Hello Vimal, to verify that you have a copy of Probe installed in your PC, you can browse to the following path:

C:\SiliconLabs\SimplicityStudio\v4\developer\tools\ucprobe

You can also install the tool by launching Simplicity Studio's Package Manager:

1. Click Help -> Update Software

2. Select the tab Tools

3. Scroll Down the list of tools until your find Micrium uC/Probe

4. Press the button Install

And, if none of these work, then you can always install the tool independent of Simplicity Studio and directly from the Micrium website at:

https://www.micrium.com/download/ucprobe-win-installer/

In this case, you will not be able to launch the tool from Simplicity Studio but, you can still launch it like any other Windows Application.

Hello Vimal, to verify that you have a copy of Probe installed in your PC, you can browse to the following path:

C:\SiliconLabs\SimplicityStudio\v4\developer\tools\ucprobe

You can also install the tool by launching Simplicity Studio's Package Manager:

1. Click Help -> Update Software

2. Select the tab Tools

3. Scroll Down the list of tools until your find Micrium uC/Probe

4. Press the button Install

And, if none of these work, then you can always install the tool independent of Simplicity Studio and directly from the Micrium website at:

https://www.micrium.com/download/ucprobe-win-installer/

In this case, you will not be able to launch the tool from Simplicity Studio but, you can still launch it like any other Windows Application.

Hello Michel, we don't have any official examples that we can support yet but, I can share some code that may help you (see attached file MicriumOS_IO_SPI.zip) along with this link: https://doc.micrium.com/display/OSUM50600/Integrating+SPI+Into+Your+Project

The other option is going with a single file, self-contained low-level SPI driver (see attached file low_level_spi.c).

Both solutions are through DMA.

Introduction

When it comes to IoT device management, over-the-air (OTA) firmware updates play a key role.

OTA enables product manufacturers to remotely update connected devices with bug fixes, feature enhancements and security patches.

If you are evaluating one of our EFM32 32-bit MCUs such as the one onboard the Giant Gecko GG11 Starter Kit (SLSTK3701A) and want to learn a simple way to enable OTA firmware updates then this blog will get you started by presenting the example illustrated in the following diagram:

• Figure 1-(1): The embedded application acts as an HTTP-client and will connect to your web server to send a GET request to download a firmware update file (myupgrade.gbl). 
• Figure 1-(2): Your server responds with the firmware update file (myupgrade.gbl)
• Figure 1-(3): Once the file myupgrade.gbl is downloaded, the embedded application will store it by using the bootloader interface API to reprogram the bootloader storage area.
• Figure 1-(4): The embedded application will use the bootloader interface API to validate the firmware update image and upgrade the current application.

There are several criteria for the firmware update image to be flashed:

• The file myupgrade.gbl needs to be valid. This is checked by the embedded application using the bootloader interface API. 
• The embedded application checks the version of the firmware update image stored in myupgrade.gbl. If the version of the embedded application is the same or older than the running application, the image file will not be flashed.

The bootloader storage area will be erased, and the embedded application will try to establish a new HTTP/HTTPS connection, if:

• The loaded file is not a valid .gbl image.
• The version of the image stored is the same or older than the running version.
• Anything goes wrong with the HTTP/HTTPS protocol.

Hardware Requirements

• EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A
• Web Server to host the firmware update file

Software Requirements

• Simplicity Studio
• 32-bit MCU SDK
• Micrium OS Kernel
• Micrium OS Network

Getting Started

1. Order an EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A from our website

2. Install Simplicity Studio

• Download and Install the latest version of Simplicity Studio from our website at: http://www.silabs.com/simplicity-studio
• Download the software and follow the installation instructions.
• When asked to sign-in, enter your Silicon Labs username and password. Sign up for a new account if you don’t already have one. This is required to gain access to all of the software components.
• After signing in, register your kit with Simplicity Studio. If the kit is not registered, Simplicity Studio will only enable access to the Micrium Kernel; however, if the kit is registered, Simplicity Studio will enable access to all the other applicable Micrium components as well. The license number is on the box of the kit.

3. Connect the board as shown in the image below:

4. Open Simplicity Studio, from the Launcher perspective, select the example named SLSTK3701A_micriumos_httpcloader as shown below:

5. Open the file httpclient.c located in the /src folder in the Project Explorer and enter the full URL where you plan to host the firmware upgrade image:

#define  FULL_URL   "http://mywebserver.com/myupgrade.gbl"

If your webserver is secured (i.e. https) then this demo includes mbedTLS. Simply make sure that the certificate required by your website is defined in SSL_ROOT_CA[] in the file ssl_certificates.c located in the /src folder of the Project Explorer.

You may also have to tweak the number of bits and bytes that match your website's certificates by setting the proper sizes in MBEDTLS_ECP_MAX_BITS and MBEDTLS_MPI_MAX_SIZE in the configuration file config-ssl-
httpcloader.h located in C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\config-ssl-httpcloader.h

#define MBEDTLS_MPI_MAX_SIZE   256
#define MBEDTLS_ECP_MAX_BITS   384

6. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application to 2 to simulate a firmware upgrade:

#define APP_PROPERTIES_VERSION 2

7. Build the project

8. Generate the firmware upgrade file myupgrade.gbl by opening the utility Simplicity Commander located at C:\SiliconLabs\SimplicityStudio\v4\developer\adapter_packs\commander and by providing the path to your binary file .s37 to a command line similar to this:

commander.exe gbl create myupgrade.gbl --app "C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37"

