ADXL362 - Microcontroller No-OS Driver

Supported Devices

ADXL362

Evaluation Boards

PmodACL2

Overview

The ADXL362 is an ultralow power, 3-axis MEMS accelerometer that consumes less than 2 μA at a 100 Hz output data rate and 270 nA when in motion triggered wake-up mode. The ADXL362 always provides 12-bit output resolution; 8-bit formatted data is also provided for more efficient single-byte transfers when a lower resolution is sufficient. Measurement ranges of ±2 g, ±4 g, and ±8 g are available, with a resolution of 1 mg/LSB on the ±2 g range. For applications where a noise level lower than the normal 550 μg/√Hz of the ADXL362 is desired, either of two lower noise modes (down to 175 μg/√Hz typical) can be selected at minimal increase in supply current. In addition to its ultralow power consumption, the ADXL362 has many features to enable true system level power reduction. It includes a deep multimode output FIFO, a built-in micropower temperature sensor, and several activity detection modes including adjustable threshold sleep and wake-up operation that can run as low as 270 nA at a 6 Hz (approximate) measurement rate. A pin output is provided to directly control an external switch when activity is detected, if desired. In addition, the ADXL362 has provisions for external control of sampling time and/or an external clock.

The goal of this project (Microcontroller No-OS) is to be able to provide reference projects for lower end processors, which can't run Linux, or aren't running a specific operating system, to help those customers using microcontrollers with ADI parts. Here you can find a generic driver which can be used as a base for any microcontroller platform and also specific drivers for Renesas platforms.

HW Platform(s):

Driver Description

The driver contains two parts:

The driver for the ADXL362 part, which may be used, without modifications, with any microcontroller.
The Communication Driver, where the specific communication functions for the desired type of processor and communication protocol have to be implemented. This driver implements the communication with the device and hides the actual details of the communication protocol to the ADI driver.

The Communication Driver has a standard interface, so the ADXL362 driver can be used exactly as it is provided.

There are three functions which are called by the ADXL362 driver:

SPI_Init() – initializes the communication peripheral.
SPI_Write() – writes data to the device.
SPI_Read() – reads data from the device.

SPI driver architecture

The following functions are implemented in this version of ADXL362 driver:

Function	Description
unsigned char ADXL362_Init(void)	Initializes the device.
void ADXL362_SetRegisterValue(unsigned short registerValue, unsigned char registerAddress, unsigned char bytesNumber)	Writes data into a register.
void ADXL362_GetRegisterValue(unsigned char *pReadData, unsigned char registerAddress, unsigned char bytesNumber)	Performs a burst read of a specified number of registers.
void ADXL362_GetFifoValue(unsigned char *pBuffer, unsigned short bytesNumber)	Reads multiple bytes from the device's FIFO buffer.
void ADXL362_SoftwareReset(void)	Resets the device via SPI communication bus.
void ADXL362_SetPowerMode(unsigned char pwrMode)	Places the device into standby/measure mode.
void ADXL362_SetRange(unsigned char gRange)	Selects the measurement range.
void ADXL362_SetOutputRate(unsigned char outRate)	Selects the Output Data Rate of the device.
void ADXL362_GetXyz(short x, short y, short *z)	Reads the 3-axis raw data from the accelerometer.
float ADXL362_ReadTemperature(void)	Reads the temperature of the device.
void ADXL362_FifoSetup(unsigned char mode, unsigned short waterMarkLvl, unsigned char enTempRead)	Configures the FIFO feature.
void ADXL362_SetupActivityDetection(unsigned char refOrAbs, unsigned short threshold, unsigned char time)	Configures activity detection.
void ADXL362_SetupInactivityDetection(unsigned char refOrAbs, unsigned short threshold, unsigned short time)	Configures inactivity detection.

Downloads

Renesas RL78G13 Quick Start Guide

This section contains a description of the steps required to run the ADXL362 demonstration project on a Renesas RL78G13 platform using the PmodACL2.

Required Hardware

Renesas Demo Kit for RL78G13 (Renesas)
PmodACL2

Required Software

IAR Embedded Workbench for Renesas RL78 Kickstart

Hardware Setup

A PmodACL2 has to be connected to the PMOD1 connector.

Reference Project Overview

The reference project continuously displays on the LCD the accelerations on x-axis, y-axis and x-axis and simultaneously detects any activity or inactivity detected by the device.

Software Project Tutorial

This section presents the steps for developing a software application that will run on the Renesas Demo Kit for RL78G13 for controlling and monitoring the operation of the ADI part.

Run the IAR Embedded Workbench for Renesas RL78 integrated development environment.
Choose to create a new project (Project – Create New Project).
Select the RL78 tool chain, the Empty project template and click OK.

Select a location and a name for the project (ADIEvalBoard for example) and click Save.

Open the project’s options window (Project – Options).
From the Target tab of the General Options category select the RL78 – R5F100LE device.

From the Setup tab of the Debugger category select the TK driver and click OK.

Extract the files from the lab .zip archive and copy them into the project’s folder.

The new source files have to be included into the project. Open the Add Files… window (Project – Add Files…), select all the copied files and click open.

At this moment, all the files are included into the project.
The project is ready to be compiled and downloaded on the board. Press the F7 key to compile it. Press CTRL + D to download and debug the project.
A window will appear asking to configure the emulator. Keep the default settings and press OK.

To run the project press F5.

03 Sep 2012 13:02 · Dragos Bogdan