This blog is to prepare the most common AT commands on nRF9160 and I will try to show how to use the at_client with link monitor for connecting the network.

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/at_version.html

Modem firmware versions

This document describes AT commands used in all versions of the nRF91 Series modem firmware.

The modem firmware versions that support a command are marked in the command description with the following version tag: vx.x.x

If a parameter is not supported by all versions of the modem firmware that support the command, the modem firmware versions that support the parameter are marked after the parameter with the version tag.

The version tags are read as follows:

  • If a command or parameter is markedv1.0.x, it is supported by modem firmware versions where the first two digits are 1 and 0.
  • If a command is markedv1.0.xv1.1.xv1.2.x, it is supported by modem firmware versions where the first two digits are 1 and 0, 1 and 1, or 1 and 2.
  • If a command or parameter is markedv1.1.x≥3, it is supported by modem firmware versions where the first two digits are 1 and 1 and the third digit is greater than or equal to 3.
  • If a command or parameter is markedv1.1.3, it is supported only by modem firmware version 1.1.3.

Click to access nrf91_at_commands_v1.3.pdf

The latest version of the Modem is

nRF9160 SiP modem firmware – what it is and how it works (Quick Update on the latest version of Modem firmware)

https://www.nordicsemi.com/Products/Low-power-cellular-IoT/nRF9160/

  • Pre-compiled binary, signed and encrypted
  • LTE Rel-13 Cat-M1 (LTE-M/eMTC)
  • LTE Rel-13 Cat-NB1 (NB-IoT)
  • Type B half duplex (HD), frequency division duplex (FDD)
  • Cat-M1 operation is enabled on E-UTRA Bands 1, 2, 3, 4, 5, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28 and 66.
  • Cat-NB1 operation is enabled on E-UTRA Bands 1, 2, 3, 4, 5, 8, 12, 13, 17, 19, 20, 25, 26, 28 and 66.
  • Power saving
    • Power Save Mode (PSM)
    • Idle-DRX and Connected Mode-DRX, DRX/extended-DRX in both
    • Independent clock and sleep state control
  • Interface to Application CPU
    • AT-command Interface for control
    • Socket Interface for Data
    • Modem production test support
    • Antenna Tuner per band Configurability with limited MIPI-RFFE support
  • Integrated TLS(1.2)/DTLS(1.2) and TCP/UDP/IPV4/IPV6 Dual Stack
    • Storage of TLS and Cloud credentials
  • SMS PDU Mode
  • Differential FOTA support enables small upgrade images
  • Support for SIM ATK and remote provisioning via Bearer Independent Protocol
    • eSIM support
  • GPS L1 C/A positioning
  • GPS L1 C/A receiver during LTE PSM and Idle DRX/extended-DRX modes
  • Single shot, fixed interval and continuous tracking modes

Upgrade the Modem firmware through nRF Connect Desktop (Programmer)

For example, it uses the programmer to download the latest LTE modem firmware (mfw_nrf9160_1.2.0.zip).

nRF91 AT Commands

This document describes the AT commands used to control the modem in nRF91 Series devices. The nRF91 series AT command API enables modem control for firmware running in the application core on nRF91 series devices.

The AT command API can also be exposed on one of the nRF91 serial interfaces by programming appropriate firmware in the application core. The nRF Connect SDK contains examples of such proxy firmware that can be run stand-alone or as part of other firmware functionality in the nRF91 application core. The stand-alone example is called at_client. This way, an external MCU or computer can get access to the modem API either exclusively or in addition to application firmware running on the nRF91 itself.

The AT commands described in this document apply to all versions of the nRF9160 module hardware. If a command applies only to a specific version of the module hardware, it is mentioned in the command description. The module hardware version is printed on the module label. For more information on nRF9160 module hardware versions, see nRF9160 Compatibility Matrix.