9. Upload the file myupgrade.gbl to your web server

10. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application back to 1:

#define APP_PROPERTIES_VERSION 1

11. Build the project again

12. Connect the starter kit as previously shown in Figure 2

13. Open Device Manager in Windows to find out the COM Port number of the USB device listed as J-Link CDC UART Port

14. Open a Serial Console application such as PuTTY to see the debug messages during run time

15. Select the item J-Link Silicon Labs from the list of Debug Adapters, right-click to open the context menu and select the option Upload Application... as shown below:

16. In the field Application Image Path, select the file SLSTK3701A_micriumos_httpcloader.s37 that you just built by browsing to the workspace folder where you have your project, a path similar to the following:

C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37

Tick the checkbox to Upload a Bootloader image and select the bootloader that comes with the example by browsing to the file bootloader-storage-internal-single-combined.s37 in a path similar to this:

C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\bootloader-storage-internal-single-combined.s37

17. Press the button Ok to flash both images. The bootloader image will be flashed in a reserved area of Flash and from this point forward you can simply Launch a Debug Session from Simplicity Studio to program the device with a different application image as the bootloader image will be stored in a reserved area of Flash that won't be deleted unless you overwrite it with this tool or from the command line with Simplicity Commander.

18. Watch the serial terminal as the embedded application starts the Ethernet interface, connects to your website to download the file myupgrade.gbl and reboots on the new upgraded embedded application. 

Further Reading

The firmware update situation described in this example assume no authentication and no encryption of the firmware update file. However, these features along with secure boot are supported by our system but it is beyond the scope of this blog.

To sign and encrypt a firmware update file, you can use Simplicity Commander as follows:

commander.exe gbl create --app --bootloader --metadata --compress --encrypt --sign --force

For more information on how to use Simplicity Commander see the section GBL Commands on Page 34 of the following document: 

• UG162: Simplicity Commander Reference Guide: 

https://www.silabs.com/documents/public/user-guides/ug162-simplicity-commander-reference-guide.pdf

For more information on the Gecko Bootloader see the following documents: 

• UG266: Gecko Bootloader User's Guide:

https://www.silabs.com/documents/public/user-guides/ug266-gecko-bootloader-user-guide.pdf

• UG103.6: Bootloader Fundamentals:

https://www.silabs.com/documents/public/user-guides/ug103-06-fundamentals-bootloading.pdf

Introduction

When it comes to IoT device management, over-the-air (OTA) firmware updates play a key role.

OTA enables product manufacturers to remotely update connected devices with bug fixes, feature enhancements and security patches.

If you are evaluating one of our EFM32 32-bit MCUs such as the one onboard the Giant Gecko GG11 Starter Kit (SLSTK3701A) and want to learn a simple way to enable OTA firmware updates then this blog will get you started by presenting the example illustrated in the following diagram:

• Figure 1-(1): The embedded application acts as an HTTP-client and will connect to your web server to send a GET request to download a firmware update file (myupgrade.gbl). 
• Figure 1-(2): Your server responds with the firmware update file (myupgrade.gbl)
• Figure 1-(3): Once the file myupgrade.gbl is downloaded, the embedded application will store it by using the bootloader interface API to reprogram the bootloader storage area.
• Figure 1-(4): The embedded application will use the bootloader interface API to validate the firmware update image and upgrade the current application.

There are several criteria for the firmware update image to be flashed:

• The file myupgrade.gbl needs to be valid. This is checked by the embedded application using the bootloader interface API. 
• The embedded application checks the version of the firmware update image stored in myupgrade.gbl. If the version of the embedded application is the same or older than the running application, the image file will not be flashed.

The bootloader storage area will be erased, and the embedded application will try to establish a new HTTP/HTTPS connection, if:

• The loaded file is not a valid .gbl image.
• The version of the image stored is the same or older than the running version.
• Anything goes wrong with the HTTP/HTTPS protocol.

Hardware Requirements

• EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A
• Web Server to host the firmware update file

Software Requirements

• Simplicity Studio
• 32-bit MCU SDK
• Micrium OS Kernel
• Micrium OS Network

Getting Started

1. Order an EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A from our website

2. Install Simplicity Studio

• Download and Install the latest version of Simplicity Studio from our website at: http://www.silabs.com/simplicity-studio
• Download the software and follow the installation instructions.
• When asked to sign-in, enter your Silicon Labs username and password. Sign up for a new account if you don’t already have one. This is required to gain access to all of the software components.
• After signing in, register your kit with Simplicity Studio. If the kit is not registered, Simplicity Studio will only enable access to the Micrium Kernel; however, if the kit is registered, Simplicity Studio will enable access to all the other applicable Micrium components as well. The license number is on the box of the kit.

3. Connect the board as shown in the image below:

4. Open Simplicity Studio, from the Launcher perspective, select the example named SLSTK3701A_micriumos_httpcloader as shown below:

5. Open the file httpclient.c located in the /src folder in the Project Explorer and enter the full URL where you plan to host the firmware upgrade image:

#define  FULL_URL   "http://mywebserver.com/myupgrade.gbl"

If your webserver is secured (i.e. https) then this demo includes mbedTLS. Simply make sure that the certificate required by your website is defined in SSL_ROOT_CA[] in the file ssl_certificates.c located in the /src folder of the Project Explorer.

