This repository attempts to follow a basic directory tree organization,
with libraries in lib, source code in src,
The analysis subdirectory currently consists of code for preliminary data processing.
The tools directory contains the
GNU ARM Embedded Toolchain,
needed to compile C++ code for the ARM processor used in this project.
The toolcahin version is version 4.9-2015-q3,
The code running on the ARM proccessor is C++.
The heart rate calculations require the use of vectors from the C++11 standard library.
I ran into some issues here when using the MBED compiler, as I believe it uses the C++98 standard library.
My solution to this was to export the program from the online MBED compiler to the ARM toolchain. This gave me a
Makefile and all the relevant MBED libraries, such as the BLE_API, nrf51822, and mbed. All I had to do was add
the path to the ARM toolchain, and change the std compiler flag to C++11. I also added an upload function.
At the time of writing, the MBED libraries
in this repository are out of date and should be exported again.
Once the code is ready to be compiled and uploaded to the device:
make
make merge
make upload
The first two commands place the output files in a directory entitled ".build" in the current working directory. The third command copys the 'combined.hex' to the device. This file that has been merged with the softdevice from the second command.
To clean the directory after the build:
make clean
In order to read data from a serial port, connect the TX and RX pins on the BLE Nano to RX and TX on the MK20 (in that order). To program the nRF51822 on the BLE Nano, connect the DCLK and DIO pins of the BLE Nano to the DCLK and DIO pins on the MK20. DCLK DIO on the BLE Nano -> MK20 DCLK DIO
| BLE Nano Pin | MK20 Pin |
|---|---|
| TX | RX |
| RX | TX |
| DLCK | DCLK |
| DIO | DIO |
In Kiel v5, the BLE Nano device can be found under Nordic Semiconductor -> nRF51 Series -> nRF51822_xxAA. This version has 256kB flash + 16kB RAM.