DFU AT commands

The following commands list contains AT commands related to DFU requests.

The SLM application supports the following types of cloud-to-device Device Firmware Update (DFU) for the nRF52 Series of MCUs:

Note

You must configure SLM to use UART_2 for the DFU service.

Get request #XDFUGET

The #XDFUGET command sends various types of requests based on specific operation codes.

Set command

The set command allows you to send a DFU download request.

Syntax

AT#XDFUGET=<op>[,<host>,<image_1>[,<image_2>[,<sec_tag>]]]

  • The <op> parameter can accept one of the following values:

    • 0 - Cancel DFU (during download only).

    • 1 - Start downloading <image_1> and <image_2>.

    • 8 - Erase MCUboot secondary slot.

  • The <host> parameter is a string. It indicates the HTTP or HTTPS server name and optionally a port number.

  • The <image_1> parameter is a string. It indicates the first file image to download. If CONFIG_SLM_NRF52_DFU_LEGACY is defined, you must set <image_1> as the path to the init packet file (.dat). Otherwise, you must set <image_1> as the path to the MCUboot application update file (.bin).

  • The <image_2> parameter is a string. It indicates the second file image to download. If CONFIG_SLM_NRF52_DFU_LEGACY is defined, you must set <image_2> as the path to the file image (.bin). Otherwise, this parameter should not be set.

  • The <sec_tag> parameter is an integer. It indicates to the modem the credential of the security tag used for establishing a secure connection for downloading the image. It is associated with the certificate or PSK. Specifying the <sec_tag> is mandatory when using HTTPS.

Unsolicited notification

#XDFUGET: <dfu_step>,<info>

  • The <dfu_step> value is an integer. It indicates which image is being downloaded.

  • The <info> value is an integer. It can return the following values:

    • A value between 1 and 100 - The percentage of the download.

    • Any other value - Error code.

Examples

Get the image files for the legacy DFU from http://myserver.com/path/*.*:

AT#XDFUGET=1,"http://myserver.com","path/nrf52840_xxaa.dat","path/nrf52840_xxaa.bin"
OK
#XDFUGET: 1,14
...
#XDFUGET: 1,100

Erase the previous image after DFU:

AT#XDFUGET=8
OK

Get the image files for the nRF Connect SDK DFU from http://myserver.com/path/*.*:

AT#XDFUGET=1,"https://myserver.com","path/nrf52_app_update.bin","",1234
OK
#XDFUGET: 0,14
...
#XDFUGET: 0,100

Read command

The read command is not supported.

Test command

The test command tests the existence of the command and provides information about the type of its subparameters.

Syntax

#XDFUGET=?

Response syntax

#XDFUGET: <list of op value>,<host>,<image_1>,<image_2>,<sec_tag>

Examples

AT#XDFUGET=?
#XDFUGET: (0,1,8),<host>,<image_1>,<image_2>,<sec_tag>
OK

Get file size #XDFUSIZE

The #XDFUSIZE command returns the size of the downloaded (.bin) image file.

Set command

The set command allows you to get the size of the downloaded image file.

Syntax

AT#XDFUSIZE

Response syntax

XDFUSIZE: <file_size>,<download_size>

  • The <file_size> is an integer. It indicates the size of the DFU image file.

  • The <download_size> is an integer. It indicates the size that has been downloaded so far.

Examples

#XDFUGET: 1,100
OK

AT#XDFUSIZE
#XDFUSIZE: 17048,17048
OK

Read command

The read command is not supported.

Test command

The test command is not supported.

Run request #XDFURUN

The #XDFURUN command starts to run the DFU protocol over the UART connection.

Set command

The set command allows you to send a DFU run request.

Syntax

AT#XDFURUN=<start_delay>[,<mtu>,<pause>]

  • The <start_delay> parameter is an integer. It indicates the duration of the delay, in seconds, before the application starts to run the DFU protocol. This allows the nRF52 SoC to make the necessary preparations, like swapping to bootloader mode.

  • The <mtu> parameter is an integer. It indicates the size of the data chunk that is sent from the SLM to the nRF52. This parameter should be a multiple of 256 bytes and should not be greater than 4096 bytes. This parameter is ignored if CONFIG_SLM_NRF52_DFU_LEGACY is defined.

  • The <pause> parameter is an integer. It indicates the time, in milliseconds, that the SLM pauses after sending the data chunk of <mtu> size. This parameter must not be zero. This parameter is ignored if CONFIG_SLM_NRF52_DFU_LEGACY is defined.

Response syntax

#XDFURUN: <dfu_step>,<info>

  • The <dfu_step> is an integer. It indicates which step of the DFU protocol is being executed.

  • The <info> is an integer. It returns an error code when an error happens.

Examples

Run the legacy serial DFU protocol:

AT#XDFURUN=2
OK

Run the MCUboot-based DFU protocol:

AT#XDFURUN=1,1024,200
OK

Read command

The read command is not supported.

Test command

The test command tests the existence of the command and provides information about the type of its subparameters.

Syntax

#XDFURUN=?

Response syntax

#XDFURUN: <start_delay>,<mtu>,<pause>

Examples

AT#XDFURUN=?

#XDFURUN: <start_delay>,<mtu>,<pause>

OK