Program the at_client under the ncs\nrf\samples\nrf9160\at_client

I) General commands

DescriptionSyntaxAT Command e.g.
1Request model identification +CGMM+CGMMAT+CGMM
nRF9160-SICA
OK
2Request revision identification +CGMR+CGMRAT+CGMR
mfw_nrf9160_1.1.1
OK
3Request manufacturer identification +CGMI+CGMIAT+CGMI
Nordic Semiconductor ASA
OK
4Request product serial number identification +CGSN+CGSN[=]
0 – Respond with (default)
1 – Respond with +CGSN:
2 – Respond with +CGSN:
3 – Respond with +CGSN:		Reads the serial number
AT+CGSN
352656100367872
OK

Reads the IMEI:
AT+CGSN=1
+CGSN: “352656100367872”
OK
5Request IMSI +CIMI+CIMI [request]
<IMSI> [response]
IMSI, a string without double quotes
reads the IMSI string
AT+CIMI
284011234567890
OK
6Short software identification %SHORTSWVER
(Proprietary)		%SHORTSWVERAT%SHORTSWVER
%SHORTSWVER: nrf9160_1.1.2
OK
7Hardware identification %HWVERSION
(Proprietary)		%HWVERSIONrequests hardware identification
AT%HWVERSION
%HWVERSION: nRF9160 SICA B0A
OK
8Request modem build UUID %XMODEMUUID
(Proprietary)		%XMODEMUUIDrequests the UUID of a modem build
AT%XMODEMUUID
%XMODEMUUID: 25c95751-efa4-40d4-8b4a-1dcaab81fac9
OK
9Request ICCID %XICCID
(Proprietary)
%XICCIDrequests the ICCID of the USIM card
AT%XICCID
%XICCID: 8901234567012345678F
OK
10Set and read ODIS fields +ODIS+ODIS=,,,sets host device ID to HDID01, host device manufacturer to HDMAN01, host device model to HDMOD01, and host device software version to HDSW01
AT+ODIS=”HDID01″,”HDMAN01″,”HDMOD01″,”HDSW01″
OK

reads the current values
AT+ODIS?
+ODIS: “HDMAN01″,”HDMOD01″,”HDSW01”
OK
11Subscribe unsolicited ODIS notifications +ODISNTF+ODISNTF=<reporting>subscribes ODIS notificatons
AT+ODISNTF=1
OK
General Commands

II) Mobile termination control and status commands

DescriptionSyntaxAT Command (e.g.)
1Functional mode +CFUN+CFUN=<FUN>
0 – Sets the device to minimum functionality. Disables both transmit and receive RF
circuits and deactivates LTE and Global Navigation Satellite System (GNSS) services.
1 – Sets the device to full functionality.
4 – Sets the device to flight mode. Disables both transmit and receive RF circuits
and deactivates LTE and GNSS services.
20 – Deactivates LTE without shutting down GNSS services.
21 – Activates LTE without changing GNSS.
30 – Deactivates GNSS without shutting down LTE services.
31 – Activates GNSS without changing LTE.
40 – Deactivates UICC. v1.1.x≥3 v1.2.x
41 – Activates UICC. v1.1.x≥3 v1.2.x
44 – Sets the device to flight mode without shutting down UICC.


The read response parameter and its defined value is the following:
<fun>
0 – Power off and store. RF circuits are disabled by deactivating LTE and GNSS
services.
1 – Normal mode. The active mode is either LTE or GNSS, or both. Full functional
mode. Active modes depend on %XSYSTEMMODE setting.
4 – Flight mode. RF circuits are disabled by deactivating LTE and GNSS services.		activates the modem Normal mode
AT+CFUN=1
OK









reads the current functional mode
AT+CFUN?
+CFUN: 1
OK
2PIN code +CPINset command enters the PIN
+CPIN=<pin>[,<newpin>]

