Commit graph

188 commits

Author SHA1 Message Date
James Devine 68474c5e58 microbit: modified constructor for DynamicPwm
Previously there would be the possibility of the period being reset
each time a new DynamicPwm was instantiated. This has now been
removed from the constructor, and the comments have been updated
2016-01-12 20:50:42 +00:00
James Devine 6b1e020392 microbit: formatting corrections
There was some incorrect tabulation in a few lines of this file, this has now been corrected.
2016-01-12 20:50:42 +00:00
James Devine c04de3f93c Merge pull request #47 from remay/serial-baud
Remove unnecessary uBit.serial.baud() calls
2016-01-11 14:03:40 +00:00
Joe Finney 32961973bb microbit: Updates to MicroBitAccelerometer to use sample data accessor methods throughout.
All internal uses of accelerometer sample values now updated to access the
data via accessor methods. This now ensures consistent use irrespective of
the coordinate system used.
2016-01-09 19:32:30 +00:00
Joe Finney 0da7903e24 Merge branch 'master' into compass-autocalibration 2016-01-09 19:10:04 +00:00
Joe Finney db25d4c0c3 microbit: Further corrections to comment blocks 2016-01-09 18:47:15 +00:00
Joe Finney 0e7a6979da microbit: Comment Cleanup
corrections to comment blocks only.
2016-01-09 11:54:23 +00:00
Joe Finney 6916d506b8 microbit: Removed print funcitons from matrix class due to SRAM overhead of
native printf() call.

The Matrix4::print() function is useful, but non essential for most
applications, and the underlying printf() call required cost an
additional 1K of RAM on first use, which is currently above the budget for
micro:bit.
2016-01-09 10:25:26 +00:00
Joe Finney d51b1205f7 microbit: Added support for compass tilt compensation
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.
2016-01-09 00:20:19 +00:00
Joe Finney 3416e54a36 microbit: increase sensitivity of freefall detection
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.
2016-01-05 16:23:47 +00:00
Joe Finney 17632adafa Merge branch 'master' into basic-gestures 2016-01-05 15:50:53 +00:00
Joe Finney d3587d888c microbit: code scrub of MicroBitAccelerometer gesture recognition code
- 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.
2016-01-05 15:44:57 +00:00
Joe Finney 55601f3e0e Merge branch 'master' into secure-ble 2016-01-05 01:25:52 +00:00
Joe Finney 6763a9ba6c Merge branch 'ble-disconnect-on-reset' of https://github.com/remay/microbit-dal into remay-ble-disconnect-on-reset 2016-01-05 00:13:26 +00:00
Joe Finney e1f75b2c4c microbit: Added read capability to MicroBitDFUService::ControlPoint characteristic
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.
2016-01-04 23:41:22 +00:00
Joe Finney 7a71b58bd4 microbit: Revert explicit use of public addresses in pairing mode 2016-01-04 23:06:48 +00:00
Joe Finney 203246b975 WIP: Revert to public addresses pending further debug 2015-12-18 12:27:08 +00:00
Joe Finney c7ea0af6fe WIP: Analysing correct use of private resolvable addresses 2015-12-17 14:27:57 +00:00
Joe Finney 14831ac9b9 Updates to BLE 2.1.11 / ble-nrf51822 2.2.3
Minor amends:
  - bleDisconnectionCallback signature change
  - bleSetAdvertisingInterval now takes milliseconds as a parameter
  - event based invocation of DFU bootloader
2015-12-11 04:57:06 +00:00
Joe Finney 6d610f049a microbit: Updates to Pairing Mode to improve the user experience
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.
2015-12-11 03:43:18 +00:00
Joe Finney 5a9f5d42bd microbit: Updates to enable anonymous advertising during normal operation
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.
2015-12-11 02:09:31 +00:00
Joe Finney e042a55522 microbit: Added compile time option to enabe support for BLE private resolvable addresses.
Introduced MICROBIT_BLE_PRIVATE_ADDRESSES configuration option.
Disabled by default, as it did not resolve binds correctly on Android 4.4.2
2015-12-11 01:38:22 +00:00
Joe Finney 6f5ad99aa2 BUGFIX: Enabled BLE_COMMON_OPT_RADIO_CPU_MUTEX option
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).
