The BBC micro:bitand

Microsoft Touch DevelopTom Ball, Peli de Halleux, Michał Moskal, Jonathan Protzenko

Microsoft Research

http://www.microbit.co.uk/

http://www.touchdevelop.com/

GloballyEmerging 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

The UK journey

Vision

Positioning

• Educational not instrumental:Not just a vocational/economic imperative

• Ideas, not technologyNot even primarily about computers!

• Discipline, not skillIn particular, not just coding!

Computer science is a foundational

subject discipline,like maths and natural

sciencethat every child should

learnfrom primary school

onwards

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 launchesComputing at

School(2007)

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

163 CAS Hubs In-person meetings of classroom teachers, university academics, software professionals

Small, informal, welcoming, supportive

Started Sept 2014

in England

The UK journey

Engagement at scale

• An entirely new subject at school• 3,500 secondary schools

17,000 primary schools200,000+ teachers

• Virtually no qualified teachers

• Teachers hungry for support

• Government explicitly standing back, inviting others to lead

Challenge

• 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

What is the BBC micro:bit?

• a small personal coding device

• an exciting intro to coding and making for students

• an IoT “starter” kit

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

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

Demowww.microbit.co.uk

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

The technology stack

• www.touchdevelop.com• edit/run/simulate/compile

• C++ micro:bit runtime

• mbed platform, SDK

OS

HDW

PL

a cloud of scripts, users

a browser-based IDE, for mobile devices

a statically-typed language and libraries

www.github.com/Microsoft/TouchDevelop

Touch Develop is…

1 2

3 4

Choice

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

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

Touch Develop script

C++ micro:bit runtime

ARM binary

Compile

ARM

mbed C++ SDK

C++

1

User copies ARM binary

to micro:bit drive

3

User edits script and compiles

Drive

Web browser

2

USB

User accepts “download” of ARM binary

CompileTouch Develop

ARM

ARM runtime (precompiled)

ARM machine code

CompileTouchDevelop

Block Editor

Block Editor script1

KoduAGE PROGRESSION

Tile-Based Programmi

ng

Block-Based

Programming

Simplified

Language

Simplified Lang. &

IDE

Full Language

& IDE

Kodu / Spark Touch Develop Small Basic Visual Studio

Programming progression

micro:bit

The technology stack

• www.touchdevelop.com• edit/run/simulate/compile

• C++ micro:bit runtime

• mbed platform, SDK

OS

HDW

PL

ARM’s mbed platform

• 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

• http://developer.mbed.org/• Free, web-based development environment• Compile C++ to hex file using armcc or gcc

• mbed SDK is open source under Apache 2.0• https://developer.mbed.org/users/mbed_official/code/mbed-src/ • https://developer.mbed.org/handbook/mbed-library-internals

TouchDevelop script

C++ program

ARM binary program

Compiler1

TouchDevelop

C++

ARM binary

Compiler2

mbed compile service

ARM

mbed C++ SDK

C++

1

User copies ARM binaryto micro:bit drive

3

User codes TouchDevelopscript and presses “compile” button

Drive

Web browser

2

USB

User accepts download of ARM binary

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 • https://github.com/lancaster-university/microbit-dal

The technology stack

• www.touchdevelop.com• edit/run/simulate/compile

• C++ micro:bit runtime

• mbed platform, SDK

OS

HDW

PL

Control and Coordination

• 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)

MicroBitDisplayrepresents the LED matrix array of the device

MicroBitButtonrepresents a single, generic button

MicroBitMultiButtonrepresents a virtual button

MicroBitCompassrepresents an implementation of the Freescale MAG3110 I2C Magnetometer

More Classes

• MicroBitSerial• 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

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

Questions?