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Question 1

Define runtime code/software:

Answer 1

software platform that provides an environment for executing user code - serves as an abstraction layer that developers can use to write software

Question 2

Define a microcontroller unit (MCU):

Answer 2

compact integrated circuit equipped w/ 1 or more CPUs + memory - similar to a system on a chip

Question 3

Define an embedded system:

Answer 3

electronic product comprised of one or more microcontrollers executing software instructions stored on a memory module to perform an essential function

Question 4

Which component streams data to/from the microbit and provides power?

Answer 4

micro USB

Question 5

What does a micro USB do?

Answer 5

streams data to/from the microbit and provides power

Question 6

What does the ARM Cortex-M4F processor deal with?

Answer 6

interface that handles USB connection - used for flashing code + Tx/Rx data to/from devices

Question 7

What does the ARM Cortex-M4 32-bit processor deal with?

Answer 7

user + runtime code + Bluetooth stack can run from flash memory, custom radio capabilities + integrated temp sensor

Question 8

Which processor deals with the USB connection?

Answer 8

ARM Cortex-M4F

Question 9

Which processor deals with user + runtime code?

Answer 9

ARM-Cortex-M4 32-bit

Question 10

How does the microbit communicate?

Answer 10

via BLE antenna - peripheral that talks to central devices only + also uses radio to communicate w/ other microbits!!

Question 11

What does the motion sensor include?

Answer 11

an accelerometer + magnetometer - sensor will either be LSM or FXOS

Question 12

How does the microbit connect to external components?

Answer 12

clips/plugs to the edge connector - 20 pins/strips with 5 rings

Question 13

What does the regulator do?

Answer 13

steps down voltage

Question 14

What is Xtal for?

Answer 14

electronic crystal oscillator that provides clock signal

Question 15

What buses are there in a microbit?

Answer 15

SWD, UART, I2C (external + internal)

Question 16

What does SWD do?

Answer 16

stands for serial wire debug - for programming target MCU (processor)

Question 17

What does UART do?

Answer 17

stands for universal asynchronous receiver transmitter - for exchanging data w/ device connected via USB

Question 18

What does I2C do?

Answer 18

stands for inter-integrated circuit bus - allows main component (target MCU) to communicate w/ secondary components

Question 19

Which bus deals with programming target MCU?

Answer 19

SWD

Question 20

Which bus deals with data for device connected via USB?

Answer 20

UART

Question 21

Which bus deals with communication between the target MCU and secondary components?

Answer 21

I2C

Question 22

what does the MicroBit class do?

Answer 22

consists of variables + methods that operate as drivers to control commonly used microbit features
instantiate as MicroBit uBit;
then initialise with uBit.init();

Question 23

what modes can you set uBit.display to

Answer 23

setDisplayMode(x):
-DISPLAY_MODE_BLACK_AND_WHITE = each pixel is on/off (can control brightness but for ALL) - most efficient (processing time + battery power)
- DISPLAY_MODE_BLACK_AND_WHITE_LIGHT_SENSE = same as above but display drivers also sense ambient brightness from LEDs
- DISPLAY_MODE_GREYSCALE = each pixel can independently have 256 levels of brightness

Question 24

How to intialise an MicroBitImage?

Answer 24

MicroBitImage var (“0, 255, 0, 0, 0\n…);
OR
const unint8_t var[] = {0, 1, 0, 0…); then MicroBitImage image (5, 5, var);

Question 25

How to display an image?

Answer 25

uBit.display.print(image);

Question 26

How to change pixel in image?

Answer 26

image.setPixelValue(x, y, 0/1);

Question 27

How to find value of pixel in image?

Answer 27

uBit.display.image.getPixelValue(x,y)

Question 28

What button objects are available?

Answer 28

uBit.buttonA, uBit.buttonB (MicroBitButton) + uBit.buttonAB (combined input - MicroBitMultiButton)

Question 29

How to find out if a button has been pressed?

Answer 29

.isPressed() - returns 1 if pressed and 0 if not

Question 30

What deals with asynchronous programming for microbits?

Answer 30

message bus can listen for events + call a function (event handler) when it occurs uBit.messageBus.listen(component, event, function);

Question 31

What does release_fiber() do?

Answer 31

stops the end of execution so the program will wait and listen for events even if the compiler has reached the end of the program

Question 32

What is the wildcard for events?

Answer 32

MICROBIT_EVT_ANY

Question 33

What does uBit.thermometer.getTemperature() do?

Answer 33

gets integer value representative of surface temp of application MCU (not the ambient temp!!)

Question 34

What does the log do?

Answer 34

enables a table-like format containing rows of readings/data

Question 35

What are the functions associated with log?

Answer 35

beginRow() - open file + create new row logData("column label", "value") = add data endRow() = complete logging + close file

Question 36

How to make log file visible in file explorer?

Answer 36

uBit.log.setVisibility(true);

Question 37

What is firmware?

Answer 37

midway between hardware + software permenant software that provides low-level control of device hardware

Question 38

What is the firmware for a microbit?

Answer 38

DAPLink open-source interface firmware

Question 39

What does DAPLink do?

Answer 39

- creates bridge between PC + SWD - micro:bit presents self like a USB disk - enables drag + drop programming w/o installing drivers - compatible w/ Windows, MacOS + Linux (mainly Linux) - Interface mode - hex file dropped onto USB disk is written to target MCU flash - name of USB disk = MICROBIT - Bootloader mode - hex file dropped onto USB disk is written to interface MCU flash + updates version of DAPLink - name of USB disk = MAINTENANCE

Question 40

What software does the microbit have?

Answer 40

- nRF5 Software Dev. Kit - Component Oriented Device Abstraction Layer - Porgraming Lanaguages - Python, C/C++ and MakeCode

Question 41

Microbit software: nRF5 Software Dev. Kit

Answer 41

- rich development environment for nRF52/52 sereies MCUs - provides hardware abstraction - inc. drivers, libraries, example peripherals + radio protocols

Question 42

Microbit software: Component Oriented Device Abstraction Layer

Answer 42

- micro:bit runtime software - C/C++ - abstracts hardware components as software components rep by C++ classes - offers eventing subsystem for mapping asynchronous events to event handlers

Question 43

Microbit software: Programming Languages

Answer 43

- interpreted (Python) - user code + interpreter are copied into target MCU -allow users to program micro:bit live over USB - compiled (C/C++) - user code is compiled → ARM assembly - editors (MakeCode) - high-level programming using blocks