You may also have to tweak the number of bits and bytes that match your website's certificates by setting the proper sizes in MBEDTLS_ECP_MAX_BITS and MBEDTLS_MPI_MAX_SIZE in the configuration file config-ssl-
httpcloader.h located in C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\config-ssl-httpcloader.h

#define MBEDTLS_MPI_MAX_SIZE   256
#define MBEDTLS_ECP_MAX_BITS   384

6. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application to 2 to simulate a firmware upgrade:

#define APP_PROPERTIES_VERSION 2

7. Build the project

8. Generate the firmware upgrade file myupgrade.gbl by opening the utility Simplicity Commander located at C:\SiliconLabs\SimplicityStudio\v4\developer\adapter_packs\commander and by providing the path to your binary file .s37 to a command line similar to this:

commander.exe gbl create myupgrade.gbl --app "C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37"

9. Upload the file myupgrade.gbl to your web server

10. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application back to 1:

#define APP_PROPERTIES_VERSION 1

11. Build the project again

12. Connect the starter kit as previously shown in Figure 2

13. Open Device Manager in Windows to find out the COM Port number of the USB device listed as J-Link CDC UART Port

14. Open a Serial Console application such as PuTTY to see the debug messages during run time

15. Select the item J-Link Silicon Labs from the list of Debug Adapters, right-click to open the context menu and select the option Upload Application... as shown below:

16. In the field Application Image Path, select the file SLSTK3701A_micriumos_httpcloader.s37 that you just built by browsing to the workspace folder where you have your project, a path similar to the following:

C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37

Tick the checkbox to Upload a Bootloader image and select the bootloader that comes with the example by browsing to the file bootloader-storage-internal-single-combined.s37 in a path similar to this:

C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\bootloader-storage-internal-single-combined.s37

17. Press the button Ok to flash both images. The bootloader image will be flashed in a reserved area of Flash and from this point forward you can simply Launch a Debug Session from Simplicity Studio to program the device with a different application image as the bootloader image will be stored in a reserved area of Flash that won't be deleted unless you overwrite it with this tool or from the command line with Simplicity Commander.

18. Watch the serial terminal as the embedded application starts the Ethernet interface, connects to your website to download the file myupgrade.gbl and reboots on the new upgraded embedded application. 

Further Reading

The firmware update situation described in this example assume no authentication and no encryption of the firmware update file. However, these features along with secure boot are supported by our system but it is beyond the scope of this blog.

To sign and encrypt a firmware update file, you can use Simplicity Commander as follows:

commander.exe gbl create --app --bootloader --metadata --compress --encrypt --sign --force

For more information on how to use Simplicity Commander see the section GBL Commands on Page 34 of the following document: 

• UG162: Simplicity Commander Reference Guide: 

https://www.silabs.com/documents/public/user-guides/ug162-simplicity-commander-reference-guide.pdf

For more information on the Gecko Bootloader see the following documents: 

• UG266: Gecko Bootloader User's Guide:

https://www.silabs.com/documents/public/user-guides/ug266-gecko-bootloader-user-guide.pdf

• UG103.6: Bootloader Fundamentals:

https://www.silabs.com/documents/public/user-guides/ug103-06-fundamentals-bootloading.pdf

Introduction

When it comes to IoT device management, over-the-air (OTA) firmware updates play a key role.

OTA enables product manufacturers to remotely update connected devices with bug fixes, feature enhancements and security patches.

If you are evaluating one of our EFM32 32-bit MCUs such as the one onboard the Giant Gecko GG11 Starter Kit (SLSTK3701A) and want to learn a simple way to enable OTA firmware updates then this blog will get you started by presenting the example illustrated in the following diagram:

• Figure 1-(1): The embedded application acts as an HTTP-client and will connect to your web server to send a GET request to download a firmware update file (myupgrade.gbl). 
• Figure 1-(2): Your server responds with the firmware update file (myupgrade.gbl)
• Figure 1-(3): Once the file myupgrade.gbl is downloaded, the embedded application will store it by using the bootloader interface API to reprogram the bootloader storage area.
• Figure 1-(4): The embedded application will use the bootloader interface API to validate the firmware update image and upgrade the current application.

There are several criteria for the firmware update image to be flashed:

• The file myupgrade.gbl needs to be valid. This is checked by the embedded application using the bootloader interface API. 
• The embedded application checks the version of the firmware update image stored in myupgrade.gbl. If the version of the embedded application is the same or older than the running application, the image file will not be flashed.

The bootloader storage area will be erased, and the embedded application will try to establish a new HTTP/HTTPS connection, if:

• The loaded file is not a valid .gbl image.
• The version of the image stored is the same or older than the running version.
• Anything goes wrong with the HTTP/HTTPS protocol.

Hardware Requirements

• EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A
• Web Server to host the firmware update file

Software Requirements

• Simplicity Studio
• 32-bit MCU SDK
• Micrium OS Kernel
• Micrium OS Network

Getting Started

1. Order an EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A from our website

2. Install Simplicity Studio

• Download and Install the latest version of Simplicity Studio from our website at: http://www.silabs.com/simplicity-studio
• Download the software and follow the installation instructions.
• When asked to sign-in, enter your Silicon Labs username and password. Sign up for a new account if you don’t already have one. This is required to gain access to all of the software components.
• After signing in, register your kit with Simplicity Studio. If the kit is not registered, Simplicity Studio will only enable access to the Micrium Kernel; however, if the kit is registered, Simplicity Studio will enable access to all the other applicable Micrium components as well. The license number is on the box of the kit.

