 Sleep......................................................................................................................................... 17
2.1.6 Reset ........................................................................................................................................ 18
2.1.7 RX Mode.................................................................................................................................. 19
2.1.8 TX Mode.................................................................................................................................. 19
2.1.9 FS Mode .................................................................................................................................. 20
2.2 Startup Sequence ............................................................................................................................ 20
2.3 Firmware Upgrade .......................................................................................................................... 21
2.3.1 GetVersion ............................................................................................................................. 21
2.3.2 EraseFlash............................................................................................................................... 21
2.3.3 WriteFlashEncrypted.......................................................................................................... 22
2.4 Mode Transitions & Timings ........................................................................................................ 22
2.5 Info Page ............................................................................................................................................. 23
2.5.1 EraseInfoPage ....................................................................................................................... 23
2.5.2 WriteInfoPage....................................................................................................................... 23
2.5.3 ReadInfoPage........................................................................................................................ 24
3. Host-Controller Interface ........................................................................................................................... 25
3.1 Write Commands ............................................................................................................................. 25
3.2 Read Commands .............................................................................................................................. 25
3.3 Command Endianness ................................................................................................................... 26
3.4 Status Registers ................................................................................................................................ 27
3.4.1 GetStatus................................................................................................................................ 27
3.4.2 Stat1 ......................................................................................................................................... 27
3.4.3 Stat2 ........................................................................................................................................ 28
3.5 BUSY ..................................................................................................................................................... 29
3.6 Errors .................................................................................................................................................... 30
3.6.1 GetErrors................................................................................................................................. 30
3.6.2 ClearErrors.............................................................................................................................. 30
3.7 Memory Access ................................................................................................................................ 31
3.7.1 WriteRegMem32.................................................................................................................. 31
3.7.2 ReadRegMem32................................................................................................................... 31
3.7.3 WriteRegMemMask32 ....................................................................................................... 32
3.7.4 WriteBuffer8 .......................................................................................................................... 32
3.7.5 ReadBuffer8........................................................................................................................... 33
3.7.6 ClearRxBuffer ........................................................................................................................ 33
3.7.7 GetRandomNumber........................................................................................................... 33

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3.7.8 EnableSpiCrc ......................................................................................................................... 34
4. GPIOs................................................................................................................................................................. 35
4.1 Interrupts ............................................................................................................................................ 35
4.1.1 SetDioIrqParams.................................................................................................................. 37
4.1.2 ClearIrq.................................................................................................................................... 37
4.2 RF Switch Control ............................................................................................................................ 38
4.2.1 SetDioAsRfSwitch................................................................................................................ 38
4.2.2 DriveDiosInSleepMode ..................................................................................................... 39
4.3 Temperature Sensor ....................................................................................................................... 40
4.3.1 GetTemp................................................................................................................................. 40
5. Power Distribution....................................................................................................................................... 41
5.1 Power Modes .................................................................................................................................... 41
5.1.1 SetRegMode.......................................................................................................................... 41
5.2 VBAT Measurement ........................................................................................................................ 42
5.2.1 GetVbat ................................................................................................................................... 42
5.3 Power-On-Reset and Brown-Out-Reset ................................................................................... 43
5.4 Low Battery Detector ..................................................................................................................... 43
5.5 Over Current Protection ................................................................................................................ 43
6. Clock Sources ................................................................................................................................................. 44
6.1 RC Oscillators Clock References ................................................................................................. 44
6.2 High-Precision Clock References ............................................................................................... 44
6.2.1 32.768kHz Crystal ............................................................................................................... 44
6.2.2 32MHz Crystal....................................................................................................................... 44
6.2.3 32MHz TCXO ......................................................................................................................... 45
6.3 Commands ......................................................................................................................................... 46
6.3.1 ConfigLfClock........................................................................................................................ 46
6.3.2 SetTcxoMode........................................................................................................................ 47
7. Radio.................................................................................................................................................................. 48
7.1 Overview ............................................................................................................................................. 48
7.2 Commands ......................................................................................................................................... 49
7.2.1 SetRfFrequency.................................................................................................................... 49
7.2.2 SetRx ........................................................................................................................................ 49
7.2.3 SetTx......................................................................................................................................... 50
7.2.4 AutoTxRx ................................................................................................................................ 51
7.2.5 SetRxTxFallbackMode ....................................................................................................... 52
7.2.6 SetRxDutyCycle.................................................................................................................... 53
7.2.7 StopTimeoutOnPreamble ............................................................................................... 55
7.2.8 GetRssiInst.............................................................................................................................. 55
7.2.9 GetStats................................................................................................................................... 56
7.2.10 ResetStats ............................................................................................................................ 56
7.2.11 GetRxBufferStatus............................................................................................................. 57
7.2.12 SetRxBoosted ..................................................................................................................... 57
7.2.13 SetLoRaSyncWord ............................................................................................................ 58
7.2.14 GetLoRaRxHeaderInfos................................................................................................... 58
7.2.15 SetRssiCalibration............................................................................................................. 59
8. Modems ........................................................................................................................................................... 62