The read command checks if a PIN is needed or if a personalization lock is blocking the device start-up.
+CPIN:		enter PIN 1234
AT+CPIN=”1234″
OK

shows how to check if a PIN code is needed with the response that a PIN
code is required:
AT+CPIN?
+CPIN: “SIM PIN”
OK
3Remaining PIN retries +CPINR+CPINR command returns the number of remaining PIN retries for the UE passwords.
+CPINR=<sel_code>		checks the remaining entries for PIN:
AT+CPINR=”SIM PIN”
+CPINR: “SIM PIN”,3
OK
4List all available AT commands +CLACset command returns a list of all available AT commands.
+CLAC		lists the supported AT commands:
AT+CLAC
AT+CFUN
AT+COPS
…
OK
5Extended signal quality +CESQThe +CESQ command returns received signal quality parameters.
+CESQ
Response syntax:
+CESQ, <rxlev>,<ber>, rscp>, <econ>,<rsrq>,<rsrp>		reads the current signal quality, mapped Reference Signal Received
Quality (RSRQ) 31, and Reference Signal Received Power (RSRP) 62
AT+CESQ
+CESQ: 99,99,255,255,31,62
OK

returns supported values as compound values
AT+CESQ=?
+CESQ: (99),(99),(255),(255),(0-34,255),(0-97,255)
OK
6Signal quality notification %CESQ
(proprietary)		The set command subscribes or unsubscribes notifications of changes in signal quality
%CESQ=<n>
notification syntax (response)
%CESQ: <rsrp>,<rsrp_threshold_index>, <rsrq>, <rsrq_threshold_index>
<n>,
0 – Unsubscribe signal quality notifications
1 – Subscribe signal quality notifications

subscribes E-UTRA signal quality notifications:
AT%CESQ=1
OK

indicates a change in the measured average RSRP. The average RSRP is 62 and
mapped to threshold 3, the measured RSRQ average has been 12 and mapped to threshold index 1.
%CESQ: 62,3,12,1
7Restricted SIM access +CRSMset command transmits restricted commands to the SIM
+CRSM=<command>,[,fileid>[,<P1>,<P2>,<P3>[,<data>[,<pathid>]]]]		reads the forbidden Public Land Mobile Network (PLMN) list:
AT+CRSM=176,28539,0,0,12
+CRSM: 144,0,”64F01064F040FFFFFFFFFFFF”
OK
8Device activity status +CPASreturns the device activity status.
+CPAS		checks the activity status
AT+CPAS
+CPAS: 0
OK
9Indicator control +CIND+CIND command sets indicator states
+CIND=[<ind>[,<ind>[,…]]]		enables service and message indicators:
AT+CIND=1,0,1
OK

returns indicator states.
AT+CIND?
+CIND: 1,0,1
OK
IP address format +CGPIAF+CGPIAF command returns information about IPv6 address formatreads the current IPv6 address format:
AT+CGPIAF?
+CGPIAF: 1,1,1,0
OK
Current band %XCBAND
(Proprietary)		Nordic-proprietary %XCBAND command returns the current E-UTRA band
%XCBAND		reads the current band:
AT%XCBAND
%XCBAND: 13
OK
Read neighbor cells %NBRGRSRP
(Proprietary)		reads measured RSRP values of neighboring cells. The
command issues a valid response only when the modem is activated.
%NBRGRSRP
read command is not supported
Mode of operation (CS/PS) +CEMODEsets the CS/PS Mode of Operation. The mode is stored in the non-volatile memory when
the device is powered off with +CFUN=0. The command should only be used when the modem is not
activated.
+CEMODE=[<mode>]
<mode>
0 – PS mode 2 of operation
2 – CS/PS mode 2 of operation		sets the operating mode to PS mode 2:
AT+CEMODE=0
OK
Modem trace activation %XMODEMTRAC
(Proprietary)		%XBANDLOCK command sets locked bands. The band lock should be set before
activating modem with +CFUN.