3. Connect the board as shown in the image below:

4. Open Simplicity Studio, from the Launcher perspective, select the example named SLSTK3701A_micriumos_httpcloader as shown below:

5. Open the file httpclient.c located in the /src folder in the Project Explorer and enter the full URL where you plan to host the firmware upgrade image:

#define  FULL_URL   "http://mywebserver.com/myupgrade.gbl"

If your webserver is secured (i.e. https) then this demo includes mbedTLS. Simply make sure that the certificate required by your website is defined in SSL_ROOT_CA[] in the file ssl_certificates.c located in the /src folder of the Project Explorer.

You may also have to tweak the number of bits and bytes that match your website's certificates by setting the proper sizes in MBEDTLS_ECP_MAX_BITS and MBEDTLS_MPI_MAX_SIZE in the configuration file config-ssl-
httpcloader.h located in C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\config-ssl-httpcloader.h

#define MBEDTLS_MPI_MAX_SIZE   256
#define MBEDTLS_ECP_MAX_BITS   384

6. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application to 2 to simulate a firmware upgrade:

#define APP_PROPERTIES_VERSION 2

7. Build the project

8. Generate the .gbl file by opening the utility Simplicity Commander located at C:\SiliconLabs\SimplicityStudio\v4\developer\adapter_packs\commander and issuing the following command:

commander.exe gbl create myupgrade.gbl --app "C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37"

9. Upload the file myupgrade.gbl to your web server

10. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application back to 1:

#define APP_PROPERTIES_VERSION 1

11. Build the project again

12. Connect the starter kit as previously shown in Figure 2

13. Open Device Manager in Windows to find out the COM Port number of the USB device listed as J-Link CDC UART Port

14. Open a Serial Console application such as PuTTY to see the debug messages during run time

15. Select the item J-Link Silicon Labs from the list of Debug Adapters, right-click to open the context menu and select the option Upload Application... as shown below:

16. In the field Application Image Path, select the file SLSTK3701A_micriumos_httpcloader.s37 that you just built by browsing to the workspace folder where you have your project, a path similar to the following:

C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37

Tick the checkbox to Upload a Bootloader image and select the bootloader that comes with the example by browsing to the file bootloader-storage-internal-single-combined.s37 in a path similar to this:

C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\bootloader-storage-internal-single-combined.s37

17. Press the button Ok to flash both images. The bootloader image will be flashed in a reserved area of Flash and from this point forward you can simply Launch a Debug Session from Simplicity Studio to program the device with a different application image as the bootloader image will be stored in a reserved area of Flash that won't be deleted unless you overwrite it with this tool or from the command line with Simplicity Commander.

18. Watch the serial terminal as the embedded application starts the Ethernet interface, connects to your website to download the file myupgrade.gbl and reboots on the new upgraded embedded application. 

Further Reading

The firmware update situation described in this example assume no authentication and no encryption of the firmware update file. However, these features along with secure boot are supported by our system but it is beyond the scope of this blog.

To sign and encrypt a firmware update file, you can use Simplicity Commander as follows:

commander.exe gbl create --app --bootloader --metadata --compress --encrypt --sign --force

For more information on how to use Simplicity Commander see the section GBL Commands on Page 34 of the following document: 

• UG162: Simplicity Commander Reference Guide: 

https://www.silabs.com/documents/public/user-guides/ug162-simplicity-commander-reference-guide.pdf

For more information on the Gecko Bootloader see the following documents: 

• UG266: Gecko Bootloader User's Guide:

https://www.silabs.com/documents/public/user-guides/ug266-gecko-bootloader-user-guide.pdf

• UG103.6: Bootloader Fundamentals:

https://www.silabs.com/documents/public/user-guides/ug103-06-fundamentals-bootloading.pdf

Introduction

When it comes to IoT device management, over-the-air (OTA) firmware updates play a key role.

OTA enables product manufacturers to remotely update connected devices with bug fixes, feature enhancements and security patches.

If you are evaluating one of our EFM32 32-bit MCUs such as the one onboard the Giant Gecko GG11 Starter Kit (SLSTK3701A) and want to learn a simple way to enable OTA firmware updates then this blog will get you started by presenting the example illustrated in the following diagram:

• Figure 1-(1): The embedded application acts as an HTTP-client and will connect to your web server to send a GET request to download a firmware update file (myupgrade.gbl). 
• Figure 1-(2): Your server responds with the firmware update file (myupgrade.gbl)
• Figure 1-(3): Once the file myupgrade.gbl is downloaded, the embedded application will store it by using the bootloader interface API to reprogram the bootloader storage area.
• Figure 1-(4): The embedded application will use the bootloader interface API to validate the firmware update image and upgrade the current application.

There are several criteria for the firmware update image to be flashed:

• The file myupgrade.gbl needs to be valid. This is checked by the embedded application using the bootloader interface API. 
• The embedded application checks the version of the firmware update image stored in myupgrade.gbl. If the version of the embedded application is the same or older than the running application, the image file will not be flashed.

The bootloader storage area will be erased, and the embedded application will try to establish a new HTTP/HTTPS connection, if:

• The loaded file is not a valid .gbl image.
• The version of the image stored is the same or older than the running version.
• Anything goes wrong with the HTTP/HTTPS protocol.

Hardware Requirements

• EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A
• Web Server to host the firmware update file

Software Requirements

• Simplicity Studio
• 32-bit MCU SDK
• Micrium OS Kernel
• Micrium OS Network

Getting Started

1. Order an EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A from our website

2. Install Simplicity Studio

• Download and Install the latest version of Simplicity Studio from our website at: http://www.silabs.com/simplicity-studio
• Download the software and follow the installation instructions.
• When asked to sign-in, enter your Silicon Labs username and password. Sign up for a new account if you don’t already have one. This is required to gain access to all of the software components.
• After signing in, register your kit with Simplicity Studio. If the kit is not registered, Simplicity Studio will only enable access to the Micrium Kernel; however, if the kit is registered, Simplicity Studio will enable access to all the other applicable Micrium components as well. The license number is on the box of the kit.