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8.1 Modem Configuration ................................................................................................................... 62
8.1.1 SetPacketType ..................................................................................................................... 63
8.1.2 GetPacketType ..................................................................................................................... 63
8.2 LoRa® Modem ................................................................................................................................... 64
8.2.1 LoRa Modulation Principle............................................................................................... 64
8.2.2 LoRa Packet Format............................................................................................................ 65
8.2.3 Channel Activity Detection (CAD)................................................................................. 66
8.3 LoRa® Commands ............................................................................................................................ 67
8.3.1 SetModulationParams....................................................................................................... 67
8.3.2 SetPacketParams ................................................................................................................. 68
8.3.3 SetCad ..................................................................................................................................... 68
8.3.4 SetCadParams....................................................................................................................... 69
8.3.5 SetLoRaSynchTimeout ...................................................................................................... 69
8.3.6 SetLoRaPublicNetwork...................................................................................................... 70
8.3.7 GetPacketStatus................................................................................................................... 70
8.4 (G)FSK Modem .................................................................................................................................. 71
8.4.1 (G)FSK Modulation Principle ........................................................................................... 71
8.4.2 (G)FSK Packet Engine ......................................................................................................... 71
8.4.3 (G)FSK Packet Format......................................................................................................... 72
8.4.4 SX128x Compatibility......................................................................................................... 73
8.5 (G)FSK Commands .......................................................................................................................... 74
8.5.1 SetModulationParams....................................................................................................... 74
8.5.2 SetPacketParams ................................................................................................................. 75
8.5.3 SetGfskSyncWord................................................................................................................ 76
8.5.4 SetPacketAdrs....................................................................................................................... 76
8.5.5 SetGfskCrcParams ............................................................................................................... 77
8.5.6 SetGfskWhitParams ............................................................................................................ 77
8.5.7 GetPacketStatus................................................................................................................... 78
8.6 LR-FHSS Modulation ....................................................................................................................... 79
8.6.1 LR-FHSS Modulation Principle........................................................................................ 79
8.7 LR-FHSS Commands ....................................................................................................................... 80
8.7.1 SetModulationParams....................................................................................................... 80
8.7.2 LrFhssBuildFrame................................................................................................................ 80
8.7.3 LrFhssSetSyncWord............................................................................................................ 82
8.7.4 Circuit Configuration for Long Range FHSS Transmission................................... 82
8.8 Data Buffer ......................................................................................................................................... 83
8.9 RSSI Functionality ............................................................................................................................ 83
9. Power Amplifiers........................................................................................................................................... 84
9.1 PA Supply Scheme .......................................................................................................................... 85
9.1.1 Low Power PA....................................................................................................................... 86
9.1.2 High Power PA...................................................................................................................... 87
9.2 PA Output Power ............................................................................................................................. 88
9.2.1 Low Power PA....................................................................................................................... 88
9.2.2 High Power PA...................................................................................................................... 89
9.2.3 High Frequency PA ............................................................................................................. 90
9.3 PA Current Consumption ............................................................................................................. 91

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9.3.1 Low Power PA....................................................................................................................... 91
9.3.2 High Power PA...................................................................................................................... 92
9.3.3 High Frequency PA ............................................................................................................. 94
9.4 Impedance Matching Networks ................................................................................................. 95
9.4.1 Multi-Band Operation........................................................................................................ 95
9.4.2 RF Switch Implementation............................................................................................... 97
9.4.3 Direct-Tie Implementation .............................................................................................. 98
9.5 Commands ......................................................................................................................................... 99
9.5.1 SetPaConfig........................................................................................................................... 99
9.5.2 SetTxParams........................................................................................................................100
10. Cryptographic Engine ............................................................................................................................101
10.1 Description ....................................................................................................................................101
10.2 Cryptographic Keys Definition ...............................................................................................101
10.3 Commands ....................................................................................................................................103
10.3.1 CEStatus..............................................................................................................................103
10.3.2 CryptoSetKey....................................................................................................................103
10.3.3 CryptoDeriveKey.............................................................................................................104
10.3.4 CryptoProcessJoinAccept............................................................................................105
10.3.5 CryptoComputeAesCmac............................................................................................106
10.3.6 CryptoVerifyAesCmac ...................................................................................................107
10.3.7 CryptoAesEncrypt01......................................................................................................108
10.3.8 CryptoAesEncrypt...........................................................................................................109
10.3.9 CryptoAesDecrypt ..........................................................................................................110
10.3.10 CryptoStoreToFlash.....................................................................................................111
10.3.11 CryptoRestoreFromFlash...........................................................................................111
10.3.12 CryptoSetParam............................................................................................................112
10.3.13 CryptoGetParam...........................................................................................................112
11. LR1121 Provisioning................................................................................................................................113
11.1 Description ....................................................................................................................................113
11.2 Provisioning Commands ..........................................................................................................113
11.2.1 GetChipEui.........................................................................................................................113
11.2.2 GetSemtechJoinEui........................................................................................................114
11.2.3 DeriveRootKeysAndGetPin .........................................................................................115
11.3 Crypto Engine Use With LoRaWAN V1.1.x ..........................................................................117
11.4 Crypto Engine Use with LoRaWAN V1.0.x ..........................................................................118
12. Test Commands........................................................................................................................................119
12.1 Regulatory Overview .................................................................................................................119
12.1.1 ETSI.......................................................................................................................................119
12.1.2 FCC .......................................................................................................................................119
12.2 Commands ....................................................................................................................................120
12.2.1 SetTxCw..............................................................................................................................120
12.2.2 SetTxInfinitePreamble...................................................................................................120
13. List Of Commands....................................................................................................................................121
13.1 Register / Memory Access Operations ................................................................................121
13.2 System Configuration / Status Operations ........................................................................122
13.3 Radio Configuration / Status Operations ...........................................................................123

