Whilst Android devices permit explicit initiation of the BLE pairing process,
IOS based devices are only capable of implicit initiation of pairing based
on accessing a protected characteristic. Adding read capability to the
ControlPoint characteristic provides a safe and convenient way for IOS devices
to initiate pairing.
Minor amends:
- bleDisconnectionCallback signature change
- bleSetAdvertisingInterval now takes milliseconds as a parameter
- event based invocation of DFU bootloader
More specifically:
- BLUEZONE mode renamed to PairingMode (by popular request).
- Added timeout of 90 seconds before automatic device reboot.
- Move from a scroll to a print based algorithm to improve the amount of time key is displayed fully.
- Added compulsory 'click to bond' button press.
- Improved response time of tick/cross being displayed.
Changes to default BLE name. During normal operation, all micro:bits now have the same name: BBC micro:bit
When pairing mode (AKA BLUEZONE) is entered, device name details re appended as before, to give BBC micro:bit [<name>]
This is to provide a degree of anonymity to users, to make tracking of kids more difficult.
This option is now configured when the BLE stack is initialised. This ensures that SoftDevice is never
starved of CPU during periods of criticality. This does lock out the CPU for application use, but prevents
MIC failures caused by __disable_irq() operations (as found in the mbed Ticker API for example).
Minor amends:
- bleDisconnectionCallback signature change
- bleSetAdvertisingInterval now takes milliseconds as a parameter
- event based invocation of DFU bootloader
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.
- LFSR generated values in a subset of the range requested (rounded to the nearest lower power of 2).
Corrected by increasing the number of bits usedby one, such that it now generated st least the power of 2 greater.
- replaced enable/disable of interrupts with a local snapshot of randomValue. Much of the nordic software is sensitive to interrupt timings,
so best avoided where possible. Chance of race condition is low, and effect is minimal (duplicate number returned).
- Removed flashcode base authorization
- silenced unused parameter in MicroBitHeapAllocator
- bugfixed BLUEZONE mode so that sensor data is still available via BLE
The serial baud rate is set duing construction of the uBit object. We
don't need to do it again, and especially with fixed values that can't
be overridden.
Uisng libc's implementation is likely to be safer than rolling our own. At least
the failure modes are well documented. (glibc's implementation of rand() is
actually not bad).
The LFSR used only provides 1 bit of random data each time it is cycled.
This implementation generates the minimum number of bits needed. Further
it discards numbers that are bigger than required and re-calculates -
this keeps the distribution flat.
If BLE is connected when performing a hard reset, attempt to disconnect
first to allow the remote peer to handle the disconnect gracefully
without haing to wait for a supervision timeout.
- refactored BLE funcitonality into BLEManager class.
- added security requirements standard BLE profile services.
- updated bluezone pairing process to use BLE passkey exchange.
Also recalibrated loop timers in MicroBitDisplay::Error(), as used by panic()...
strange these now seem off by several orders of magnitude.
TODO: Ensure CPU is running at correct internal frequency with an oscilloscope test...
Whilst a little more invasive change than the previous warnings
supression this is more correct and more obvious as to what's being done,
and what warnigns will remain in place for the rest of the comilation
unit.
Unfortunately we can't turn it off just while nrf_soc.h is being included
as the way the defines are used the compiler can't tell the parameters
are unused until the end of the compilation unit. So we can't use the
more normal
as that pops the supression too early.
WARNING: including nrf_soc.h will turn off unused-function warnings for
the rest of the compilation unit - see included nrf_svc.h
- Enures an event listener is not deleted whilst a fiber is activiely processing a queue
- Added support for resurrection of event listeners in cases where identical listeners are removed/added repetitively.
- Add maximum depth for event queues, to prevent buggy scripts causing total memory exhaustion.
- Suppress generation of A/B click events when A+B click is generated
- preservation of event ordering on messagebus for resursive event generation cases.
- bugfix of message bus processing to prevent occasional dual processing of events
- bugfix MicroBitDisplay to behave correctly when delay parameter is zero.
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.
Minor changes to BLE profile services (cleanup prior to merge with master branch):
- Added temperature period characteristic to match design pattern of other sensors.
- Updated endinaness of MicroBitLEDService Matrix to be more intuitive.
- Cleaned up Microbit.cpp by removing unused reference to BLE services.
- Exposed serial number and naming information thr BLE DeviceInformation and API.
- Updated BLE advertisement period to be alightly more repsonsive (200ms vs 1000ms).
