- nRF51-DK
- nRF51 SDK: tested with Version 10.0.0
- GCC ARM embedded compiler: tested with gcc-arm-none-eabi-4_9-2015q1-20150306
- GMA303
- Use I2C0
- SCL: P0.07
- SDA: P0.30
- I2C 7-bit slave address: 0x18
- Modify the location of the SDK to your actual directory
#
# The base directory for nRF51 SDK
#
nRF51_SDK_ROOT := /C/Data/nRF51_SDK/V10_0_0
- Modify the location of the GNU tools to your actual directory
GNU_INSTALL_ROOT := C:/Program Files (x86)/GNU Tools ARM Embedded/4.9 2015q1
-
Execute
make allto build and flash the program -
Exectute
make helpfor available targets
Default initialization steps:
- Turn on offset temperature compensation
- Set to continuous mode
- Turn on low pass filter
- Set data ready INT, ative high, push-pull
You may change the behavior of this initialization function to suit your purpose. Please refer to datasheet for more details on the register settings.
- The program will do an offset AutoNil when executed. Hold the g-sensor steady and maintain in level, then press 'y' after the program prompt for input.
- You may change the
DATA_AVE_NUMmacro in the gSensor_autoNil.h for the moving averae order for the offset estimation. Defautl is 32.
- The pedometer demo library is adapted from MEMS & Sensor Industry Group open source project.
- Algorithm in brief:
- The acceleration feeded to the algorithm should be reported in g
- Increase step counts (walkStruct.HLI) when max of the X/Y/Z datas increasingly cross the LI thershold (walkStruct.LIthrW or walkStruct.LIthrA).
- It will search for the peak when the cross occurs.
- The time between peaks is checked againt walkStruct.timeThr (default 250ms). If the time is too short, then the counted step will be rewinded.
- It will classify the peak by the HI threshold (walkStruct.HIthW or walkStruct.HIthA). It will store the counts to walkStruct.HIt/HIcnt when it is larger than HI, and to walkStruct.LIt/LIcnt if otherwise.