%XBANKLOCK=<operation>[,<band_mask>]		sets permanent band 4 lock
AT%XBANDLOCK=1,”1000″
OK

sets runtime band 4 and 13 lock
AT%XBANDLOCK=2,”1000000001000″
OK
Data profile %XDATAPRFL
(Proprietary)		provide information on the application
use case to modem so that it can optimize power consumption.
%XDATAPRFL=<power_level>
0 – Ultra-low power
1 – Low power
2 – Normal
3 – Performance
4 – High performance
Set a low power level
AT%XDATAPRFL=1
OK
Connectivity statistics %XCONNSTAT
(Proprietary)		set command sets the connectivity statistics command.
%XCONNSTAT=<command>
0 – Stop
1 – Start		makes the LwM2M application start and stop connectivity statistics
AT%XCONNSTAT=1
OK
AT%XCONNSTAT=0
OK
Battery voltage %XVBAT
(Proprietary)		The Nordic-proprietary %XVBAT command reads battery voltage. v1.0.x v1.1.x v1.2.x
When the modem is active (either LTE communication or GPS receiver), the %XVBAT command returns
the latest voltage measured automatically during modem wakeup or reception. The voltage measured
during transmission is not reported. During modem inactivity, the modem measures battery voltage when
the %XVBAT command is received.
%XVBAT		reads the battery voltage in mV
AT%XVBAT
%XVBAT: 3600
OK

Integer. Battery voltage in mV, with a resolution of 4 mV.
Credential storage management %CMNGwrites, reads, deletes, and checks the existence of keys and certificates. The credentials are stored in the
non-volatile memory
%CMNG=<opcode>[,<sec_tag>[,<type>[,<content>[,<passwd>]]]]		writes the root certificate
AT%CMNG=0, 12345678, 0,”
—–BEGIN CERTIFICATE—–
MIIDSjCCA…
…bKbYK7p2CNTUQ
—–END CERTIFICATE—–”
OK

writes the client certificate
AT%CMNG=0,567890,1,”
—–BEGIN CERTIFICATE—–
MIIBc464…
…bW9aAa4
—–END CERTIFICATE—–”
OK
System mode %XSYSTEMMODE
(proprietary)		sets the modem system mode
%XSYSTEMMODE-=<M1_support>, <NB1_support>, <GNSS_support>, <LTE_perference>

+CME Error codes
518 – Not allowed in active state
522 – Band configuration not valid for selected mode
sets LTE Cat-M1 and GNSS as the system modes
AT%XSYSTEMMODE=1,0,1,0
OK

reads the supported system mode
AT%XSYSTEMMODE?
%XSYSTEMMODE: 1,0,0,0
OK

Network service related commands

DescriptionSyntaxAT Command e.g.
PLMN selection +COPSselects a PLMN automatically or manually, and reads and searches the current
mobile network.
+COPS=[<mode>[,<format>[,<oper>]]]
<mode>
0 – Automatic network selection
1 – Manual network selection
3 – Set of +COPS read command response.
<format>
0 – Long alphanumeric format. Only for 3.
1 – Short alphanumeric format. Only for 3 .
2 – Numeric format
<oper>
String. Mobile Country Code (MCC) and Mobile Network Code (MNC) values. Only
numeric string formats supported.		selects the automatic network selection
AT+COPS=0
OK

manually selects network 24407
AT+COPS=1,2,”24407″
OK

reads the current selection mode and network
AT+COPS?
+COPS: 0,2,”26201″,7
OK

reads the current selection mode and network with the operator name
in the alphanumeric format
AT+COPS?
+COPS: 0,0,”RADIOLINJA”,7
OK
Forced PLMN search %COPS
(Proprietary)		performs a forced PLMN search
%COPS		manual network search
AT%COPS=?
%COPS: (2,””,””,”26201″,7),(1,””,””,”26202″,7)
OK
Power saving mode setting +CPSMS+CPSMS command controls PSM settings

