5 Configuration Dictionary - ExpressLink
5.1 Data values referenced 5.2 Data accessed through the CONF command5.3 Configuration commands

5 Configuration Dictionary

The configuration dictionary is a key-value store containing all the options necessary for the proper functioning of ExpressLink modules.

5.1 Data values referenced

5.1.1.1 Maximum key length is 16 characters

A key can be from 1 to 16 characters.

5.1.1.2 ERR9 INVALID KEY LENGTH

If the command sends a key with more than 16 characters, the ExpressLink module returns 'ERR9 INVALID KEY LENGTH'.

5.1.1.3 Valid key characters are 0-9, A-Z, a-z

A key may only contain alphanumeric characters in any order.

5.1.1.4 ERR10 INVALID KEY NAME

If a non-alphanumeric character is used in a key name, then the ExpressLink module returns 'ERR10 INVALID KEY NAME'.

5.1.1.5 ERR11 UNKNOWN KEY

All keys are predefined in the ExpressLink module. If an invalid key is used, then the module returns 'ERR11 UNKNOWN KEY'.

5.2 Data accessed through the CONF command

5.2.1 Assignment using 'CONF key=value'

Returns:
5.2.1.1 OK

If the write is successful, then the module returns 'OK'.

5.2.1.2 ERR9 INVALID KEY LENGTH

If the key is too long, then the module returns 'INVALID KEY LENGTH'.

5.2.1.3 ERR10 INVALID KEY NAME

If the key uses incorrect characters, then the module returns 'INVALID KEY NAME'.

5.2.1.4 ERR11 UNKNOWN KEY

If the key is not present in the system, then the module returns 'UNKNOWN KEY'.

5.2.1.5 ERR12 KEY READONLY

Some keys are read-only and cannot be written. If the key is not present in the system, then the module returns 'KEY READONLY'.

Example 1: 

AT+CONF VERSION=HELLO
ERR12 KEY READONLY

5.2.2 Retrieval using 'CONF? key'

Returns:
5.2.2.1 OK

If the read is successful, then the module returns 'OK'.

5.2.2.2 ERR9 INVALID KEY LENGTH

If the key is too long, then the module returns 'INVALID KEY LENGTH'.

5.2.2.3 ERR10 INVALID KEY NAME

If the key uses incorrect characters, then the module returns 'INVALID KEY NAME'.

5.2.2.4 ERR11 UNKNOWN KEY

If the key is not present in the system, then the module returns 'UNKNOWN KEY'.

5.2.2.5 ERR13 KEY WRITEONLY

Some keys are write-only and cannot be read. If the key cannot be read, then the module returns 'KEY WRITEONLY'.

Example 2:

AT+CONF? Passphrase
ERR13 KEY WRITEONLY

Key-value pairs can be used to set default values for command parameters, to set credentials, and to select connectivity options and timing preferences. These configuration key-value pairs are meant to be long-lived (persist) throughout the life of the application and are therefore stored in non-volatile memory. A basic set of key-value pairs is defined for all ExpressLink devices (EndPoint, Certificate). Some of these key-value pairs have factory presets and/or are read only.

Table 2 - Configuration Dictionary Persistent Keys

Configuration Parameter

Type

Persist

Initial Value

Factory Reset

Description

About

R

Y

Vendor - Model

N

A descriptive string that uniquely identifies the device make and model - communication capabilities.

Version

R

Y

Current module firmware version

N

The specific ExpressLink firmware version.

TechSpec

R

Y

Technical Specification Compatibility

N

The Technical Specification version this model is based upon (for example 'v0.6').

ThingName

R

Y

UID

N

The UID as natively provided by the module HW root of trust.

Certificate

R

Y

Device Birth Certificate

N

Device certificate used to authenticate with AWS cloud, signed by the manufacturer CA.

EndPoint

R/W

Y

Staging account endpoint

Y

The endpoint of the AWS account to which the ExpressLink module connects.

TopicRoot

R/W

Y

UID

Y

The default prefix that is used for all user defined topics.

Defender

R/W

Y

0

Y

The Device Defender upload interval in seconds. (0 indicates the service is disabled.)

HOTAcertificate

R/W

Y

{empty}

Y

Host OTA certificate (see chapter 9.10).

OTAcertificate

R/W

Y

Vendor OTA Certificate

N

Module OTA certificate. Vendor and Model specific (see chapter 9.5). (Wi-Fi modules only.)

SSID

R/W

Y

{Empty}

Y

SSID of local router (Wi-Fi modules only).

Passphrase

W

Y

{Empty}

Y

Passphrase of local router (Wi-Fi modules only).

APN

R/W

Y

{default}

Y

Cellular modules only.

Additional configuration parameters are non-persistent, and they are re-initialized at power up, or following any reset event. Among these are the topics list items. The host processor has to re-initialize them following any reset, and possibly a deep-sleep awakening (depending on the implementation).

Table 3 - Configuration Dictionary Non-persistent Keys

Configuration Parameter

Type

Persist

Initial Value

Description

IPv4Address

R

N

0.0.0.0

Current device IPv4 address

IPv6Address

R

N

::

Current device IPv6 address

DNSAddress

R

N

0.0.0.0

Current DNS address (IPv4 or IPv6)

GatewayAddress

R

N

0.0.0.0

Current router IP address (IPv4 or IPv6)

Topic1

R/W

N

{Empty}

Custom defined topic 1

Topic2

R/W

N

{Empty}

Custom defined topic 2

...

Topic<Max Topic>

R/W

N

{Empty}

Custom defined topic MaxTopic

5.3 Configuration commands

5.3.1 CONF key=value: Assign a value to selected configuration parameter

Assigns a specific value to the specified configuration parameter.

Returns:
OK

If the command was successful, the module returns 'OK'.

ERR# {message}

If the command was not successful, the module returns an error.

Example: 

AT+CONF SSID=MY_SSID    # Assign the preferred (local) Wi-Fi router SSID

5.3.2 CONF? key: Read value of selected configuration parameter

Query the value of a configuration parameter.

Returns:
OK {value}

If the command was successful, the module returns 'OK' followed by the value.

ERR# {message}

If the command was not successful, the module returns an error.

Example: 

AT+CONF? MyParameter