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13.4 CryptoElement Configuration / Status Operations ........................................................125
13.5 Bootloader Commands .............................................................................................................126
14. Revision History ........................................................................................................................................127

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List of Figures
Figure 1-1: LR1121 Block Diagram ............................................................................................................. 12
Figure 2-1: LR1121 Modes and Transitions ............................................................................................. 13
Figure 2-2: Bootloader.................................................................................................................................... 14
Figure 3-1: Write Command Timing Diagram........................................................................................ 25
Figure 3-2: Read Command Timing Diagram ........................................................................................ 25
Figure 3-3: GetVersion Write Capture....................................................................................................... 26
Figure 3-4: GetVersion Read Capture........................................................................................................ 26
Figure 3-5: BUSY Timing Diagram.............................................................................................................. 29
Figure 5-1: LR1121 POR and BRN Functions........................................................................................... 43
Figure 6-1: LR1121 Thermal Insulation on PCB Top Layer................................................................. 45
Figure 6-2: TCXO Circuit Diagram .............................................................................................................. 45
Figure 7-1: Radio............................................................................................................................................... 48
Figure 7-2: LR1121 Current Profile During RX Duty Cycle Operation............................................ 54
Figure 7-3: RX Duty Cycle Upon Preamble Detection......................................................................... 54
Figure 8-1: LoRa /(G)FSK / LR-FHSS Command Order......................................................................... 62
Figure 8-2: LoRa Signal Bandwidth............................................................................................................ 64
Figure 8-3: LoRa Packet Format .................................................................................................................. 65
Figure 8-4: Fixed-Length Packet................................................................................................................. 72
Figure 8-5: Variable-Length Packet............................................................................................................ 72
Figure 8-6: LR-FHSS Spectral Plot Example............................................................................................. 79
Figure 9-1: LR1121 Power Amplifiers........................................................................................................ 84
Figure 9-2: PA Block Diagram ...................................................................................................................... 85
Figure 9-3: Low Power PA VR_PA Voltage vs. TxPower ............................................................. 86
Figure 9-4: High Power PA VR_PA Voltage vs. TxPower..................................................................... 87
Figure 9-5: Low Power PA Output Power vs. TxPower ....................................................................... 88
Figure 9-6: HP PA Output Power vs. TxPower........................................................................................ 89
Figure 9-7: High Frequency PA Output Power vs. TxPower.............................................................. 90
Figure 9-8: IDDTX vs TxPower, Low Power PA, DC-DC Configuration .......................................... 91
Figure 9-9: IDDTX vs TxPower, Low Power PA, LDO Configuration............................................... 92
Figure 9-10: IDDTX vs TxPower, High Power PA, DC-DC Configuration....................................... 93
Figure 9-11: IDDTX vs TxPower, High Power PA, LDO Configuration ........................................... 93
Figure 9-12: IDDTX vs TxPower, High Frequency PA, DC-DC Configuration.............................. 94
Figure 9-13: IDDTX vs TxPower, High Frequency PA, LDO Configuration................................... 94
Figure 9-14: RF Switch, Double PA Operation ....................................................................................... 97
Figure 9-15: RF Switch, Single PA Operation (High Power PA Example)...................................... 97
Figure 9-16: Single Tie implementation: Only one PA Used (High Power PA Example)......... 98
Figure 9-17: Single Tie implementation: Both PAs Used (High Power PA Example) ............... 98
Figure 11-1: Key Derivation Scheme For LoRaWAN 1.1.x ................................................................ 117
Figure 11-2: Key Derivation Scheme for LoRaWAN 1.0.x................................................................. 118