2015-12-11 01:16:48 +00:00
Joe Finney b6ca1365f7 microbit: Added explicit BLE disconnection requests on DFU and soft reset 2015-12-11 00:55:33 +00:00
Joe Finney 1e5d5c8dcf Updates to BLE 2.1.11 / ble-nrf51822 2.2.3
Minor amends:
  - bleDisconnectionCallback signature change
  - bleSetAdvertisingInterval now takes milliseconds as a parameter
  - event based invocation of DFU bootloader
2015-12-11 00:24:21 +00:00
Joe Finney 1b18ac8641 microbit: Added basic gesture recognition into MicroBitAccelerometer
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.
2015-12-03 15:11:31 +00:00
Joe Finney f5cf8f2dd4 microbit: Minor optimisations to patch
- 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).
2015-11-30 00:43:24 +00:00
Joe Finney 958136673f Merge branch 'fix-random' of https://github.com/remay/microbit-dal into remay-fix-random 2015-11-29 23:43:46 +00:00
Joe Finney ae93079a65 code cleanup 2015-11-25 21:21:04 +00:00
Joe Finney 6d1004fb28 Updates to DFU service to align with BLE standard BLE security
- Removed flashcode base authorization
- silenced unused parameter in MicroBitHeapAllocator
- bugfixed BLUEZONE mode so that sensor data is still available via BLE
2015-11-20 11:32:42 +00:00
Robert May 051575d911 Tidy up gcc -Wall fixes. 2015-11-18 23:13:57 +00:00
Robert May de681e68c3 Add diagnostic message to yotta/cmake output to remind us that we have silenced warnings. 2015-11-18 23:04:59 +00:00
Robert May 6c330079b1 Remove unnecessary uBit.serial.baud() calls
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.
2015-11-18 22:50:19 +00:00
Robert May 5333729644 Revert "Cchange random() to use libc srand()/rand()"
This reverts commit db5227872a.

return to using our own random implementation.
2015-11-18 15:50:44 +00:00
Robert May db5227872a Cchange random() to use libc srand()/rand()
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).
2015-11-18 14:15:17 +00:00
Robert May 1bb4377c8c Combine loops and fix max returned value. 2015-11-18 12:08:34 +00:00
Michal Moskal 845bf4838c Fix allocation size for ImageData (the header is 6, not 4 bytes long) 2015-11-17 15:57:19 -08:00
Robert May 901faaeec7 reset variable m in the correct place. 2015-11-17 18:51:10 +00:00
Robert May 892689c54a Fix Microbit::random() to be random
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.
2015-11-17 18:33:34 +00:00
Joe Finney b44095f0c5 BUGFIX: String comparison operations
Corrected response of < and > operations where substrings are compared.
2015-11-17 17:20:30 +00:00
Joe Finney 9b5fa0fcfc minor bugfixes in MICROBIT_HEAP_DEBUG 2015-11-17 16:58:42 +00:00
Robert May 51ea69201e Disconnect BLE before hard reset
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.
2015-11-17 13:12:27 +00:00
Joe Finney ac381fa5dc microbit: Alpha version of standard BLE MITM passkey security
- refactored BLE funcitonality into BLEManager class.
- added security requirements standard BLE profile services.
- updated bluezone pairing process to use BLE passkey exchange.
2015-11-16 13:44:27 +00:00
Joe Finney 79c739674c first compiling build. 2015-11-15 14:31:44 +00:00
Joe Finney 6dca3ed8d4 microbit: pre-compilation backup only. 2015-11-13 20:38:37 +00:00
Michal Moskal 56a560e5bc Merge branch 'master' into flatstring
Conflicts:
	.gitignore
	inc/ErrorNo.h
	source/MicroBitDisplay.cpp
	source/MicroBitImage.cpp
2015-11-12 16:13:45 -08:00
Joe Finney ea51f396ca Added compatibility for builds under ARMCC 2015-11-08 18:04:17 +00:00
Joe Finney 435debffed Merge branch 'quiet-gcc-build' of https://github.com/remay/microbit-dal into remay-quiet-gcc-build 2015-11-08 13:50:33 +00:00
Joe Finney 13456c60c1 microbit: Removal of explicit Serial instance for debugging.