+CPSMS=[<mode>[,<Requested_Periodic-RAU>,<Requested_GPRS-READY-timer>
,<Requested_Periodic-TAU>[,<Requested_Active-Time>]]]

reads the current PSM settings
AT+CPSMS?
enables power saving mode and set timer values. Set Periodic-TAU timer
to 10 minutes and Active-Time to 1 minute.
AT+CPSMS=1,””,””,”10101010″,”00100001″
OK

disables power saving mode
AT+CPSMS=0
OK

disables power saving mode and sets timer to default values
AT+CPSMS=
OK

reads the current power saving mode settings
AT+CPSMS?
+CPSMS: 1,,,”10101111″,”01101100″
OK
eDRX setting +CEDRXS+CEDRXS command controls the setting of eDRX parameters

sets the requested eDRX parameters
+CEDRXS=[<mode>,[,<AcT-type>[,<Requested_eDRX_value>]]]

+CEDRXS: <AcT-type>,<Requested_eDRX_value>		Set:
enables eDRX and sets the requested eDRX value
AT+CEDRXS=1,4,”1000″
OK

unsolicited notification when 2 is used
+CEDRXP: 4,”1000″,”0101″,”1011″
OK

Read:
reads the requested eDRX value
AT+CEDRXS?
+CEDRXS: 4,”0001″
OK
Read EDRX dynamic parameters +CEDRXRDP+CEDRXRDP command reads dynamic eDRX parameters
+CEDRXRDP		reads eDRX parameters
AT+CEDRXRDP
+CEDRXRDP: 4,”0011″,”0010″,”1001″
OK
Read operator name +COPNreads operator names
+COPN		AT+COPN
OK
Network registration status +CEREG+CEREG command subscribes unsolicited network status notifications
Set
+CEREG=<n>
Read
Set:
subscribes notifications with level 2:
AT+CEREG=2
OK

Read:
reads the current registration status
AT+CEREG?
+CEREG: 2,1,”002F”,”0012BEEF”,7
OK
Operator ID %XOPERIDset command returns the operator ID.
%XOPERID
%XOPERID:<oper_id> [response]

0 – Operator not identified as any of those listed below.
1 – Verizon
2 – AT&T
3 – AT&T FirstNet
4 – AT&T Cricket
5 – AT&T Jasper
6 – China Telecom
7 – Softbank
8 – Telstra		returns the operator ID:
AT%XOPERID
%XOPERID: 1
OK
Read modem parameters %XMONITOR
(proprietary)		%XMONITOR command reads a set of modem parameters
Set command
%XMONITOR: <reg_status>,[<full_name>,<short_name>,<plmn>,<tac>,<AcT>,<band>,<cell_id>,
<phys_cell_id>,<EARFCN>,<rsrp>,<snr>,<NW-provided_eDRX_value>,<Active-Time>,<Periodic-TAU>]


 		reads modem parameters
AT%XMONITOR
%XMONITOR: 1,”EDAV”,”EDAV”,”26295″,”00B7″,7,4,”00011B07″,7,2300,63,39,””,
“11100000”,”11100000″,”00000000″
OK
Mobile network operator %XOPCONF
(proprietary)		onfigures modem for the selected mobile network
operator. v1.1

%XOPCONF=<op_conf>
1 – Automatically detected from IMSI
2 – Verizon
3 – AT&T
4 – China Telecom
5 – Softbank
6 – Telstra
7 – Bell
8 – LGU+		sets Verizon operator configuration
AT%XOPCONF=2
OK

reads the configured operator
AT%XOPCONF?
AT%XOPCONF: 2
OK
Network service related commands

Trouble-Shoot with LTE Link Monitor (Step by Step AT command)

LTE Link Monitor is a modem client application that monitors the modem/link status and activity using AT commands.

See the nRF91 AT Commands Reference Guide for the AT commands that are supported by the modem in nRF91 Series devices.

