acc: 3D Accelerometer

The 3D accelerometer API supports applications for such things as collision detection, monitoring driving experience (vibration and harshness), inertial navigation, etc.

It is possible to start a logging feature which will automatically collect current acceleration with a minimum of resource requirement - thus allowing for a continuous collection of data while the device is performing other tasks. This functionality will allow implementation of a "black box" that collects various information such as G-forces, GPS positions, and CAN bus information at the time of a given incident or event.

The acceleration values are returned as mg units (SI standard: 0.001 m/s2 [meters per second squared]).

The axis of the acceleration is represented relative to the device (please see the technical manual for details).

Architecture of the Accelerometer API

The Accelerometer API is based on an asynchronous event-based model where solicited as well as unsolicited events from the accelerometer are automatically queued and delivered to the user application. The function accWaitEvent is used to return information about the various events arriving from the accelerometer. This model eliminates the requirement for the application to continuously poll for messages, and it also encourage use of multithreading with the added benefits that comes with this.

Events that are triggered by the application requesting various information from the accelerometer are therefore called solicited events, or, alternatively, they can be triggered by the accelerometer itself and are therefore instead called unsolicited events. A solicited event is, for example, when the application calls accLoggerStop and then accWaitEvent returns with event# 4. An unsolicited event works exactly the same way as a solicited event, except for the fact that accLoggerStop is no longer called by the application.

Please consult accWaitEvent for detailed information about the various events and how they are handled.

•accOpen	Opens the interface.
•accClose	Closes the interface.
•accVector	Reads an acceleration vector.
•accVectorToForce	Calculates the total force of acceleration.
•accVectorToAngles	Calculates axis angles relative to acceleration.
•accWaitEvent	Waits for an event from the acceleration interface.
•accSetAccelerationEvent	Control monitoring of acceleration.
•accAccelerationEvent	Reads acceleration event.
•accSetShockEvent	Controls monitoring of shocks.
•accShockEvent	Reads shock event.
•accLoggerSetConfig	Configures logging feature.
•accLoggerGetConfig	Reads logging configuration and status.
•accLoggerStart	Starts logging.
•accLoggerStop	Stops logging.
•accLoggerLevel	Returns the amount of buffer used by the logger.
•accLoggerRead	Reads value from logger
•accLoggerToMem	Moves the contents of the logger to memory.
•accVibrationSetWakeup	Enable or disable the ability to wake from low power modes with device vibration. See pmSuspend.