Replace S132 with S112

Question

My application is a BLE peripheral and will only allow a single connection to a BLE central. Hardware will be nRF52832. My test application was based on a Nordic example that uses S132. It looks like I could save some flash if I use S112 instead of S132. Would this work and is this a good choice.

AndreasF · Accepted Answer

Hi.

Sorry for the late reply, I tried to answer you yesterday, but the reply got very long, so here it is today.

I can try to clarify more:

If you have a bootloader and an application you wish to use for a DFU, the right settings for this DFU .zip file must be given when you create it.

With that in background, there should not be any issues if your application runs standalone, and your bootloader also runs standalone, to use this application as the upgrade firmware. But, if the DFU Packet is generated with the wrong settings, the bootloader will have a bad time running the application. It might not know what the application start address is, or the end address. Since this is dependent on the SoftDevice. Therefore, it is essential that if you wish to do a DFU where you change SoftDevice version you include this when you generate the DFU packet. Also, if the SoftDevice version is to be changed, a bootloader with the SoftDevice version of the new firmware is required.

So, I will try to walk you through the process a bit more:

To do a DFU where we change the applications SoftDevice we require 3 items in our DFU packet:

Bootloader with SoftDevice S112 v6.1.0
Application with SoftDevice S112 v6.1.0
SoftDevice S112 v6.1.0

We also need a bootloader with SoftDevice S132 v6.1.0.

So lets start.

Bootloader with SoftDevice S132 v6.1.0

I used the bootloader project found in nRF5_SDK_15.2.0_9412b96\examples\dfu\secure_bootloader\pca10040_ble

You need to have a key which you use to verify the DFU packet.

This can be created by doing the following, which is explained on the infocenter:

Use the nrfutil command:

nrfutil keys generate private.pem

In a command window. This command will create a key file.

Open the bootloader project. And create a new file called dfu_public_key.c in the Application folder, if its there already you dont have to create a new one.

Use the nrfutil command:

nrfutil keys display --key pk --format code private.pem

To display the content of the key file in your command window, like this:

You should now copy the output from the keys display command and replace it with the existing code in dfu_public_key.c, In my case this was the code I pasted and replaced the code in dfu_public_key.c:

/* This file was automatically generated by nrfutil on 2018-11-29 (YY-MM-DD) at 14:43:06 */

#include "sdk_config.h"
#include "stdint.h"
#include "compiler_abstraction.h"

#if NRF_CRYPTO_BACKEND_OBERON_ENABLED
/* Oberon backend is changing endianness thus public key must be kept in RAM. */
#define _PK_CONST
#else
#define _PK_CONST const
#endif


/** @brief Public key used to verify DFU images */
__ALIGN(4) _PK_CONST uint8_t pk[64] =
{
    0xb4, 0xbf, 0x71, 0x80, 0x25, 0x9f, 0x6c, 0xaf, 0x88, 0xd5, 0xfd, 0x03, 0xcf, 0x64, 0xa1, 0x87, 0xef, 0x79, 0xf0, 0x4f, 0xf1, 0x63, 0x36, 0x23, 0xea, 0xd9, 0xff, 0x9f, 0xc9, 0xd9, 0x92, 0x3d,
    0x88, 0xa6, 0xd1, 0xf2, 0x7f, 0xd6, 0xbc, 0x6d, 0x83, 0x78, 0xb7, 0xc7, 0xd3, 0xb1, 0xb3, 0xbe, 0x73, 0x5c, 0x3f, 0x89, 0xd5, 0xbe, 0x39, 0x07, 0xed, 0x2f, 0x25, 0xa4, 0xc2, 0xc7, 0x65, 0x68
};

NOTE: Do not use the code I have pasted here, you have to use the code generated from your own key.

You can now compile the project, and the project should compile without errors. You have no made a bootloader which requires a private key, and the bootloader is using SoftDevice S132 v6.1.0.

2. Create the Application which uses SoftDevice S112 v6.1.0

I used the UART example project, but you can use whatever you like

I just compiled the project found in the folder nRF5_SDK_15.2.0_9412b96\examples\ble_peripheral\ble_app_uart\pca10040\s112

The projects found in pca10040\s112 folders are setup for nRF52832 Boards and uses SoftDevice S112 v6.1.0.

If you would like to use a project which does not have a pca10040\s112 folder, you have to set this up yourself by doing the following:

Copy the pca10040\s132 folder, and open your preferred IDE and do the following modifications:

1. Change two of the include paths from:

../../../../../../components/softdevice/s132/headers
../../../../../../components/softdevice/s132/headers/nrf52

To:

../../../../../../components/softdevice/s112/headers

../../../../../../components/softdevice/s112/headers/nrf52

2. Change the SoftDevice included to:

nRF5_SDK_15.2.0_9412b96/components/softdevice/s112/hex/s112_nrf52_6.1.0_softdevice.hex

3. Edit the preprocessor definition S132 to S112

4. Edit the Section Placement Macros to:

FLASH_PH_START=0x0

FLASH_PH_SIZE=0x80000

RAM_PH_START=0x20000000

RAM_PH_SIZE=0x10000

FLASH_START=0x19000

FLASH_SIZE=0x67000

RAM_START=0x20002500

RAM_SIZE=0xdb00

It should now compile without any errors

3. Create the Bootloader which uses SoftDevice S112 v6.1.0

Here, I used the secure_bootloader project (nRF5_SDK_15.2.0_9412b96\examples\dfu\secure_bootloader\pca10040_ble) and did the same thing as I would have done above if I had used a project which did not have a pca10040\s112 folder, That is:

Copy the pca10040\s132 folder, and open your preferred IDE and do the following modifications:

1. Changed two of the include paths from:

../../../../../../components/softdevice/s132/headers
../../../../../../components/softdevice/s132/headers/nrf52

To:

../../../../../../components/softdevice/s112/headers

../../../../../../components/softdevice/s112/headers/nrf52

2. Changed the SoftDevice included to:

nRF5_SDK_15.2.0_9412b96/components/softdevice/s112/hex/s112_nrf52_6.1.0_softdevice.hex

3. Edit the preprocessor definition S132 to S112

4. Edit the Section Placement Macros to:

FLASH_PH_START=0x0

FLASH_PH_SIZE=0x80000

RAM_PH_START=0x20000000

RAM_PH_SIZE=0x10000

FLASH_START=0x19000

FLASH_SIZE=0x67000

RAM_START=0x20002500

RAM_SIZE=0xdb00

It should now compile without any errors

Create the DFU packet

Make sure you have the latest nrfutil, by running the command pip install nrfutil in your preferred command window.

I use the information about generating a DFU packet found on the infocenter to write the following command:

nrfutil pkg generate --hw-version 52 --sd-req 0xAF,0xB0 --application-version 4 --application <application_hex_file_name>.hex --softdevice s112_nrf52_6.1.0_softdevice.hex --bootloader <bootloader_with_s112v6.1.0_hex_file_name>.hex  --bootloader-version 2 --sd-id 0xB0 --key-file private.pem <dfu_packet_name>.zip

This command gave me this output:

I opened the nRF Connect Bluetooth Low Energy Application and connected to the bootloader DfuTarg, and clicked on the DFU button, selected the file and started:

Start of transfer:

During transfer:

Completed:

And after I've completed the transfer, the name of the devices has changed to Nordic_Buttonless, as expected:

I hope this will make things clearer, and sorry for the late reply.

Best regards.

Andreas

Replace S132 with S112

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