3. Connect the board as shown in the image below:

4. Open Simplicity Studio, from the Launcher perspective, select the example named SLSTK3701A_micriumos_httpcloader as shown below:

5. Open the file httpclient.c located in the /src folder in the Project Explorer and enter the full URL where you plan to host the firmware upgrade image:

#define  FULL_URL   "http://mywebserver.com/myupgrade.gbl"

If your webserver is secured (i.e. https) then this demo includes mbedTLS. Simply make sure that the certificate required by your website is defined in SSL_ROOT_CA[] in the file ssl_certificates.c located in the /src folder of the Project Explorer.

You may also have to tweak the number of bits and bytes that match your website's certificates by setting the proper sizes in MBEDTLS_ECP_MAX_BITS and MBEDTLS_MPI_MAX_SIZE in the configuration file config-ssl-
httpcloader.h located in C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\config-ssl-httpcloader.h

#define MBEDTLS_MPI_MAX_SIZE   256
#define MBEDTLS_ECP_MAX_BITS   384

6. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application to 2 to simulate a firmware upgrade:

#define APP_PROPERTIES_VERSION 2

7. Build the project

8. Generate the .gbl file by opening the utility Simplicity Commander located at C:\SiliconLabs\SimplicityStudio\v4\developer\adapter_packs\commander and issuing the following command:

commander.exe gbl create myupgrade.gbl --app "C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37"

9. Upload the file myupgrade.gbl to your web server

10. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application back to 1:

#define APP_PROPERTIES_VERSION 1

11. Build the project again

12. Connect the starter kit as previously shown in Figure 2

13. Open Device Manager in Windows to find out the COM Port number of the USB device listed as J-Link CDC UART Port

14. Open a Serial Console application such as PuTTY to see the debug messages during run time

15. Select the item J-Link Silicon Labs from the list of Debug Adapters, right-click to open the context menu and select the option Upload Application... as shown below:

16. In the field Application Image Path, select the file SLSTK3701A_micriumos_httpcloader.s37 that you just built by browsing to the workspace folder where you have your project, a path similar to the following:

C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37

Tick the checkbox to Upload a Bootloader image and select the bootloader that comes with the example by browsing to the file bootloader-storage-internal-single-combined.s37 in a path similar to this:

C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\bootloader-storage-internal-single-combined.s37

17. Press the button Ok to flash both images. The bootloader image will be flashed in a reserved area of Flash and from this point forward you can simply Launch a Debug Session from Simplicity Studio to program the device with a different application image as the bootloader image will be stored in a reserved area of Flash that won't be deleted unless you overwrite it with this tool or from the command line with Simplicity Commander.

18. Watch the serial terminal as the embedded application starts the Ethernet interface, connects to your website to download the file myupgrade.gbl and reboots on the new upgraded embedded application. 

Further Reading

The firmware update situation described in this example assume no authentication and no encryption of the firmware update file. However, these features along with secure boot are supported by our system but it is beyond the scope of this blog.

To sign and encrypt a firmware update file, you can use Simplicity Commander as follows:

commander.exe gbl create --app --bootloader --metadata --compress --encrypt --sign --force

For more information on how to use Simplicity Commander see the section GBL Commands on Page 34 of the following document: 

• UG162: Simplicity Commander Reference Guide: 

https://www.silabs.com/documents/public/user-guides/ug162-simplicity-commander-reference-guide.pdf

For more information on the Gecko Bootloader see the following documents: 

• UG266: Gecko Bootloader User's Guide:

https://www.silabs.com/documents/public/user-guides/ug266-gecko-bootloader-user-guide.pdf

• UG103.6: Bootloader Fundamentals:

https://www.silabs.com/documents/public/user-guides/ug103-06-fundamentals-bootloading.pdf

Introduction

When it comes to IoT device management, over-the-air (OTA) firmware updates play a key role.

OTA enables product manufacturers to remotely update connected devices with bug fixes, feature enhancements and security patches.

If you are evaluating one of our EFM32 32-bit MCUs such as the one onboard the Giant Gecko GG11 Starter Kit (SLSTK3701A) and want to learn a simple way to enable OTA firmware updates then this blog will get you started by presenting the example illustrated in the following diagram:

• Figure 1-(1): The embedded application acts as an HTTP-client and will connect to your web server to send a GET request to download a firmware update file (myupgrade.gbl). 
• Figure 1-(2): Your server responds with the firmware update file (myupgrade.gbl)
• Figure 1-(3): Once the file myupgrade.gbl is downloaded, the embedded application will store it by using the bootloader interface API to reprogram the bootloader storage area.
• Figure 1-(4): The embedded application will use the bootloader interface API to validate the firmware update image and upgrade the current application.

There are several criteria for the firmware update image to be flashed:

• The file myupgrade.gbl needs to be valid. This is checked by the embedded application using the bootloader interface API. 
• The embedded application checks the version of the firmware update image stored in myupgrade.gbl. If the version of the embedded application is the same or older than the running application, the image file will not be flashed.