- BUGFIX: micro:bit name is now always generated, regardless of BLE services.
- BUGFIX: Scroll Period data length.
Updates to change the behaviour of the scroll/print/animate faily of function away
from being pre-emtive and instead prroviding queing behaviour.
Minor updates to provide complete sets of async equivalent operations
Updates to the scheduler to provide wait/notify/waitone semantics.
All message bus listeners with the micro:bit runtie are non blocking, and safe to be called
in an interrupt context. As such, these have now all been declared MESSAGE_BUS_LISTENER_IMMEDIATE
which should mitigate all unbounded event queueing effects.
Updates to BLE interface to match specification following testing by Bluetooth SIG.
Accelerometer Period: now supports READ and WRITE
Magnetometer Period: now supports READ and WRITE
LED Matrix State: now supports READ and WRITE.
UUIDs of Temperature Service characteristic corrected.
More specifically, the build system now uses the semantic versioning meta-data
held in module.json to define a major.minor.patch version. Additionally, is the branch
being compiled is *not* the master branch, the version is appended with <branchname><githash>.
Specific updates:
- Updates to CMake files to expose this to the micro:bit runtime code.
- Addition of uBit.systemVersion() to expose this to application code.
- Displaying of version string over serial if MICROBIT_DBG is enabled.
- Distribution of version string over BLE via the firmware revision characteristic.
First functionally complete BLE profile, matching BLE speicfication v1.6.
More specifically, the following services are now functional:
- AccelerometerService
- MeganetometerService
- EventService
- TemperatureServide
- IOPinService
- DFUService
- ButtonService
- LEDService
Also, updates to underlying device drivers to enable greater configurability:
- MicroBitCompass now supports variable sample rates and temperature sensing
- MicroBitAccelerometer now supports variable sample rates and ranges
- MicroBitThermometer introduced
- MicroBitMessageBus adapted to permit enumeration and block removal of listeners
Finally, MicroBit DFU Service has been changed to the new UUIDs specificed in v1.6 of BLE spec.
Previous to this patch an explicit constructor was provided for creating
MatrixPoint instances, which meant that such objects could not be put in
ROM (since they needed to be constructed at runtime).
By using the defualt construction method for structs the MatrixPoint map
is now compiled into the rodata section, hence freeing up RAM.
Saves: 4 bytes data, 56 bytes bss, 148 bytes code.
- renamed fiber flag to be more general.
- renamed idle to idleFiber to be consistent with the rest of the code.
- factored content of idle() into a funciton to avoid dupication.
- added test case to MessageBus::process() to avoid forking fibers if not requested.
- removed fiber_allow_run_idle_within mutator in favour of exposing currentFiber, as a more general solution.
If there is only 1 main fiber (plus the idle fiber) then enabling this
new feature for the main fiber (using fiber_allow_run_idle_within())
will mean that no heap is needed to swap the stack out.
Added new URGENT listener type, that ensures immediate, non queuing delivery of events.
Introduced two-pass algorithm into message bus. Only events with an event listener are now
queued at ingress - this reduces unecessary memory usage for 'uninteresting' events.
Hotfix of a minor bug in the MicroBitDFU Service that prevented BLE notifications
from being sent on the FlashCode characterisitic. Needed as the Samsung companion
app is dependent on this functionality to enable BLE programmming of the micro:bit.
Events in the micro:bit runtime are normally launched through making an instance
of the MicroBitEvent class. This update added configuration support to all the
code creating the MicroBitEvent decide if the newly created event should then be
automatically queued on the MessageBus or processed immediately by event handlers.
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.
A header file containing custom configuration options for the microbit:runtime can
now be defined through a yotaa configuration option.
For example, including the following inside a top level config.json file
will load configuration options from a file called "MicroBitCustomConfig.h" that is stored
alongside an application's main.cpp. Any options defined there will override the defaults
defined in microbit-dal/inc/MicroBitConfig.h :
{
"microbit" :{
"configfile" : "source/MicroBitCustomConfig.h"
}
}
All options defined in MicroBitConfig are now set IFF they already do not have a value.
This allows external configuration of these options much more cleanly. Additional macros
also defined to provide clean implementation for boolean configuration switches.
Also some minor bugfixes:
- Correction of typo of "Microbit.h" => "MicroBit.h"
- Fixed heap corruption bug on gcc as a result of a debug printf in an unsafe context.
This release contains a widespread set of updates and optimisations to the micro:bit
runtime, with a view to reducing the SRAM footprint of the whole system. This is to
provide as much usable HEAP storage for application programs as possible.
