What‘s the problem 

When I make the nRF51‘s DFU project appear "no uECC.h" error:

And then find that: The uECC library is an external library that is not a part of the SDK and it must be installed by the user. 

Installing micro-ecc

micro-ecc is an open source library that is required to use the cryptography library. When using micro-ecc, you must ensure compliance with the license of the library as stated in the LICENSE.txt file that is included in micro-ecc.

The cryptography library expects to find the compiled micro-ecc library in InstallFolder\external\micro-ecc\micro-ecc.

To install micro-ecc, complete the following steps:

1. Install version 4.9-2015-q3-update of the GCC compiler toolchain for ARM. You can use ARM‘s Launchpad to find the toolchain for your operating system.
2. Make sure that make is installed (see, for example, MinGW, GNU Make, or Xcode).
3. Clone the micro-ecc GitHub repository into InstallFolder\external\micro-ecc\micro-ecc.
4. Enter the subdirectory for the SoC and the toolchain that you are using to build your application:
   • InstallFolder\external\micro-ecc\nrf51_keil\armgcc
   • InstallFolder\external\micro-ecc\nrf52_keil\armgcc
   • InstallFolder\external\micro-ecc\nrf51_iar\armgcc
   • InstallFolder\external\micro-ecc\nrf52_iar\armgcc
   • InstallFolder\external\micro-ecc\nrf51_armgcc\armgcc
   • InstallFolder\external\micro-ecc\nrf52_armgcc\armgcc
5. Run make to compile the micro-ecc library.

btfz@btfz-pc:~/Documents/nRF5_SDK_12.2.0_f012efa$ cd external/micro-ecc/btfz@btfz-pc:~/Documents/nRF5_SDK_12.2.0_f012efa/external/micro-ecc$ git clone https://github.com/kmackay/micro-eccbtfz@btfz-pc:~/Documents/nRF5_SDK_12.2.0_f012efa/external/micro-ecc/nrf51_armgcc/armgcc$ makemkdir _buildCompiling file: uECC.cCreating library: ../../nrf51_armgcc/armgcc/micro_ecc_lib_nrf51.a/usr/bin/arm-none-eabi-ar: creating ../../nrf51_armgcc/armgcc/micro_ecc_lib_nrf51.aDone

Another Problem

Now again make the DFU project will no this error,but show another error(we will talk about it in next blog):

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[异常解决] Make nRF51 DFU Project Appear "fatal error: uECC.h: No such file or directory"