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List of Tables
Table 2-1: SetStandby Command............................................................................................................... 14
Table 2-2: CalibImage Command............................................................................................................... 15
Table 2-3: ISM Band Values........................................................................................................................... 15
Table 2-4: Calibrate Command.................................................................................................................... 16
Table 2-5: CalibParams Parameter ............................................................................................................. 16
Table 2-6: SetSleep Command .................................................................................................................... 17
Table 2-7: SleepConfig Parameter.............................................................................................................. 17
Table 2-8: Sleep Mode Summary................................................................................................................ 17
Table 2-9: Reboot Command....................................................................................................................... 18
Table 2-10: SetFsCommand.......................................................................................................................... 20
Table 2-11: GetVersion Command............................................................................................................. 21
Table 2-12: GetVersion Response............................................................................................................... 21
Table 2-13: EraseFlash Command.............................................................................................................. 21
Table 2-14: WriteFlashEncrypted Command ......................................................................................... 22
Table 2-15: Mode Transitions and Timings............................................................................................. 22
Table 2-16: EraseInfoPage Command....................................................................................................... 23
Table 2-17: WriteInfoPage Command ...................................................................................................... 23
Table 2-18: ReadInfoPage Command ....................................................................................................... 24
Table 2-19: ReadInfoPage Response......................................................................................................... 24
Table 3-1: GetStatus Command.................................................................................................................. 27
Table 3-2: Stat1 Values ................................................................................................................................... 27
Table 3-3: Stat2 Values ................................................................................................................................... 28
Table 3-4: GetErrors Command................................................................................................................... 30
Table 3-5: GetErrors Response..................................................................................................................... 30
Table 3-6: ClearErrors Command................................................................................................................ 30
Table 3-7: WriteRegMem32 Command.................................................................................................... 31
Table 3-8: ReadRegMem32 Command..................................................................................................... 31
Table 3-9: ReadRegMem32 Response ...................................................................................................... 31
Table 3-10: WriteRegMemMask32 Command ....................................................................................... 32
Table 3-11: WriteBuffer8 Command.......................................................................................................... 32
Table 3-12: ReadBuffer8 Command........................................................................................................... 33
Table 3-13: ReadBuffer8 Response ............................................................................................................ 33
Table 3-14: ClearRxBuffer Command........................................................................................................ 33
Table 3-15: GetRandomNumber Command .......................................................................................... 33
Table 3-16: GetRandomNumber Response ............................................................................................ 33
Table 3-17: EnableSpiCrc Command......................................................................................................... 34
Table 4-1: Digital I/Os...................................................................................................................................... 35
Table 4-2: IrqToEnable Interruption Mapping....................................................................................... 36
Table 4-3: SetDioIrqParams Command.................................................................................................... 37
Table 4-4: ClearIrq Command...................................................................................................................... 37
Table 4-5: SetDioAsRfSwitch Command.................................................................................................. 38
Table 4-6: DriveDiosInSleepMode Command ....................................................................................... 39
Table 4-7: GetTemp Command................................................................................................................... 40
Table 4-8: GetTemp Response..................................................................................................................... 40
Table 5-1: SetRegMode Command............................................................................................................ 41
Table 5-2: Power Regulation Options ....................................................................................................... 41
Table 5-3: GetVbat Command ..................................................................................................................... 42
Table 5-4: GetVbat Response....................................................................................................................... 42
Table 6-1: ConfigLfClock Command.......................................................................................................... 46

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Table 6-2: SetTcxoMode Command.......................................................................................................... 47
Table 6-3: TCXO Supply Voltage Programming Values...................................................................... 47
Table 7-1: SetRfFrequency Command...................................................................................................... 49
Table 7-2: SetRx Command .......................................................................................................................... 49
Table 7-3: SetTx Command........................................................................................................................... 50
Table 7-4: AutoTxRx Command .................................................................................................................. 51
Table 7-5: SetRxTxFallbackMode Command.......................................................................................... 52
Table 7-6: SetRxDutyCycle Command...................................................................................................... 53
Table 7-7: StopTimeoutOnPreamble Command.................................................................................. 55
Table 7-8: GetRssiInst Command................................................................................................................ 55
Table 7-9: GetRssiInst Response.................................................................................................................. 55
Table 7-10: GetStats Command .................................................................................................................. 56
Table 7-11: GetStats Response.................................................................................................................... 56
Table 7-12: ResetStats Command .............................................................................................................. 56
Table 7-13: GetRxBufferStatus Command............................................................................................... 57
Table 7-14: GetRxBufferStatus Response................................................................................................. 57
Table 7-15: SetRxBoosted Command ....................................................................................................... 57
Table 7-16: SetLoRaSyncWord Command .............................................................................................. 58
Table 7-17: GetLoRaRxHeaderInfos Command..................................................................................... 58
Table 7-18: GetLoRaRxHeaderInfos Response....................................................................................... 58
Table 7-19: SetRssiCalibration Command ............................................................................................... 59
Table 7-20: Gain Tune Values....................................................................................................................... 59
Table 7-21: Recommended Values for Reference EVK........................................................................ 59
Table 8-1: SetPacketType Command........................................................................................................ 63
Table 8-2: GetPacketType Command ....................................................................................................... 63
Table 8-3: GetPacketType Response ......................................................................................................... 63
Table 8-4: SetModulationParams Command......................................................................................... 67
Table 8-5: SetPacketParams Command ................................................................................................... 68
Table 8-6: SetCad Command ....................................................................................................................... 68
Table 8-7: SetCadParams Command......................................................................................................... 69
Table 8-8: CadExitMode Parameter ........................................................................................................... 69
Table 8-9: SetLoRaSynchTimeout Command ........................................................................................ 69
Table 8-10: SetLoRaPublicNetwork Command ..................................................................................... 70
Table 8-11: GetPacketStatus Command .................................................................................................. 70
Table 8-12: GetPacketStatus Response.................................................................................................... 70
Table 8-13: SetModulationParams Command....................................................................................... 74
Table 8-14: Bandwidth Parameter.............................................................................................................. 74
Table 8-15: SetPacketParams Command................................................................................................. 75
Table 8-16: SetGfskSyncWord Command................................................................................................ 76
Table 8-17: SetPacketAdrs Command ...................................................................................................... 76
Table 8-18: SetGfskCrcParams Command............................................................................................... 77
Table 8-19: SetGfskWhitParams Command............................................................................................ 77
Table 8-20: GetPacketStatus Command .................................................................................................. 78
Table 8-21: GetPacketStatus Response.................................................................................................... 78
Table 8-22: SetModulationParams Command....................................................................................... 80
Table 8-23: LrFhssBuildFrame Command ............................................................................................... 80
Table 8-24: Maximum user payload length, in bytes .......................................................................... 81
Table 8-25: LrFhssSetSyncWord Command............................................................................................ 82
Table 8-26: RSSI Information Origin and Meaning............................................................................... 83
Table 9-1: Optimized Settings for LP PA with the Same Matching Network.............................. 95
Table 9-2: Optimized Settings for HP PA with the Same Matching Network............................. 95
Table 9-3: Optimized Settings for HF PA with the Same Matching Network ............................. 95
Table 9-4: SetPaConfig Command............................................................................................................. 99
Table 9-5: DutyCycle Parameters................................................................................................................ 99

