Semtech LR1121

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LR1121

User Manual Rev 1.1

UM.LR1121.W.APP Mar 2023

2 of 130

Semtech

Proprietary & Confidential

www.semtech.com

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.

Main Page

Table of Contents3
Introduction12
Scope12
Overview12
Figure 1-1: LR1121 Block Diagram12
System Processes13
System Modes13
Figure 2-1: LR1121 Modes and Transitions13
Boot14
Standby14
Figure 2-2: Bootloader14
Table 2-1: Setstandby Command14
Calibrations15
Table 2-2: Calibimage Command15
Table 2-3: ISM Band Values15
Power down16
Table 2-4: Calibrate Command16
Table 2-5: Calibparams Parameter16
Sleep17
Table 2-6: Setsleep Command17
Table 2-7: Sleepconfig Parameter17
Table 2-8: Sleep Mode Summary17
Reset18
Table 2-9: Reboot Command18
RX Mode19
TX Mode19
FS Mode20
Startup Sequence20
Table 2-10: Setfscommand20
Firmware Upgrade21
Getversion21
Eraseflash21
Table 2-11: Getversion Command21
Table 2-12: Getversion Response21
Table 2-13: Eraseflash Command21
Writeflashencrypted22
Mode Transitions & Timings22
Table 2-14: Writeflashencrypted Command22
Table 2-15: Mode Transitions and Timings22
Info Page23
Eraseinfopage23
Writeinfopage23
Table 2-16: Eraseinfopage Command23
Table 2-17: Writeinfopage Command23
Readinfopage24
Table 2-18: Readinfopage Command24
Table 2-19: Readinfopage Response24
Host-Controller Interface25
Write Commands25
Read Commands25
Figure 3-1: Write Command Timing Diagram25
Figure 3-2: Read Command Timing Diagram25
Command Endianness26
Figure 3-3: Getversion Write Capture26
Figure 3-4: Getversion Read Capture26
Status Registers27
Getstatus27
Stat127
Table 3-1: Getstatus Command27
Table 3-2: Stat1 Values27
Stat228
Table 3-3: Stat2 Values28
Busy29
Figure 3-5: BUSY Timing Diagram29
Errors30
Geterrors30
Clearerrors30
Table 3-4: Geterrors Command30
Table 3-5: Geterrors Response30
Table 3-6: Clearerrors Command30
Memory Access31
Writeregmem3231
Readregmem3231
Table 3-7: Writeregmem32 Command31
Table 3-8: Readregmem32 Command31
Table 3-9: Readregmem32 Response31
Writeregmemmask3232
Writebuffer832
Table 3-10: Writeregmemmask32 Command32
Table 3-11: Writebuffer8 Command32
Readbuffer833
Clearrxbuffer33
Getrandomnumber33
Table 3-12: Readbuffer8 Command33
Table 3-13: Readbuffer8 Response33
Table 3-14: Clearrxbuffer Command33
Table 3-15: Getrandomnumber Command33
Table 3-16: Getrandomnumber Response33
Enablespicrc34
Table 3-17: Enablespicrc Command34
Gpios35
Interrupts35
Table 4-1: Digital I/Os35
Table 4-2: Irqtoenable Interruption Mapping36
Setdioirqparams37
Clearirq37
Table 4-3: Setdioirqparams Command37
Table 4-4: Clearirq Command37
RF Switch Control38
Setdioasrfswitch38
Table 4-5: Setdioasrfswitch Command38
Drivediosinsleepmode39
Table 4-6: Drivediosinsleepmode Command39
Temperature Sensor40
Gettemp40
Table 4-7: Gettemp Command40
Table 4-8: Gettemp Response40
Power Distribution41
Power Modes41
Setregmode41
Table 5-1: Setregmode Command41
Table 5-2: Power Regulation Options41
VBAT Measurement42
Getvbat42
Table 5-3: Getvbat Command42
Table 5-4: Getvbat Response42
Power-On-Reset and Brown-Out-Reset43
Low Battery Detector43
Over Current Protection43
Figure 5-1: LR1121 por and BRN Functions43
Clock Sources44
RC Oscillators Clock References44
High-Precision Clock References44
Khz Crystal44
32Mhz Crystal44
32Mhz TCXO45
Figure 6-1: LR1121 Thermal Insulation on PCB Top Layer45
Figure 6-2: TCXO Circuit Diagram45
Commands46
Configlfclock46
Table 6-1: Configlfclock Command46
Settcxomode47
Table 6-2: Settcxomode Command47
Table 6-3: TCXO Supply Voltage Programming Values47
Radio48
Overview48
Figure 7-1: Radio48
Commands49
Setrffrequency49
Setrx49
Table 7-1: Setrffrequency Command49
Table 7-2: Setrx Command49
Settx50
Table 7-3: Settx Command50
Autotxrx51
Table 7-4: Autotxrx Command51
Setrxtxfallbackmode52