Debugging now runs via the standrad MicroBit::serial interface.
2015-11-01 23:42:53 +00:00
Joe Finney 1a65e4e7bc microbit: Added support for soft reset button in panic mode
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...
2015-11-01 21:33:46 +00:00
Robert May b8083908a7 Correct warnings supression in more obvious way
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.
2015-11-01 20:19:18 +00:00
Robert May 9591ef40dc Turn off -Wunused-parameter for include "nrf_soc.h"
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
2015-11-01 20:19:17 +00:00
Robert May 1a1a5976a8 Silence GCC -Wall 2015-11-01 20:19:17 +00:00
Robert May 3a8c72144f up the cmake version required to 2.8.12, which is required for target_compile_options. 2015-11-01 20:19:17 +00:00
Robert May a39ba7d4f7 Turn off GCC warnings when building the dependancies 2015-11-01 20:19:17 +00:00
Robert May b2d3417559 Fix build when $git_branch fails to be set correctly. 2015-11-01 20:19:17 +00:00
Joe Finney 194f19a428 Merge branch 'simplified-eventing' 2015-11-01 18:22:27 +00:00
Joe Finney 1b6d6038c1 Merge branch 'master' into tight-validation 2015-11-01 16:28:08 +00:00
Joe Finney 77af825df0 Merge branch 'master' into simplified-eventing 2015-11-01 16:27:15 +00:00
Joe Finney 39abf824dc microbit: More efficient handling of events
Removed unnecessary queing of item on the MessageBus, whilst maintaining causal ordering.
2015-11-01 15:16:27 +00:00
Joe Finney b2e9369771 microbit: BUGFIX DoS attacks on the MessageBus
- 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.
2015-11-01 12:59:52 +00:00
Joe Finney 84da6a4a09 microbit: Minor bug fixes and refinements
- 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.
2015-10-31 10:27:38 +00:00
Joe Finney 0fa8296048 microbit: BUGFIX safe deletion of listeners
also correction to minor bu in MicroBitFiber that could conceivably send more
notifications that it should...
2015-10-29 00:08:33 +00:00
Joe Finney 1eeaeca2c6 microbit: BUGFIX - correct initialization of MicroBitListener
code now correctly initiailizes the evt_queue filed needed to prevent
lockup during event processing (understandably!).
2015-10-28 14:17:12 +00:00
Michal Moskal 3900962556 Remove specific panic codes for ref-counting. 2015-10-27 08:28:06 -07:00
Michal Moskal 59853855b0 Remove caching of getSerial(); use temporary for BLE init 2015-10-27 08:26:07 -07:00
Michal Moskal 6437e714fa Delete when ref-count goes to 1, not 2\! 2015-10-27 08:19:56 -07:00
Michal Moskal c1050df0d9 Make the image width/height 16 bit wide 2015-10-27 08:02:42 -07:00
Joe Finney 7f64a4c703 microbit: BUGFIX Corrected incorrect handling of MicroBitMessageBus::add return values. 2015-10-26 16:37:12 +00:00
Joe Finney 823a956d68 microbit: First cut at updates to provide tight validation within the runtime code, with a view to moving
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.
2015-10-25 21:51:33 +00:00
Michal Moskal 7b82f3e8eb Improve comments; cleanup 2015-10-25 13:09:24 -07:00
Michal Moskal 98ffcc1fd1 Add status panic codes for ref-count errors 2015-10-25 12:59:45 -07:00
Michal Moskal 85b4e45863 Order-of-initialization fix. 2015-10-25 11:38:00 -07:00
Michal Moskal d0b75c96d1 Add MicroBitImage::isReadOnly,clone.
Add MicroBitImage,ManagedString::leakData().
Work more on incr()/decr() protocol.