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Table 9-6: SetTxParams Command.......................................................................................................... 100
Table 9-7: RampTime Values...................................................................................................................... 100
Table 10-1: Cryptographic Keys Usage and Derivation.................................................................... 101
Table 10-2: CryptoSetKey Command...................................................................................................... 103
Table 10-3: CryptoSetKey Response........................................................................................................ 103
Table 10-4: CryptoDeriveKey Command............................................................................................... 104
Table 10-5: CryptoDeriveKey Response ................................................................................................. 104
Table 10-6: CryptoProcessJoinAccept Command.............................................................................. 105
Table 10-7: CryptoProcessJoinAccept Response................................................................................ 105
Table 10-8: CryptoComputeAesCmac Command.............................................................................. 106
Table 10-9: CryptoComputeAesCmac Response................................................................................ 106
Table 10-10: CryptoComputeAesCmac Command Example ......................................................... 106
Table 10-11: CryptoComputeAesCmac Response Example........................................................... 106
Table 10-12: CryptoVerifyAesCmac Command................................................................................... 107
Table 10-13: CryptoVerifyAesCmac Response..................................................................................... 107
Table 10-14: CryptoAesEncrypt01 Command ..................................................................................... 108
Table 10-15: CryptoAesEncrypt01 Response ....................................................................................... 108
Table 10-16: CryptoAesEncrypt Command .......................................................................................... 109
Table 10-17: CryptoAesEncrypt Response ............................................................................................ 109
Table 10-18: CryptoAesDecrypt Command.......................................................................................... 110
Table 10-19: CryptoAesDecrypt Response............................................................................................ 110
Table 10-20: CryptoStoreToFlash Command....................................................................................... 111
Table 10-21: CryptoAesDecrypt Response............................................................................................ 111
Table 10-22: CryptoRestoreFromFlash Command............................................................................. 111
Table 10-23: CryptoRestoreFromFlash Response............................................................................... 111
Table 10-24: CryptoSetParam Command.............................................................................................. 112
Table 10-25: CryptoSetParam Response................................................................................................ 112
Table 10-26: CryptoGetParam Command............................................................................................. 112
Table 10-27: CryptoGetParam Response............................................................................................... 112
Table 11-1: GetChipEui Command........................................................................................................... 113
Table 11-2: GetChipEui Response ............................................................................................................ 113
Table 11-3: GetSemtechJoinEui Command.......................................................................................... 114
Table 11-4: GetSemtechJoinEui Response............................................................................................ 114
Table 11-5: DeriveRootKeysAndGetPin Command (Standard) ..................................................... 115
Table 11-6: DeriveRootKeysAndGetPin Response ............................................................................. 115
Table 11-7: DeriveRootKeysAndGetPin Command (advanced).................................................... 116
Table 11-8: DeriveRootKeysAndGetPin Response (advanced)...................................................... 116
Table 11-9: LoRaWAN 1.0.x vs. 1.1.x Security Correspondence Table......................................... 118
Table 12-1: ETSI Test Signals ...................................................................................................................... 119
Table 12-2: SetTxCw Command................................................................................................................ 120
Table 12-3: SetTxInfinitePreamble Command..................................................................................... 120
Table 13-1: Register / Memory Access Operations............................................................................. 121
Table 13-2: System Configuration / Status Operations .................................................................... 122
Table 13-3: Radio Configuration / Status Operations ....................................................................... 123
Table 13-4: CryptoElement Configuration / Status Operations..................................................... 125
Table 13-5: Bootloader Commands......................................................................................................... 126
Table 14-1: Revision History ....................................................................................................................... 127