Table 7-5: Setrxtxfallbackmode Command52
Setrxdutycycle53
Table 7-6: Setrxdutycycle Command53
Figure 7-2: LR1121 Current Profile During RX Duty Cycle Operation54
Figure 7-3: RX Duty Cycle Upon Preamble Detection54
Stoptimeoutonpreamble55
Getrssiinst55
Table 7-7: Stoptimeoutonpreamble Command55
Table 7-8: Getrssiinst Command55
Table 7-9: Getrssiinst Response55
Getstats56
Resetstats56
Table 7-10: Getstats Command56
Table 7-11: Getstats Response56
Table 7-12: Resetstats Command56
Getrxbufferstatus57
Setrxboosted57
Table 7-13: Getrxbufferstatus Command57
Table 7-14: Getrxbufferstatus Response57
Table 7-15: Setrxboosted Command57
Setlorasyncword58
Getlorarxheaderinfos58
Table 7-16: Setlorasyncword Command58
Table 7-17: Getlorarxheaderinfos Command58
Table 7-18: Getlorarxheaderinfos Response58
Setrssicalibration59
Table 7-19: Setrssicalibration Command59
Table 7-20: Gain Tune Values59
Table 7-21: Recommended Values for Reference EVK59
Modems62
Modem Configuration62
Figure 8-1: Lora /(G)FSK / LR-FHSS Command Order62
Setpackettype63
Getpackettype63
Table 8-1: Setpackettype Command63
Table 8-2: Getpackettype Command63
Table 8-3: Getpackettype Response63
Lora® Modem64
Lora Modulation Principle64
Figure 8-2: Lora Signal Bandwidth64
Lora Packet Format65
Figure 8-3: Lora Packet Format65
Channel Activity Detection (CAD)66
Lora® Commands67
Setmodulationparams67
Table 8-4: Setmodulationparams Command67
Setpacketparams68
Setcad68
Table 8-5: Setpacketparams Command68
Table 8-6: Setcad Command68
Setcadparams69
Setlorasynchtimeout69
Table 8-7: Setcadparams Command69
Table 8-8: Cadexitmode Parameter69
Table 8-9: Setlorasynchtimeout Command69
Setlorapublicnetwork70
Getpacketstatus70
Table 8-10: Setlorapublicnetwork Command70
Table 8-11: Getpacketstatus Command70
Table 8-12: Getpacketstatus Response70
G)FSK Modem71
G)FSK Modulation Principle71
G)FSK Packet Engine71
G)FSK Packet Format72
Figure 8-4: Fixed-Length Packet72
Figure 8-5: Variable-Length Packet72
Sx128X Compatibility73
G)FSK Commands74
Setmodulationparams74
Table 8-13: Setmodulationparams Command74
Table 8-14: Bandwidth Parameter74
Setpacketparams75
Table 8-15: Setpacketparams Command75
Setgfsksyncword76
Setpacketadrs76
Table 8-16: Setgfsksyncword Command76
Table 8-17: Setpacketadrs Command76
Setgfskcrcparams77
Setgfskwhitparams77
Table 8-18: Setgfskcrcparams Command77
Table 8-19: Setgfskwhitparams Command77
Getpacketstatus78
Table 8-20: Getpacketstatus Command78
Table 8-21: Getpacketstatus Response78
LR-FHSS Modulation79
LR-FHSS Modulation Principle79
Figure 8-6: LR-FHSS Spectral Plot Example79
LR-FHSS Commands80
Setmodulationparams80
Lrfhssbuildframe80
Table 8-22: Setmodulationparams Command80
Table 8-23: Lrfhssbuildframe Command80
Table 8-24: Maximum User Payload Length, in Bytes81
Lrfhsssetsyncword82
Circuit Configuration for Long Range FHSS Transmission82
Table 8-25: Lrfhsssetsyncword Command82
Data Buffer83
RSSI Functionality83
Table 8-26: RSSI Information Origin and Meaning83
Power Amplifiers84
Figure 9-1: LR1121 Power Amplifiers84
PA Supply Scheme85
Figure 9-2: PA Block Diagram85
Low Power PA86
Figure 9-3: Low Power PA VR_PA Voltage Vs86
High Power PA87
Figure 9-4: High Power PA VR_PA Voltage Vs. Txpower87
PA Output Power88
Low Power PA88
Figure 9-5: Low Power PA Output Power Vs. Txpower88
High Power PA89
Figure 9-6: HP PA Output Power Vs. Txpower89
High Frequency PA90
Figure 9-7: High Frequency PA Output Power Vs. Txpower90
PA Current Consumption91
Low Power PA91
Figure 9-8: IDDTX Vs Txpower, Low Power PA, DC-DC Configuration91
High Power PA92
Figure 9-9: IDDTX Vs Txpower, Low Power PA, LDO Configuration92
Figure 9-10: IDDTX Vs Txpower, High Power PA, DC-DC Configuration93
Figure 9-11: IDDTX Vs Txpower, High Power PA, LDO Configuration93
High Frequency PA94