The bootloader storage area will be erased, and the embedded application will try to establish a new HTTP/HTTPS connection, if:

• The loaded file is not a valid .gbl image.
• The version of the image stored is the same or older than the running version.
• Anything goes wrong with the HTTP/HTTPS protocol.

Hardware Requirements

• EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A
• Web Server to host the firmware update file

Software Requirements

• Simplicity Studio
• 32-bit MCU SDK
• Micrium OS Kernel
• Micrium OS Network

Getting Started

1. Order an EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A from our website

2. Install Simplicity Studio

• Download and Install the latest version of Simplicity Studio from our website at: http://www.silabs.com/simplicity-studio
• Download the software and follow the installation instructions.
• When asked to sign-in, enter your Silicon Labs username and password. Sign up for a new account if you don’t already have one. This is required to gain access to all of the software components.
• After signing in, register your kit with Simplicity Studio. If the kit is not registered, Simplicity Studio will only enable access to the Micrium Kernel; however, if the kit is registered, Simplicity Studio will enable access to all the other applicable Micrium components as well. The license number is on the box of the kit.

3. Connect the board as shown in the image below:

4. Open Simplicity Studio, from the Launcher perspective, select the example named SLSTK3701A_micriumos_httpcloader as shown below:

5. Open the file httpclient.c located in the /src folder in the Project Explorer and enter the full URL where you plan to host the firmware upgrade image:

#define  FULL_URL   "http://mywebserver.com/myupgrade.gbl"

If your webserver is secured (i.e. https) then this demo includes mbedTLS. Simply make sure that the certificate required by your website is defined in SSL_ROOT_CA[] in the file ssl_certificates.c located in the /src folder of the Project Explorer.

You may also have to tweak the number of bits and bytes that match your website's certificates by setting the proper sizes in MBEDTLS_ECP_MAX_BITS and MBEDTLS_MPI_MAX_SIZE in the configuration file config-ssl-
httpcloader.h located in C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\config-ssl-httpcloader.h

#define MBEDTLS_MPI_MAX_SIZE   256
#define MBEDTLS_ECP_MAX_BITS   384

6. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application to 2 to simulate a firmware upgrade:

#define APP_PROPERTIES_VERSION 2

7. Build the project

8. Generate the .gbl file by opening the utility Simplicity Commander located at C:\SiliconLabs\SimplicityStudio\v4\developer\adapter_packs\commander and issuing the following command:

commander.exe gbl create myupgrade.gbl --app "C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37"

9. Upload the file myupgrade.gbl to your web server

10. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application back to 1:

#define APP_PROPERTIES_VERSION 1

11. Build the project again

12. Connect the starter kit as previously shown in Figure 2

13. Open Device Manager in Windows to find out the COM Port number of the USB device listed as J-Link CDC UART Port

14. Open a Serial Console application such as PuTTY to see the debug messages during run time

15. Select the item J-Link Silicon Labs from the list of Debug Adapters, right-click to open the context menu and select the option Upload Application... as shown below:

16. In the field Application Image Path, select the file SLSTK3701A_micriumos_httpcloader.s37 that you just built by browsing to the workspace folder where you have your project, a path similar to the following:

C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37

Tick the checkbox to Upload a Bootloader image and select the bootloader that comes with the example by browsing to the file bootloader-storage-internal-single-combined.s37 in a path similar to this:

C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\bootloader-storage-internal-single-combined.s37

17. Press the button Ok to flash both images. The bootloader image will be flashed in a reserved area of Flash and from this point forward you can simply Launch a Debug Session from Simplicity Studio to program the device with a different application image as the bootloader image will be stored in a reserved area of Flash that won't be deleted unless you overwrite it with this tool or from the command line with Simplicity Commander.

18. Watch the serial terminal as the embedded application starts the Ethernet interface, connects to your website to download the file myupgrade.gbl and reboots on the new upgraded embedded application. 

Further Reading

The firmware update situation described in this example assume no authentication and no encryption of the firmware update file. However, these features along with secure boot are supported by our system but it is beyond the scope of this blog.

To sign and encrypt a firmware update file, you can use Simplicity Commander as follows:

commander.exe gbl create --app --bootloader --metadata --compress --encrypt --sign --force

For more information on how to use Simplicity Commander see the section GBL Commands on Page 34 of the following document: https://www.silabs.com/documents/public/user-guides/ug162-simplicity-commander-reference-guide.pdf

For more information on the Gecko Bootloader see the following document: https://www.silabs.com/documents/public/user-guides/ug266-gecko-bootloader-user-guide.pdf

Introduction

When it comes to IoT device management, over-the-air (OTA) firmware updates play a key role.

OTA enables product manufacturers to remotely update connected devices with bug fixes, feature enhancements and security patches.

If you are evaluating one of our EFM32 32-bit MCUs such as the one onboard the Giant Gecko GG11 Starter Kit (SLSTK3701A) and want to learn a simple way to enable OTA firmware updates then this blog will get you started by presenting the example illustrated in the following diagram:

• Figure 1-(1): The embedded application acts as an HTTP-client and will connect to your web server to send a GET request to download a firmware update file (myupgrade.gbl). 
• Figure 1-(2): Your server responds with the firmware update file (myupgrade.gbl)
• Figure 1-(3): Once the file myupgrade.gbl is downloaded, the embedded application will store it by using the bootloader interface API to reprogram the bootloader storage area.
• Figure 1-(4): The embedded application will use the bootloader interface API to validate the firmware update image and upgrade the current application.

