issue #73 highlighted an issue whereby the destruction of an instance
registered as an idle or system component, would result in a hardfault.
This was due to not deregistering idle or system callbacks.
This patch has been applied to all components currently in use by the
idle or system callbacks.
An e-compass solution requires knowwlede two pieces of data to provide an
accurate heading:
- Accurate calibration of the magnetometer hardware so that reliable
measurements can be taken.
- Knowledge of the pitch and roll of of device, so that the correct
components of the X/Y and Z axis sensors of the magnetomer can be used
to sense the magnetic field in a horizontal plane regardless of the tilt
of the device.
This commit represent changes to the MicroBitAccelerometer and MicroBitCompass
classes to implemen tthese goals. More specifically, this commit provides:
- The introduciton of an interactive calibration 'game', that can rapidly
gather all the data required to calibrate the compass.
- An improved calibration algorithm based on a Least Mean Squares approach of
compass samples, as documened in Freescale Application Note AN4248.
- The inclusion of a simple Matrix4 class to enable efficient Least Mean
Squares implementation.
- A change from asynchronous to synchronous calibration of the compass when
first used. This is in repsonse to a feature request for this from users
and high level languages using microbit-dal.
- Support for detemrining tilt and roll angle in MicroBitAccelerometer
- Support for multiple co-ordinate spaces in MicroBitAccelerometer and
MicroBitCompass. Data can now be read in either RAW (unaltered) data.
MICORBIT_SIMPLE_CARTESIAN (as used previously) or NORTH_EAST_DOWN
(the industry convention in mobile phones, tablets and aviation)
- Implementation of a tilt compensated algorithm, used when determining
device heading.
Freefall now detected when the net force on the device drops below 0.4g,
rather than 0.2g as previously defined. This improves sensitivity, without
generating false positives under common use.
Also correction of minor typos / layout errors.
- updated acceleration threshold event names to reflect numeric values e.g.
GESTURE_3G, GESTURE_6G, GESTURE_8G.
- Add scoping to elements of SimpleGesture enum.
- Code scrub of code layout caused by editor with incorrect configuration.
- rename of internal state variables and functions to better reflect use.
- added clarification to some comments.
The following postures of the device are now detected:
- TILT_UP
- TILT_DOWN
- TILT_LEFT
- TILT_RIGHT
- FACE_UP
- FACE_DOWN
In addition, the following gestures are inferred:
- NONE
- SHAKE
- FREEFALL
- WHEEE (>=3g)
- SICK (>=5g)
- UNCONSCIOUS (>=8g)
Events are now triggered on the MessageBus upon the transition from one posture/gesture to another,
and a synchronous getGesture() method is now also provided to interogate the last gesture recognised.
I should be noted that the default accelerator range of +/-2g will be insufficient to detect some of
the events noted above, and MicroBitAccelerometer::setRange() should be used to increase the range
if required.
NOP/clamping behaviour out of teh micro:bit runtime and into the glue layers of higher level
languages.
- Updates to many functions to provide explicut return codes.
- Updates to many functions to remove heuristic calidation (NOP/clamping/defaults)
- Updates to ErrorNo.h to provide clearer return values, and place return values in a better scope
- Updates to MicroBitDisplay to use enums where appropriate.
MessageBus handlers can now have one of four concurrency modes for the eventuality
of an event being raised whilst a previous event is still being processed. An additional
(optional) parameter is provided to the listen() functions to allow this to be selected
on a per event handler basis. The permissable options are:
MESSAGE_BUS_LISTENER_REENTRANT:
The event handler is fired with the new event, regardless of whether or not
a previous event is still be processed by that handler.
MESSAGE_BUS_LISTENER_QUEUE_IF_BUSY:
The new event is queued until such a time as the previous event has completed
execution. The new event is then processed. This option does not preclude the
processing of the new event by other event handlers.
MESSAGE_BUS_LISTENER_DROP_IF_BUSY:
The new event is dropped, and will never be processed the the event handler.
This option does not preclude the processing of the new event by other event handlers.
MESSAGE_BUS_LISTENER_NONBLOCKING:
The event handler is self-declaring that it never blocks. This flag is used purely
for optimisation, as it permits direct execution of the event hadnelr without inducing
any overhead from the scheduler.
In addition, the following minor revisions were made in this release:
* Cleanup of the #include dependencies contained in the microbit-dal .h files
* Bugfix to the scheduler block on event matching code.
* Introduced a MICROBIT_ID_ALERT MessageBus channel, for general purpose eventing using nonces.
MicroBitAccelerometer now contans methods to allow dynamic selection of sample range
(from +/-2g to +/-8g) and sample frequency (up to 800Hz). The default settings and behaviour
remain consistent.
This is the first commit of the microbit-dal on GitHub.
This repository contains the runtime, which is a light
weight operating system developed by Lancaster University.