2015-10-25 10:03:14 -07:00
Michal Moskal 11c99d0b84 Make the reference count always odd to make it possible to distinguish it from a vtable 2015-10-25 08:30:05 -07:00
Michal Moskal 5df59c2f7e Remove VirtualRefCounted class; non-virtual <-> virtual casts are not no-ops. 2015-10-24 21:52:51 -07:00
Michal Moskal 4f82a6c37c Use RefCounted also for MicroBitImage. 2015-10-24 20:58:03 -07:00
Michal Moskal 9330b401d5 Move RefCounted class to a separate file 2015-10-24 20:30:15 -07:00
Michal Moskal 5a10bda561 First stab at more memory efficient strings 2015-10-24 19:34:04 -07:00
Michal Moskal 057158c9f3 Cache getSerial(); otherwise BLE information device initalization may crash 2015-10-24 19:28:36 -07:00
Joe Finney bfe1b4db53 microbit: some work on tightening the API return codes.
still work in progress.
2015-10-21 11:35:59 +01:00
Joe Finney 613f524bab microbit: BUGFIX: micro:bit not entering BLUEZONE mode cleanly
Fixed bug in GAP advertisement configuration.
2015-10-19 14:42:13 +01:00
Joe Finney 72e5a9a6a6 microbit: BUGFIX - post merge fixes
- MicroBitDisplay::scroll() timing bug
  - MicroBitDisplay::print() timing bug
  - MicroBitFiber wait/notify bug
2015-10-18 19:09:54 +01:00
Joe Finney 424b825185 Merge branch 'master' into simplified-eventing
Conflicts:
	inc/MicroBitMessageBus.h
2015-10-18 18:20:03 +01:00
Joe Finney 80f79f7faf Merge branch 'master' into ble-profile
Conflicts:
	source/CMakeLists.txt
	source/MicroBit.cpp
	source/MicroBitFiber.cpp
	source/MicroBitMessageBus.cpp
	source/MicroBitSuperMain.cpp
2015-10-18 17:54:37 +01:00
Joe Finney db3eccf6ff microbit: Final updates to BLE profile
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.
2015-10-18 14:46:42 +01:00
Joe Finney aca544677e microbit: Updates to enable queing of display animation calls
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.
2015-10-17 20:35:16 +01:00
Joe Finney 068822ff12 Merge branch 'matrix-point-optimisation' of https://github.com/dpgeorge/microbit-dal into dpgeorge-matrix-point-optimisation 2015-10-14 09:38:13 +01:00
Joe Finney 2011886e64 microbot: Cleanup of #ifdef in MicroBitHeapAllocator
Removed compiler warning if MICROBIT_HEAP_REUSE_SD is not defined.
2015-10-09 16:58:10 +01:00
Joe Finney 6764c732ea microbit: BUGFIX to MicroBtDFU Service
- Updates to UI handling to avoid starving out the processor.
  - Clears screen before entering DFU bootloader
2015-10-09 01:14:36 +01:00
Joe Finney 122d885ee8 microbit: Updated Bluetooth device name from MicroBit to micro:bit to match brand guidelines 2015-10-09 00:03:01 +01:00
Joe Finney ce2cc57bf1 microbit: Optimisation of internal Message Bus listeners
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.
2015-10-08 23:49:14 +01:00
Joe Finney 1d76def8fa microbit: BLE service bugfixes
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.
2015-10-08 23:23:00 +01:00
Joe Finney 85a26dc8e1 microbit: Updates to enable semantic versioning of the micro:bit runtime DAL
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.
2015-10-08 14:37:35 +01:00
Joe Finney 2230e39340 microbit: BUGFIX: #1291 ManagedString(INT_MIN) does not work properly
Corner case error in serialization code for INT_MIN only - corrected.
2015-09-29 23:51:20 +01:00
Joe Finney 18236810a3 microbit: BLE Profile Beta 1
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.
2015-09-28 21:40:44 +01:00
Damien George 0dcb6834ec microbit: Use default constructor for MatrixPoint so data is ROMable.
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.
2015-09-25 21:19:10 +01:00
Joe Finney 4314b68643 microbit: First implementation of Temperature Service 2015-09-23 22:15:44 +01:00
Joe Finney eb5ed28f74 microbit: First cut at MicroBitButtonService and microBitIOPinService
Strictly still development - untested code.
2015-09-22 16:13:08 +01:00
Joe Finney ef613e9d86 microbit: Added BLE Magnetometer service compilation, initialization and configuration options 2015-09-19 22:19:57 +01:00