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1. Introduction
1.1 Scope
This document provides complete information on how to use the LR1121 transceiver in an application. It covers both
hardware and software aspects. For LR1121 functionalities and circuit specifications, refer to the LR1121 Datasheet.
Figure 1-1: LR1121 Block Diagram
1.2 Overview
The LR1121 chip is a long range, ultra-low power transceiver that provides ISM sub-GHz, a global 2.4 GHz band, and
1.9GHz-2.2GHz S-Band communication targeting terrestrial and satellite connectivity. For LPWAN use cases, the LR1121
supports LoRa® and (G)FSK and Long Range-Frequency Hopping Spread Spectrum (LR-FHSS) modulations. The device is
highly configurable over the 150 MHz-960MHz, 1.9-2.1GHz Satellite band and 2.4GHz ISM bands to meet different
application requirements utilizing the global LoRaWAN® Standard or proprietary protocols.
Besides the world-wide sub-GHz, 1.9-2.1GHz Satellite band and 2.4GHz transceiver capabilities, the LR1121 features a very
low power multi-band front-end.
LNA
LF0
PA
HP LF
PA
LP LF
RFO_HP_LF
RFO_LP_LF
RFI_P_LF0
RFI_N_LF0
PA
HF
LNA
HF
Balun
&
Match
RFIO_HF
ADCADC
PLL
VBAT_RF
VR_PA
VREG
DCC_SW
VBAT_DCC
VBAT_RF
DC-DC
LDO
BG/IREF
POR/
BRN
PDS
REGsREGs
HFXOSC
32MHz
CKS
LFXOSC
32kHz
HFRC
32MHz
LFRC
32kHz
XTA
XTB
DIO11/ 32k_P
DIO10/32k_N
VTCXO
DIO0/ BUSY
DIO1
DIO2
DIO3
DIO4
DIO9
DIO8
DIO7
DIO6
DIO5
150 - 960MHz, RX/TX 1.9 - 2.6GHz, RX/TX
REG_PA
Digital Baseband
+ DSP
CPU
RAMROM
NVM
IO Control
Digital Front-End
LoRa
modem
(G)FSK
modem
LoRa
modem
(G)FSK
modem
nRESET

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2. System Processes
2.1 System Modes
The LR1121 operating modes are shown in Figure 2-1: LR1121 Modes and Transitions:
Figure 2-1: LR1121 Modes and Transitions
S_POR
S_STARTUP
S_BOOT
S_CAL
S_STBY_RC
S_SLEEP
S_STBY_
XOSC
S_FSS_RX
S_TX
S
_R
X
S_WKtZͺ
KtE

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2.1.1 Boot
The bootloader is the first piece of software executed after power-on reset, and is located at the beginning of flash memory.
The detailed description in AN1200.57 LR1110 Program Memory Update applies to all LR11xx devices.
Two main tasks are assigned to the bootloader:
•The first task checks if a valid firmware is loaded before jumping there.
•The second task loads a firmware: it receives encrypted chunks of data sent through the SPI and performs an on-the-fly
decryption before writing data in flash.
Figure 2-2: Bootloader
2.1.2 Standby
This is the default mode of the LR1121. It is the return state from all other modes (except for specific fall-back options), and
the mode from which transitions to other modes are possible. All commands to configure the device should be issued in
this mode.
Two clocks are available: either the internal 32MHz RC oscillator (Standby RC mode), or an external 32MHz crystal/TCXO
(Standby Xosc mode). The RC clock is used by default for all automatic mode transitions. The crystal/TCXO clock allows
faster transitions to other modes at the expense of a higher power consumption.
2.1.2.1 SetStandby
Command SetStandby(...) sets the device in standby mode with the chosen 32MHz oscillator.
StdbyConfig selects the oscillator used in standby mode:
•0x00: Selects internal RC oscillator (Standby RC mode)
•0x01: Selects external Xtal/TCXO oscillator (Standby Xosc mode)
Table 2-1: SetStandby Command
Byte 0 1 2
Data from Host 0x01 0x1C StdbyConfig
Data to Host Stat1 Stat2 IrqStatus(31:24)
Bootloader
Firmware
Flash
The program starts here, then...
... jumps here!

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2.1.3 Calibrations
During the startup sequence, the device firmware calibrates the low and high frequency RC oscillators, the PLL, the ADC,
and the image rejection of the mixer at 915MHz. After the calibration procedure the device is set in Standby RC mode.
If operating at another frequency, the image calibration procedure must be restarted using command CalibImage(...).
An image calibration is advised after large temperature variations and optimal image rejection using command
CalibImage(...).
Image calibration is necessary if there is a frequency change > 10MHz, or a temperature change > 10°C.
2.1.3.1 CalibImage
The CalibImage(...) command launches an image calibration for the given range of frequencies Freq1 and Freq2 on the
RFI_N/P_LF sub-GHz path.
By default, the image calibration is made in the band 902 - 928MHz. Nevertheless, it is possible to request the device to
perform a new image calibration at other frequencies. The frequencies are given in 4MHz steps (Ex: 900MHz -> 0xE1).
The calibration is valid for all frequencies between the two parameters. Typically, the user selects the parameters Freq1 and
Freq2 from Table 2-3: ISM Band Values. The same frequency may be provided as Freq1 and Freq2 to perform a single
calibration for the Freq1 / Freq2 value.
The command operates in any mode. At the end of the calibration procedure, the device returns to Standby RC.
For other frequency bands, Freq1 and Freq2 values can be obtained using the following formula:
•Freq1 = floor( (fmin_mhz - 1)/4)
•Freq2 = ceil( (fmax_mhz + 1)/4)
In the case of POR, or when the device is recovering from power-down or sleep mode without retention, the image
calibration is performed as part of the initial calibration process and for optimal image rejection in the band 902 - 928MHz.
If a TCXO is fitted, the calibration fails.
Table 2-2: CalibImage Command
Byte 0 1 2 3
Data from Host 0x01 0x11 Freq1 Freq2
Data to Host Stat1 Stat2 IrqStatus (31:24) IrqStatus (23:16)
Table 2-3: ISM Band Values
Frequency Band [MHz] Freq1 Freq2
430-440 0x6B 0x6E
470-510 0x75 0x81
779-787 0xC1 0xC5
863-870 0xD7 0xDB
902-928 0xE1 (default) OxE9 (default)