Specific updates and optimisations include:
- Additional compilation flags to allow the core micro:bit runtime to be configured.
These are defined in MicroBitConfig.h
- A custom heap allocator. This is now included for two reasons:
1) To provide a simple mechanism to to utilise both the mbed heap space and other memory
regions (such as unused memory in the SoftDevice region) as a single virtual heap.
2) To address some issues that have been noted that are attributable to heap fragmentation.
The micro:bit heap allocator has a simple algorithm, but one that is chosen to respond
well to the relativelt high 'heap churn' found in the micro:bit environment.
All micro:bit components and user programs now use this heap allocator trasparently.
- Updates to BLE services to remove persistent references to their GATT services. This consumes
vast amounts SRAM, rather unecessarily. Instead only handles to the relevant GATT characteristics
are now stored. This specifically includes:
+ MicroBitDFUService
+ MicroBitEventService
+ DeviceInformationService
- Updates to the Fiber scheduler to save SRAM. More specifically:
+ Removed the need to hold an empty processor context to intialise fibers.
+ The IDLE fiber now runs without a stack
+ fiber stacks are now only created when a fiber is descheduled for the first time, thereby reducing heap churn.
+ the 'main' fiber is now recycled into the fiber_pool if it leaves app_main()
+ fibers created through invoke() now only maintains the necessary part of teh parent stack that is needed, thereby
reducing the stack size of spawned fibers.
- Updates to the Message Bus to reduce the overall memory footprint of processing events. More specifically:
+ Event handlers are now always called using invoke(), such that non-blocking event handlers no longer need
a dedicated fiber to execute - thereby saving SRAM and processor time.
+ Processing of events from the event queue is now rate paced. Events only continue to be processed as long as there
are no fibers on the run queue. i.e. event processing is no longer greedy, thereby reducing the number of fibers
created on the runqueue.
- Updates to BLUEZOENE code to bring up core BLE services even if they are not enabled by default. This allows
programs that do not require BLE to operate to benefit from the full range of SRAM, whilst still allowing the
device to be programmed over BLE.
- Updates to the Soft Device initialisation configuration, reducing the size of the GATT table held in the top 1.8K
of its 8K memory region to around 800 bytes. This is sufficient to run the default set of BLE services on the micro:bit
so the additional memory is configured as HEAP storage by MicroBitHeapAllocator.
- Minor changes to a range of components to integrate with the above changes.
+ rename of free() to release() in DynamicPWM to avoid namespace collision with MicroBitHeap free()
+ rename of fork_on_block to invoke() to enhance readbility.
- Many code cleanups and updates to out of date comments.
Updates to MicroBitDisplay::setBrightness() to perform a NOP for out of bound parameters.
This aligns the functionality of the runtime with the TD simulator.
Updates the MicroBitMessageBus implementation to use fork_on_block() calls rather
than create_fiber() calls when servicing events. This provides greater optimisation
for non-blocking event handlers.
More specifically, this update:
- Replaces calls to create_fiber() ith fork_on_block during event send operations.
- Adds a queue of events, to ensure events generated from interrupt context are not serviced in interrupt context.
- Registers a listener with the idle process to empty the event queue.
The microbit fiber scheduler is often used to service event handlers by the microbit message bus.
This provides a very elegant decoupling of user code from system code, interrupt handlers and
also allows users to make blocking calls within event handlers. However, many event handlers are
non-blocking, so launching a dedicated fiber is wasteful in terms of time and SRAM.
This patch adds fork_on_block() to the scheduler. Inspired by the UNIX copy_on_write
technique, this optimisation is semantically equivalent to a create_fiber() call, but will first attempt
to execute the given function in the context of the currently running fiber, and *only* create a fiber
if the given code attempts a blocking operation.
More specifically, this update:
- adds fork_on_block() functions for parameterised and non-parameterised functions.
- adds fields to the fiber context to record the status of parent/child fibers.
- adds optimised ASM functions to store and restore Cortex M0 register context.
- adds a utility function to determine if the processor is executing in interrupt context.
- updates to sleep() and wait_for_event() to handle fork_on_block semantics.
- minor code optimsations within the scheduler.
NO_BLE can now be defined to determine whether ble
will be brought up or not at initialisation of uBit.
This is especially useful for two new Yotta targets:
bbc-microbit-classic-gcc-nosd,
bbc-microbit-classic-armcc-nosd, which do not use
softdevice.
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.
Joe Finney