1. The BBC micro:bit and Microsoft Touch Develop
I’ll describe the technology stack we created in partnership with ARM and Lancaster University to make it simple for students to get started coding with micro:bit from a web browser, and then uncover the complexity that lies underneath in the micro:bit’s C++ runtime. The Block Editor provides an introduction to structured programming via blocks that can be snapped together. Touch Develop introduces a statically-typed scripting language with syntax-directed editor. Browser-based compilers from the Block Editor to Touch Develop and from Touch Develop to C++ automate the transition from a visual language to a text-based language, and then to C++, the language of the mbed-based micro:bit. For more information: see and 
Tom Ball, Peli de Halleux, Michał Moskal, Jonathan Protzenko
Microsoft Research

2. Globally
Emerging recognition that K-12 Computer Science is
Educationally foundational, like science, mathematics
Economically crucial, and not just for geeks
USA, Malaysia, Korea, Japan, Sweden, Canada, Germany, Hungary, Israel, Holland, Denmark, Estonia, New Zealand... it's going to happen!
England
Every child will learn computer science from primary (age 6) onwards
A crucial laboratory

3. Vision Positioning The UK journey
Educational not instrumental: Not just a vocational/economic imperative
Ideas, not technology Not even primarily about computers!
Discipline, not skill In particular, not just coding!
Computer science is a foundational subject discipline,
like maths and natural science
that every child should learn
from primary school onwards

4. Depth engagement MSR launches Computing at School (2007)
The UK journey
Depth engagement
Vibrant grass roots movement: teachers, professionals, academics.
Community of practice, to support, encourage, equip, give vision to innovative computing teachers
Independent: speaks for the subject, not for teachers, or academics, or companies, or govt.
The Big Society: works with dozens of other groups of enthusiasts: Raspberry Pi, Code Club, Codecademy, code.org, cs4fn, Apps for Good, Sonic Pi, etc
MSR launches
Computing at School (2007)
Gift economy: 3,000 resources available for free.

5. 20,000 members Growing at 500/month About 3/4 teachers
Both primary and secondary
A community
A gift economy
UK-centric, but open to international members
20,000 members
Growing at 500/month

6. 163 CAS Hubs
In-person meetings of classroom teachers, university academics, software professionals
Small, informal, welcoming, supportive

7. Started Sept 2014
in England

8. Engagement at scale Challenge The UK journey
An entirely new subject at school
3,500 secondary schools 17,000 primary schools 200,000+ teachers
Virtually no qualified teachers
Teachers hungry for support
Government explicitly standing back, inviting others to lead
Challenge

9. Vision: repeat the "BBC Micro" impact
Vision: repeat the "BBC Micro" impact. From the classroom to the kitchen table
A year-long campaign across all of BBC broadcasting
A million devices, one for each 12-year old

10. What is the BBC micro:bit?
a small personal coding device
an exciting intro to coding and making for students
an IoT “starter” kit
The BBC micro:bit is a small wearable and programmable mbed-based device that visibly features a 5x5 LED display, accelerometer, compass, buttons, I/O pins, Micro USB plug, Bluetooth Low Energy antenna, ARM Cortex-M0 processor, and battery plug. Just like Arduino, the micro:bit can be connected to and interact with sensors, displays, and other devices. The first wave of micro:bits will land in UK schools this autumn, with every Year 7 student in the UK receiving a micro:bit, for free.

11. 25 red LEDs to light up, flash messages, create games and invent digital stories
Two programmable buttons activated when pressed. Use the micro:bit as a games controller. Pause or skip songs on a playlist.
On-board motion detector or 'accelerometer' that can detect movement and tell other devices you’re on the go. Featured actions include shake, tilt and freefall. Turn the micro:bit into a spirit level. Light it up when something is moved. Use it for motion-activated games.
A built-in compass or 'magnetometer' to sense which direction you’re facing, your movement in degrees, and where you are. Includes an in-built magnet, and can sense certain types of metal. 
Bluetooth Smart Technology to connect to the internet and interact with the world around you. Connect the micro:bit to other micro:bits, devices, kits, phones, tablets, cameras and everyday objects all around. Share creations or join forces to create multi-micro:bit masterpieces. Take a selfie. Pause a DVD or control your playlist.  
Five Input and Output (I/O) rings to connect the micro:bit to devices or sensors using crocodile clips or 4mm banana plugs. Use the micro:bit to send commands to and from the rings, to power devices like robots and motors.

12. What makes the BBC micro:bit unique?
Small and attractive
low geek factor
appeals across ages, genders
Inexpensive and simple to produce/embed
wiring micro:bit to sensors, other micro:bits, …
an affordable embedded controller
Connectivity via I/O pins and Bluetooth LE
BLE to smartphones, tablets, PCs
and through these hubs, the cloud

13. Some “interesting” constraints
ARM Cortex M0
256K Flash (for program and static data)
16k RAM (for stack and heap)
Bluetooth Low Energy (BLE) stack
Support both flashing with USB and “over the air” with BLE

14. Goals for the BBC micro:bit
a browser-based programming experience
a choice of languages and programming experiences
an layered architecture that supports progression
content to support teachers in the classroom

15. Demo

16. Goals for the BBC micro:bit
a browser-based no-install experience
a choice of languages, programming experiences, platforms
an layered architecture that supports progression
content to support teachers in the classroom

17. The technology stack PL OS HDW www.touchdevelop.com
edit/run/simulate/compile
C++ micro:bit runtime
mbed platform, SDK OS
A main challenge we faced in this project was to make it simple for any student, regardless of experience, to successfully program the micro:bit. We addressed this challenge through a technical partnership with Lancaster University and ARM. Together, we provide a path from the browser-based TouchDevelop scripting environment down to safe and efficient C++, the supported language of ARM’s mbed platform.
HDW