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2.1.3.2 Calibrate
The Calibrate(...) command calibrates the requested blocks defined by the CalibParams parameter.
Command operates in any mode. At the end of the calibration procedure, the device returns to Standby RC.
2.1.4 Power Down
This is the lowest power consumption mode of the device. In this mode:
•All clocks are stopped, therefore no RTC is available
•There is no data retention, so device reconfiguration is necessary when leaving power down mode
•The BUSY signal is set to high, indicating to the host that the device is not ready to accept a command
•The device is put in power down mode with the SetSleep(...) command (refer to sleep mode description)
The device can exit this mode if NSS activity is detected.
Exiting this mode, the device performs a firmware restart, and sets the BUSY signal to low, indicating that the startup phase
has been performed successfully and that the device is ready to accept a command.
Table 2-4: Calibrate Command
Byte 0 1 2
Data from Host 0x01 0x0F CalibParams
Data to Host Stat1 Stat2 IrqStatus(31:24)
Table 2-5: CalibParams Parameter
Bits (7:6) 5 4 3 2 1 0
Name RFU PLL_TX IMG ADC PLL HF_RC LF_RC

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2.1.5 Sleep
Sleep mode configures the LR1121 into a low power consumption mode between radio operations, while retaining the
configuration register values and storing the firmware data in RAM. The BUSY signal is set to 1 with a pull-up and all MISO
SPI signals are high-Z when the LR1121 is in sleep mode. In sleep mode, all DIOs are in Hi-Z mode.
An optional 32kHz source can run either on the internal RC oscillator, or on the internal 32.768kHz oscillator driving an
external crystal. The 32.768kHz crystal oscillator allows a faster transition to standby mode, at the expense of higher power
consumption. In both cases, the RTC uses the 32kHz clock source to allow an automatic wake-up from Sleep mode.
2.1.5.1 SetSleep
SetSleep(...) puts the device in Powerdown or Sleep mode, and configures the timeout for automatic wake-up.
•SleepConfig defines in which sleep mode the device is put, and if it wakes up after a given time on the RTC event:
Retention (bit 0) defines if the device configuration and firmware data are retained:
1: 8kB of memory used for device state and firmware data retention
0: No data retention (Power Down mode)
Wakeup (bit 1) determines if the device wakes up after a given time on the RTC event:
1: Automatic wake-up enabled. Device automatically goes in Standby mode with RC oscillator, at end of
SleepTime timer. Configure the 32kHz clock source using command ConfigLfClock (...) for modem
applications.
0: Automatic wake-up disabled
Other bits are RFU and should be set to 0
•SleepTime: sleep time in number of 32.768kHz clock cycles, prior to automatic wake-up. Therefore, the sleep time can
vary from 0ms to 36.4 hours in steps of 30.52us
The device exits this mode upon the falling edge on the NSS signal even when automatic wakeup is enabled. Exiting this
mode, the device performs a firmware restart. When the BUSY signal is set to low, it indicates that the startup phase has
been performed successfully, and that the device is ready to accept a command.
The following table summarizes the sleep modes according to Retention and Wakeup bits configuration, with their current
consumption (RC /XTAL) and Standby transitions times (indicative values, for comparison only).
Table 2-6: SetSleep Command
Byte 0 1 2 3 4 5 6
Data from Host 0x01 0x1B SleepConfig SleepTime(31:24) SleepTime(23:16) SleepTime(15:8) SleepTime(7:0)
Data to Host Stat1 Stat2 IrqStatus (31:24) IrqStatus (23:16) IrqStatus (15:8) IrqStatus (7:0) 0x00
Table 2-7: SleepConfig Parameter
SleepConfig bit bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Definition RFU RFU RFU RFU RFU RFU Wakeup Retention
Table 2-8: Sleep Mode Summary
Retention Wakeup Datasheet Indicative Consumption (uA) Indicative Transition to Stby (ms)
0 0 Powerdown IDDPDN 30
0 1 Sleep IDDSL1 / IDDSL2 30
1 0 RFU - -
1 1 Sleep w/ 8 kB retention IDDSL3A / IDDSL4A <1