There are several criteria for the firmware update image to be flashed:

• The file myupgrade.gbl needs to be valid. This is checked by the embedded application using the bootloader interface API. 
• The embedded application checks the version of the firmware update image stored in myupgrade.gbl. If the version of the embedded application is the same or older than the running application, the image file will not be flashed.

The bootloader storage area will be erased, and the embedded application will try to establish a new HTTP/HTTPS connection, if:

• The loaded file is not a valid .gbl image.
• The version of the image stored is the same or older than the running version.
• Anything goes wrong with the HTTP/HTTPS protocol.

Hardware Requirements

• EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A
• Web Server to host the firmware update file

Software Requirements

• Simplicity Studio
• 32-bit MCU SDK
• Micrium OS Kernel
• Micrium OS Network

Getting Started

1. Order an EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A from our website

2. Install Simplicity Studio

• Download and Install the latest version of Simplicity Studio from our website at: http://www.silabs.com/simplicity-studio
• Download the software and follow the installation instructions.
• When asked to sign-in, enter your Silicon Labs username and password. Sign up for a new account if you don’t already have one. This is required to gain access to all of the software components.
• After signing in, register your kit with Simplicity Studio. If the kit is not registered, Simplicity Studio will only enable access to the Micrium Kernel; however, if the kit is registered, Simplicity Studio will enable access to all the other applicable Micrium components as well. The license number is on the box of the kit.

3. Connect the board as shown in the image below:

4. Open Simplicity Studio, from the Launcher perspective, select the example named SLSTK3701A_micriumos_httpcloader as shown below:

5. Open the file httpclient.c located in the /src folder in the Project Explorer and enter the full URL where you plan to host the firmware upgrade image:

#define  FULL_URL   "http://mywebserver.com/myupgrade.gbl"

If your webserver is secured (i.e. https) then this demo includes mbedTLS. Simply make sure that the certificate required by your website is defined in SSL_ROOT_CA[] in the file ssl_certificates.c located in the /src folder of the Project Explorer.

You may also have to tweak the number of bits and bytes that match your website's certificates by setting the proper sizes in MBEDTLS_ECP_MAX_BITS and MBEDTLS_MPI_MAX_SIZE in the configuration file config-ssl-
httpcloader.h located in C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\config-ssl-httpcloader.h

#define MBEDTLS_MPI_MAX_SIZE   256
#define MBEDTLS_ECP_MAX_BITS   384

6. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application to 2 to simulate a firmware upgrade:

#define APP_PROPERTIES_VERSION 2

7. Build the project

8. Generate the .gbl file by opening the utility Simplicity Commander located at C:\SiliconLabs\SimplicityStudio\v4\developer\adapter_packs\commander and issuing the following command:

commander.exe gbl create myupgrade.gbl --app "C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37"

9. Upload the file myupgrade.gbl to your web server

10. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application back to 1:

#define APP_PROPERTIES_VERSION 1

11. Build the project again

12. Connect the starter kit as previously shown in Figure 2

13. Open Device Manager in Windows to find out the COM Port number of the USB device listed as J-Link CDC UART Port

14. Open a Serial Console application such as PuTTY to see the debug messages during run time

15. Select the item J-Link Silicon Labs from the list of Debug Adapters, right-click to open the context menu and select the option Upload Application... as shown below:

16. In the field Application Image Path, select the file SLSTK3701A_micriumos_httpcloader.s37 that you just built by browsing to the workspace folder where you have your project, a path similar to the following:

C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37

Tick the checkbox to Upload a Bootloader image and select the bootloader that comes with the example by browsing to the file bootloader-storage-internal-single-combined.s37 in a path similar to this:

C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\bootloader-storage-internal-single-combined.s37

17. Press the button Ok to flash both images. The bootloader image will be flashed in a reserved area of Flash and from this point forward you can simply Launch a Debug Session from Simplicity Studio to program the device with a different application image as the bootloader image will be stored in a reserved area of Flash that won't be deleted unless you overwrite it with this tool or from the command line with Simplicity Commander.

18. Watch the serial terminal as the embedded application starts the Ethernet interface, connects to your website to download the file myupgrade.gbl and reboots on the new upgraded embedded application. 

Further Reading

The firmware update situation described in this example assume no authentication and no encryption of the firmware update file. However, these features along with secure boot are supported by our system but it is beyond the scope of this blog.

To sign and encrypt a firmware update file, you can use Simplicity Commander as follows:

commander.exe gbl create --app --bootloader --metadata --compress --encrypt --sign --force

For more information on how to use Simplicity Commander see the section GBL Commands on Page 34 of the following document: https://www.silabs.com/documents/public/user-guides/ug162-simplicity-commander-reference-guide.pdf

For more information on the Gecko Bootloader see the following document: https://www.silabs.com/documents/public/user-guides/ug266-gecko-bootloader-user-guide.pdf

Introduction

When it comes to IoT device management, over-the-air (OTA) firmware updates play a key role.

OTA enables product manufacturers to remotely update connected devices with bug fixes, feature enhancements and security patches.

If you are evaluating one of our EFM32 32-bit MCUs such as the one onboard the Giant Gecko GG11 Starter Kit (SLSTK3701A) and want to learn a simple way to enable OTA firmware updates then this blog will get you started by presenting the example illustrated in the following diagram:

• Figure 1-(1): The embedded application acts as an HTTP-client and will connect to your web server to send a GET request to download a firmware update file (myupgrade.gbl). 
• Figure 1-(2): Your server responds with the firmware update file (myupgrade.gbl)
• Figure 1-(3): Once the file myupgrade.gbl is downloaded, the embedded application will store it by using the bootloader interface API to reprogram the bootloader storage area.
• Figure 1-(4): The embedded application will use the bootloader interface API to validate the firmware update image and upgrade the current application.