18. a statically-typed language and libraries
Touch Develop is… 1 2
a cloud of scripts,
users
a browser-based IDE,
for mobile devices
a statically-typed language and libraries 3 4

19. Choice

20. Choice Block Editor Touch Develop Drag and drop No syntax errors
All variables are global
No types
Cursor-based editing
Few syntax errors
Global and local variables
Static types

21. Some of the micro:bit APIs
Basic
show number
show string
show animation
LED
direct manipulation of display (plot, unplot, point)
Image
creation of “sprites” and “sprite sheets”
Input
event-based and polling
buttons, accelerometer, compass
Pins
analog/digital read/write
pitch
Game
simple game
Events
for BLE

22. ARM runtime (precompiled)
USB
Web browser 1
Block Editor script
User edits script and compiles
Compile
TouchDevelop
Block Editor 1
Touch Develop script
Drive
C++ micro:bit runtime
Compile
Touch Develop
ARM 3
User copies
ARM binary
to micro:bit drive
Compile
ARM
mbed C++ SDK
C++
ARM machine code
After programming a TouchDevelop script in the browser, the user can request compilation to an ARM binary. The TouchDevelop to C++. The second compilation happens in the cloud, where the generated C++ is compiled and linked with the C++ runtime, producing an ARM binary sent back to the user.
ARM runtime (precompiled)
ARM binary
User accepts “download”
of ARM binary 2

23. Programming progression
Tile-Based
Programming
Block-Based
Simplified
Language
Lang. & IDE
Full Language & IDE
Kodu / Spark
Touch Develop
Small Basic
Visual Studio
micro:bit
Kodu
AGE PROGRESSION

24. The technology stack PL OS HDW www.touchdevelop.com
edit/run/simulate/compile
C++ micro:bit runtime
mbed platform, SDK OS
A main challenge we faced in this project was to make it simple for any student, regardless of experience, to successfully program the micro:bit. We addressed this challenge through a technical partnership with Lancaster University and ARM. Together, we provide a path from the browser-based TouchDevelop scripting environment down to safe and efficient C++, the supported language of ARM’s mbed platform.
HDW

25. ARM’s mbed platform http://developer.mbed.org/
mbed-compatible board appears as mounted drive when connected via USB
Copy hex file to drive to flash it
choice of Windows, MacOs, ChromeBooks, Linux
no installation needed
Free, web-based development environment
Compile C++ to hex file using armcc or gcc
mbed SDK is open source under Apache 2.0

26. User codes TouchDevelop script and presses “compile” button
Web browser
User codes TouchDevelop
script and presses “compile” button
TouchDevelop script 1
USB
Drive
Compiler 1
TouchDevelop
C++
C++ program
ARM binary
User copies ARM binary
to micro:bit drive 3
Compiler 2
C++
After programming a TouchDevelop script in the browser, the user can request compilation to an ARM binary. The TouchDevelop to C++. The second compilation happens in the cloud, where the generated C++ is compiled and linked with the C++ runtime, producing an ARM binary sent back to the user.
mbed C++ SDK 2
ARM
User accepts download
of ARM binary
mbed compile service
ARM binary program

27. BB micro:bit – the C++ runtime
Provides a Device Abstraction Layer (OS) for micro:bit
hardware components
simple message bus and events
co-routines (fibers) and non-preemptive scheduler
display driver
high-level helper functions (scroll string)
a few managed types (reference counted)
To be open sourced (currently private) at

28. The technology stack PL OS HDW www.touchdevelop.com
edit/run/simulate/compile
C++ micro:bit runtime
mbed platform, SDK OS
A main challenge we faced in this project was to make it simple for any student, regardless of experience, to successfully program the micro:bit. We addressed this challenge through a technical partnership with Lancaster University and ARM. Together, we provide a path from the browser-based TouchDevelop scripting environment down to safe and efficient C++, the supported language of ARM’s mbed platform.
HDW

29. Control and Coordination
MicroBitDisplay
represents the LED matrix array of the device
MicroBitButton
represents a single, generic button
MicroBitMultiButton
represents a virtual button
MicroBitCompass
represents an implementation of the Freescale MAG3110 I2C Magnetometer
MicroBit
represents the micro:bit device as a whole and its various components
MicroBitComponent
abstract representation of a hardware component
the functions needed to drive/poll that hardware
MicroBitEvent
an event generated by some MicroBitComponent
MicroBitMessageBus
delivers asynchronous MicroBitEvents via a send/listen pattern
Fiber
a lightweight representation of a cooperative thread of execution (i.e., a co-routine)

30. More Classes MicroBitSerial MicroBitIO MicroBitI2C
a subclass of mbed’s Serial that accepts micro:bit specific data types
MicroBitIO
a representation of all given I/O pins on the edge connector
MicroBitI2C
indirect access to mbed I2C
MicroBitEventService
provides a BLE gateway for sending MicroBitEvents to the MicroBitMessageBus
MicroBitDFUService represents a Device Firmware Update (DFU) loader that
provides a simple mechanism to identify an individual micro:bit amongst a classroom of others
allows BLE devices to discover and cache a passcode that can be used to flash the device over BLE
provides a BLE escape route for programs that 'brick' the micro:bit

31. BBC micro:bit content Quick Start Guide for Teachers
Distributed to 20,000+ teachers
40+ online lessons
Lesson = Activity + Quiz + Challenges
Mapped to UK CS curriculum
Printable

32. Questions?