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2.1.6 Reset
Four reset sources are available to trigger a LR1121 restart and execute the startup sequence: Power-On-Reset / Brown-Out
Reset (POR/BRN), NRESET, and Reboot(...) command.
The BUSY signal is kept high during each one of the reset procedures, and returns to low when the restart procedure is
finished. At the end of the restart procedure, the device is ready to accept commands, it goes into Standby mode with RC
oscillator on (STBY_RC). All device context is lost during this operation, so the device must be re-configured and
recalibrated. POR/BRN and NRESET also trigger an authentication of the internal firmware.
2.1.6.1 Power-On-Reset and Brown-Out Reset
The LR1121 performs a restart if either of the following occurs:
•The battery voltage rises above the Power-On-Reset (POR) level
•The battery voltage temporarily drops below the Brown-Out Reset (BRN) level
Both POR and BRN trigger a full restart of the internal firmware. The Status field of the Stat2 status variable indicates if a POR
or BRN occurred.
Please refer to 5.3 Power-On-Reset and Brown-Out-Reset for addition information on the POR and BRN.
2.1.6.2 NRESET
Putting the NRESET signal to low for at least 100μs restarts the LR1121. The restart is equivalent to a Power-On Reset, and
the device follows the same restart sequence.
2.1.6.3 Reboot
Command Reboot(...) triggers a restart of the LR1121 firmware.
StayInBootLoader determines the type of reboot:
•0: Performs a software restart
•3: The boot-loader does not execute the firmware in flash, but allows firmware upgrades
•Other values are RFU
The 32kHz clock’s configuration is kept on a Reboot. Command ConfigLfClock(...) modifies the 32kHz clock
configuration.
Table 2-9: Reboot Command
Byte 0 1 2
Data from Host 0x01 0x18 StayInBootLoader
Data to Host Stat1 Stat2 IrqStatus (31:24)

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2.1.7 RX Mode
RX mode receives incoming RF packets on the RFI_N_LF0/RFI_P_LF0 pins in the sub-GHz band (150-960MHz) , and the
RFIO_HF pin in the 1.9-2.1GHz Satellite band and 2.4GHz band (2400-2500MHz), using one of the modems (LoRa or (G)FSK).
The device enters RX mode using command SetRx(...). At packet reception, an RX_DONE interrupt is generated, and
the received data is stored in the device data buffer. The RX operation can be automatically terminated after a packet
reception, duty-cycled or infinite, based on the application requirements.
While in RX mode, the LR1121 operates in different sub-modes:
•Continuous mode, the device remains in RX mode and looks for incoming packets until the host requests a different
mode.
•Single mode, the device automatically returns to a configured mode (Standby RC by default) after a packet reception.
•Single with timeout mode, the device automatically returns to a configured mode (Standby RC by default) after a
packet reception or after the given timeout. If a sync word (G)FSK or a LoRa header is detected, the timeout is stopped.
•RX Duty Cycle mode, the device goes periodically into RX mode to receive a packet before going back to Sleep mode,
until a packet is received.
•AutoTx mode (auto transmits a packet a given time after packet reception), the device goes into an intermediary mode
for the requested time after a packet reception, before entering TX mode to transmit the packet.
2.1.8 TX Mode
TX mode transmits RF packets using the selected sub-GHz PA on the RFO_LP_LF or RFO_HP_LF pins in the sub-GHz band
(150-960MHz) , and the RFIO_HF pin in the 1.9-2.1GHz Satellite band and 2.4GHz band (2400-2500MHz), using the modems
(LoRa, (G)FSK, or LR-FHSS).
After ramping-up the PA, the LR1121 transmits the data buffer at the given frequency, PA, output power and packet and
modulation configurations. When the last bit of the packet has been sent, a TX_DONE interrupt is generated, the PA
regulator is ramped down, the selected PA is switched OFF and the device goes back to Standby RC or Xosc mode,
depending on the FallBackMode configuration.
In TX mode, the BUSY signal goes low as soon as the PA has ramped-up and transmission of the preamble starts.
While in TX mode, the LR1121 operates in different sub-modes:
•Single mode, the device automatically returns to a configured mode (Standby RC by default) after a packet
transmission.
•Single mode with timeout, the device automatically returns to a configured mode (Standby RC by default) after a
packet transmission or after the given timeout.
•AutoRX mode, (automatically goes into RX mode a given time after transmitting a packet) the device goes into an
intermediary mode for the requested time after a packet transmission, before entering RX mode for reception of a
packet or until the configured timeout.
•Continuous Wave mode (CW mode), the device indefinitely transmits an unmodulated carrier at the predefined
frequency until another command is issued to change the mode.
•Infinite preamble mode: the device indefinitely transmits an infinite preamble of the configured modulation.

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2.1.9 FS Mode
Frequency Synthesis (FS) mode is an intermediate mode between standby mode and the RX or TX modes, where the PLL
and the associated regulators are switched on. The BUSY signal goes low as soon as the PLL is locked.
2.1.9.1 SetFs
Command SetFs(...) sets the device in Frequency Synthesis mode.
2.2 Startup Sequence
At power-up or after a reset, the device initiates its startup phase.
•The BUSY signal is set to high, indicating that the device is busy and cannot accept a command.
•When the power management unit and RC oscillator become available, the embedded CPU starts and executes the
internal firmware.
•At the end of the startup sequence, the device is set in Standby RC mode, the BUSY signal goes low and the device
accepts commands.
Table 2-10: SetFsCommand
Byte 0 1
Data from Host 0x01 0x1D
Data to Host Stat1 Stat2