There are several criteria for the firmware update image to be flashed:

• The file myupgrade.gbl needs to be valid. This is checked by the embedded application using the bootloader interface API. 
• The embedded application checks the version of the firmware update image stored in myupgrade.gbl. If the version of the embedded application is the same or older than the running application, the image file will not be flashed.

The bootloader storage area will be erased, and the embedded application will try to establish a new HTTP/HTTPS connection, if:

• The loaded file is not a valid .gbl image.
• The version of the image stored is the same or older than the running version.
• Anything goes wrong with the HTTP/HTTPS protocol.

Hardware Requirements

• EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A
• Web Server to host the firmware update file

Software Requirements

• Simplicity Studio
• 32-bit MCU SDK
• Micrium OS Kernel
• Micrium OS Network

Getting Started

1. Order an EFM32 Giant Gecko GG11 Starter Kit SLSTK3701A from our website

2. Install Simplicity Studio

• Download and Install the latest version of Simplicity Studio from our website at: http://www.silabs.com/simplicity-studio
• Download the software and follow the installation instructions.
• When asked to sign-in, enter your Silicon Labs username and password. Sign up for a new account if you don’t already have one. This is required to gain access to all of the software components.
• After signing in, register your kit with Simplicity Studio. If the kit is not registered, Simplicity Studio will only enable access to the Micrium Kernel; however, if the kit is registered, Simplicity Studio will enable access to all the other applicable Micrium components as well. The license number is on the box of the kit.

3. Connect the board as shown in the image below:

4. Open Simplicity Studio, from the Launcher perspective, select the example named SLSTK3701A_micriumos_httpcloader as shown below:

5. Open the file httpclient.c located in the /src folder in the Project Explorer and enter the full URL where you plan to host the firmware upgrade image:

#define  FULL_URL   "http://mywebserver.com/myupgrade.gbl"

If your webserver is secured (i.e. https) then this demo includes mbedTLS. Simply make sure that the certificate required by your website is defined in SSL_ROOT_CA[] in the file ssl_certificates.c located in the /src folder of the Project Explorer.

You may also have to tweak the number of bits and bytes that match your website's certificates by setting the proper sizes in MBEDTLS_ECP_MAX_BITS and MBEDTLS_MPI_MAX_SIZE in the configuration file config-ssl-
httpcloader.h located in C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\config-ssl-httpcloader.h

#define MBEDTLS_MPI_MAX_SIZE   256
#define MBEDTLS_ECP_MAX_BITS   384

6. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application to 2 to simulate a firmware upgrade:

#define APP_PROPERTIES_VERSION 2

7. Build the project

8. Generate the .gbl file by opening the utility Simplicity Commander located at C:\SiliconLabs\SimplicityStudio\v4\developer\adapter_packs\commander and issuing the following command:

commander.exe gbl create myupgrade.gbl --app "C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37"

9. Upload the file myupgrade.gbl to your web server

10. Open the file application_properties.c in the /src folder of the Project Explorer and set the version number of the embedded application back to 1:

#define APP_PROPERTIES_VERSION 1

11. Build the project again

12. Connect the starter kit as previously shown in Figure 2

13. Open Device Manager in Windows to find out the COM Port number of the USB device listed as J-Link CDC UART Port

14. Open a Serial Console application such as PuTTY to see the debug messages during run time

15. Select the item J-Link Silicon Labs from the list of Debug Adapters, right-click to open the context menu and select the option Upload Application... as shown below:

16. In the field Application Image Path, select the file SLSTK3701A_micriumos_httpcloader.s37 that you just built by browsing to the workspace folder where you have your project, a path similar to the following:

C:\Users\[YourUsername]\SimplicityStudio\v4_workspace\SLSTK3701A_micriumos_httpcloader\GNU ARM v7.2.1 - Debug\SLSTK3701A_micriumos_httpcloader.s37

Tick the checkbox to Upload a Bootloader image and select the bootloader that comes with the example by browsing to the file bootloader-storage-internal-single-combined.s37 in a path similar to this:

C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.5\app\mcu_example\SLSTK3701A_EFM32GG11\micriumos_httpcloader\bootloader-storage-internal-single-combined.s37

17. Press the button Ok to flash both images. The bootloader image will be flashed in a reserved area of Flash and from this point forward you can simply Launch a Debug Session from Simplicity Studio to program the device with a different application image as the bootloader image will be stored in a reserved area of Flash that won't be deleted unless you overwrite it with this tool or from the command line with Simplicity Commander.

18. Watch the serial terminal as the embedded application starts the Ethernet interface, connects to your website to download the file myupgrade.gbl and reboots on the new upgraded embedded application. 

Further Reading

The firmware update situation described in this example assume no authentication and no encryption of the firmware update file. However, these features along with secure boot are supported by our system but it is beyond the scope of this blog.

To sign and encrypt a firmware update file, you can use Simplicity Commander as follows:

commander.exe gbl create --app --bootloader --metadata --compress --encrypt --sign --force

For more information on how to use Simplicity Commander see the section GBL Commands on Page 34 of the following document: https://www.silabs.com/documents/public/user-guides/ug162-simplicity-commander-reference-guide.pdf

For more information on the Gecko Bootloader see the following document: https://www.silabs.com/documents/public/user-guides/ug266-gecko-bootloader-user-guide.pdf