Figure 9-12: IDDTX Vs Txpower, High Frequency PA, DC-DC Configuration94
Figure 9-13: IDDTX Vs Txpower, High Frequency PA, LDO Configuration94
Impedance Matching Networks95
Multi-Band Operation95
Table 9-1: Optimized Settings for LP PA with the same Matching Network95
Table 9-2: Optimized Settings for HP PA with the same Matching Network95
Table 9-3: Optimized Settings for HF PA with the same Matching Network95
RF Switch Implementation97
Figure 9-14: RF Switch, Double PA Operation97
Figure 9-15: RF Switch, Single PA Operation (High Power PA Example)97
Direct-Tie Implementation98
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
Commands99
Setpaconfig99
Table 9-4: Setpaconfig Command99
Table 9-5: Dutycycle Parameters99
Settxparams100
Table 9-6: Settxparams Command100
Table 9-7: Ramptime Values100
Cryptographic Engine101
Description101
Cryptographic Keys Definition101
Table 10-1: Cryptographic Keys Usage and Derivation101
Commands103
Cestatus103
Cryptosetkey103
Table 10-2: Cryptosetkey Command103
Table 10-3: Cryptosetkey Response103
Cryptoderivekey104
Table 10-4: Cryptoderivekey Command104
Table 10-5: Cryptoderivekey Response104
Cryptoprocessjoinaccept105
Table 10-6: Cryptoprocessjoinaccept Command105
Table 10-7: Cryptoprocessjoinaccept Response105
Cryptocomputeaescmac106
Table 10-8: Cryptocomputeaescmac Command106
Table 10-9: Cryptocomputeaescmac Response106
Table 10-10: Cryptocomputeaescmac Command Example106
Table 10-11: Cryptocomputeaescmac Response Example106
Cryptoverifyaescmac107
Table 10-12: Cryptoverifyaescmac Command107
Table 10-13: Cryptoverifyaescmac Response107
Cryptoaesencrypt01108
Table 10-14: Cryptoaesencrypt01 Command108
Table 10-15: Cryptoaesencrypt01 Response108
Cryptoaesencrypt109
Table 10-16: Cryptoaesencrypt Command109
Table 10-17: Cryptoaesencrypt Response109
Cryptoaesdecrypt110
Table 10-18: Cryptoaesdecrypt Command110
Table 10-19: Cryptoaesdecrypt Response110
Cryptostoretoflash111
Cryptorestorefromflash111
Table 10-20: Cryptostoretoflash Command111
Table 10-21: Cryptoaesdecrypt Response111
Table 10-22: Cryptorestorefromflash Command111
Table 10-23: Cryptorestorefromflash Response111
Cryptosetparam112
Cryptogetparam112
Table 10-24: Cryptosetparam Command112
Table 10-25: Cryptosetparam Response112
Table 10-26: Cryptogetparam Command112
Table 10-27: Cryptogetparam Response112
LR1121 Provisioning113
Description113
Provisioning Commands113
Getchipeui113
Table 11-1: Getchipeui Command113
Table 11-2: Getchipeui Response113
Getsemtechjoineui114
Table 11-3: Getsemtechjoineui Command114
Table 11-4: Getsemtechjoineui Response114
Deriverootkeysandgetpin115
Table 11-5: Deriverootkeysandgetpin Command (Standard)115
Table 11-6: Deriverootkeysandgetpin Response115
Table 11-7: Deriverootkeysandgetpin Command (Advanced)116
Table 11-8: Deriverootkeysandgetpin Response (Advanced)116
Crypto Engine Use with Lorawan V1.1.X117
Figure 11-1: Key Derivation Scheme for Lorawan 1.1.X117
Crypto Engine Use with Lorawan V1.0.X118
Figure 11-2: Key Derivation Scheme for Lorawan 1.0.X118
Table 11-9: Lorawan 1.0.X Vs. 1.1.X Security Correspondence Table118
Test Commands119
Regulatory Overview119
Etsi119
Fcc119
Table 12-1: ETSI Test Signals119
Commands120
Settxcw120
Settxinfinitepreamble120
Table 12-2: Settxcw Command120
Table 12-3: Settxinfinitepreamble Command120
List of Commands121
Register / Memory Access Operations121
Table 13-1: Register / Memory Access Operations121
System Configuration / Status Operations122
Table 13-2: System Configuration / Status Operations122
Radio Configuration / Status Operations123
Table 13-3: Radio Configuration / Status Operations123
Table 13-4: Cryptoelement Configuration / Status Operations125
Table 13-5: Bootloader Commands126
Table 14-1: Revision History127

Semtech LR1121 - Page 2

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