LTE Link Monitor is implemented as an app for the nRF Connect for Desktop application.

Open the LTE Link Monitor

Step 1:

Switch the modem to flight mode

AT+CFUN=4 
+CFUN=<FUN>
0 – Sets the device to minimum functionality. Disables both transmit and receive RF
circuits and deactivates LTE and Global Navigation Satellite System (GNSS) services.
1 – Sets the device to full functionality.
4 – Sets the device to flight mode. Disables both transmit and receive RF circuits
and deactivates LTE and GNSS services.
20 – Deactivates LTE without shutting down GNSS services.
21 – Activates LTE without changing GNSS.
30 – Deactivates GNSS without shutting down LTE services.
31 – Activates GNSS without changing LTE.
40 – Deactivates UICC. v1.1.x≥3 v1.2.x
41 – Activates UICC. v1.1.x≥3 v1.2.x
44 – Sets the device to flight mode without shutting down UICC.
Step 2:

sets the modem system mode

Only one supported LTE mode allowed at a time. This command is allowed only before
activating the modem using the CFUN=1 command. If the mode needs to be changed,the modem
must first be set to flight mode using the CFUN=4 command.

%XSYSTEMMODE=<M1_support>,<NB1_support>,<GNSS_support>,<LTE_preference>

+CME error codes
518 – Not allowed in active state
522 – Band configuration not valid for selected mode
The set command parameters and their defined values are the following:
<M1_support>
0 – LTE Cat-M1 not supported
1 – LTE Cat-M1 supported
<NB1_support>
0 – LTE Cat-NB1 not supported
1 – LTE Cat-NB1 supported
<GNSS_support>
0 – GNSS not supported
1 – GNSS supported
<LTE_preference>
<LTE preference> is for the coming releases. Not relevant in the current release.
0 – No preference
1 – LTE Cat-M1 preferred
2 – LTE Cat-NB1 preferred
The following command example sets LTE Cat-M1 and GNSS as the system modes. No preferred LTE mode set:

#sets LTE Cat-NB1 in system modes. No preferred LTE mode
 set
AT%XSYSTEMMODE=0,1,0,0
OK
Step 3:

Network registration status +CEREG (for debugging)

Syntax:
+CEREG=<n>

<n>
0 – Disable unsolicited result codes
1 – Enable unsolicited result codes +CEREG:<stat>
2 – Enable unsolicited result codes +CEREG:<stat>[,<tac>,<ci>,<AcT>]
3 – Enable unsolicited result codes
+CEREG:<stat>[,<tac>,<ci>,<AcT>[,<cause_type>,<reject_cause>]]
4 – Enable unsolicited result codes +CEREG: <stat>[,[<tac>],[<ci>],
[<AcT>][,,[,[<Active-Time>],[<Periodic-TAU>]]]]
5 – Enable unsolicited result codes +CEREG: <stat>[,[<tac>],[<ci>],
[<AcT>][,[<cause_type>],[<reject_cause>][,[<ActiveTime>],[<Periodic-TAU>]]]]

#subscribes notifications with level 2:
#2 – Enable unsolicited result codes 
AT+CEREG=2
OK

#subscribes notifications with level 5:
#5 – Enable unsolicited result codes
AT+CEREG=2
OK
Step 4:

Usage of ePCO/PCO in PDN connection establishment %XEPCO (depend on the operator)

ePCO (extended protocol configuration options)

https://itectec.com/spec/8-128-extended-protocol-configuration-options-epco/
https://www.sharetechnote.com/html/Handbook_LTE_ProtocolConfigurationOption.html

Syntax:
%XEPCO=<epco>
Step 5:

Enable the modem 

# 1 – Sets the device to full functionality.
AT+CFUN=1

You can also send the AT+CFUN? to get the modem status.

After done, it would successfully connect to HK CSL Limited operator NBIOT station.