nRF51-DK + GMA303 example code

Requirements

• 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

I2C Connections

• Use I2C0
  • SCL: P0.07
  • SDA: P0.30
• I2C 7-bit slave address: 0x18

Makefile

• 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 all to build and flash the program

• Exectute make help for available targets

Default gma303_initialization function in gma303.c

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.

Usage of AutoNil

• 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_NUM macro in the gSensor_autoNil.h for the moving averae order for the offset estimation. Defautl is 32.