Here are the guidelines for users to implement Secure DFU OTA(over-the-air) while using nRF52832 Solution modules. (Click on link for Raytac nRF52832 module series)
IC: nRF52832
DK: PCA10040 (for nRF52832)
SDK: 16.0.0
Softdevice: s132_nrf52_7.0.1_softdevice.hex
IDE: Keil C
PC: Win 10
Below are the guidelines to implement Secure DFU OTA by using Raytac’s nRF52832 modules, SDK16.0.0.
It consists of 2 parts:
Part 1: Bootloader & Application
Part 2: Combining and merging built files (Article link)
In this article, we will be focusing on Part 1: Bootloader & Application.
Bootloader
Path: ..\nRF5_SDK_16.0.0_98a08e2\examples\dfu\secure_bootloader\pca10040_s132_ble\arm5_no_packs
Specifically for nRF52832, programmers need to embed ECC(Elliptic Curve Cryptography) into the bootloader.
Step 1. ’micro_ecc_lib_nrf52.lib’ library can be found in the path below, but we need to boot it up first.
Step 2. Unzip ’micro-ecc-master.zip’ to the below path(create a new “micro-ecc” file first).
Step 3. Run ’gcc-arm-none-eabi-7-2018-q2-update-win32.exe’.
Step 4. Make sure the Environment variables in Win10 are set as below. (Follow the steps 1 to 6)
Step 5. Open DOS → run the “make” command under armgcc path → generate’micro_ecc_lib_nrf52.lib’
Step 6. Add ’micro_ecc_lib_nrf52.lib’ into folder: nRF_micro-ecc
Step 7. An error may occur while building bootloader without a public key:
(Shown in red frames in below screenshot)
Step 8. How to generate the public key file in Bootloader?
A. Visit DOS at path: ..\Python27\Scripts
B. Then execute:nrfutil keys generate private.pemnrfutil keys display --key pk --format code private.pem --out_file public_key.c
Step 9. Copy the pk[64] code from (public_key.c) into (dfu_public_key.c)
(Shown in red frames in below screenshot)
※Note: Make sure to save the 3 generated files:
private.pem
public_key.c
dfu_public_key.c
Step 10. Generate the bootloader file: nrf52832_xxaa_s132.hex after re-compiling the code files.
Application
Path:
..\nRF5_SDK_16.0.0_98a08e2\examples\ble_peripheral\ble_app_uart\pca10040\s132\arm5_no_packs
Before building Application code , some amendments need to be made regarding DFU-related settings and code inside Application:
Step 1. Add code in definition in C/C++ :
BL_SETTINGS_ACCESS_ONLY NRF_DFU_SVCI_ENABLED NRF_DFU_TRANSPORT_BLE=1
(Total 3 steps definitions need to be set up)
Step 2. Add the 3 paths shown below in C/C++ to make DFU work.
Step 3. Add the .c files inside red frame in (Screenshots 1 & 2)
and add the 2 groups of (nRF_DFU & nRF_SVC)(Screenshot 4) under Project(Screenshot 3)
Step 4. Add code into main.c file in Application (..\examples\ble_peripheral\ble_app_uart\main.c)
(Please refer to: main.c file at: ..\examples\ble_peripheral\ ble_app_buttonless_dfu)
Step 5.
The code of file: sdk_config.h (..\examples\ble_peripheral\ble_app_uart\pca10040\s132\config\sdk_config.h)
inside Application needs to be modified.
Step 6. Adjust the IRAM1 value in Target after implementing DFU service:
Make sure the IRAM1 Value of *p_app_ram_start is modified from default: 0x20002AD8 0xD528 to
0x20002AE8 0xD518, as shown in the red frame in the bottom right corner.
In this case, the program should run/advertise successfully.
Step 7. Create a file of: nrf52832_xxaa.hex after building application code files.
Step 8. Create a bootloader setting file of nrf52832_bootloader_secure_settings.hex via DOS.
nrfutil settings generate –family NRF52 –application nrf52832_xxaa.hex –application-version 3 —
bootloader-version 2 –bl-settings-version 1 nrf52832_bootloader_secure_settings.hex –no-backup
※Stay tuned for Part 2: Combining and merging built files in the next article, scheduled release in next week(04-Sep-2024).
Technical guidelines provided by R&D Manager: Mr. MW Lee
Edited by Sales Manager: Ms. Mandy Chao
Raytac Corporation 勁達國際電子股份有限公司
Raytac Corporation: A Bluetooth, Wi-Fi, and LoRa Module Maker based on
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