Introduction to basic programming Kai Zang Jul 2 nd, 2012

Introduction Programming: one of the tools that you can change lives around you – Want to find if a picture has been photoshoped? – Robot, mindrover – Game development? For this lecture, the grammar will be based upon C. The contents will ONLY cover our basic use for Arduino.

What’s inside a PC? Central processing unit Memory(ROM)Memory(RAM) Input device (keyboard, mouse, gamepads) Output device (head phones, monitor)

What about our Teensy??? Central processing unit Memory(ROM)Memory(RAM) Input device (sensors, buttons, knobs) Output device (head phones, monitor) What if we want to design TAIKO DRUM MASTER?!

So let’s go in further… What’s inside a memory? Bit: smallest unit, 1 bit reprensent 0 or 1 Byte = 8 bits 1kb = 1024 bytes 1Mb=1024 kb 1Gb=1024Mb A typical 6*5 memory array

How do we use bits to represent variable & constant? Variable & constant both name a place in memory where you store a Value of a certain Type. Their difference: the Value of Variable can be changed, but constant cannot. How to represent value with bits? Use binary or hexadecimal: ( ) 2 = (2c) 16 =(44) 10 For a series of n bits, we may represent 2 n number in total.

Then what about data type? Int (integer, 4 bytes) – Signed: to – Unsigned: 0 to Double (double precision floating point number, 8 bytes) Char (character, 1 bytes, ACSII) bool (boolean value, 1 bytes, true/false)

To represent character ‘a’ in memory ‘Var_name’ will occupy address From (1,1) to (2,3) in our 5*6 Memory. (97) 10 =(61) 16 =( ) 2 Syntax: Char var_name = ‘a’; Const int var_name_2 = 12;

Will these make any sense? Now let’s see in contra, we use ‘Hack’ to make our hero undead.

Syntax The following are examples: Float x; Int y=10; Char letter=‘a’; char letter=97; Int num[4]={1,2,3,4}; Char s[5]={‘a’,’b’,’c’,’d’,’e’}; // the size of array is fixed since its creation Definition of ‘=‘ y=y+1; //now y has become 11 letter = letter + 2; //now letter has become ‘c’ S[1]= s[1]+2; // can comment a line /* Can comment a paragrah */

Syntax for operator Introduce some of the most basic: – Int x=5, y=2; – Printf(x/y); //output is 2, larger integer < 2.5 – Printf(x%y); //% can only be used with integer module integer, output is 1 – Int x=5; – Double y=2; – Printf(x/y); //output is 2.5

Now comes logic commands Sequence – Commands are run in sequence Int counter=1; Counter = counter + 1; Counter = counter + 2; Selection – check to see if condition is met. If yes, run. If no, run otherwise. Int counter = 1; If (counter != 1) {counter=counter+1;} Else {counter = counter+2;}

Logic commands (cont.) Loop (for) for(initial condition; end condition; loop commands) Example: For(i=1; i<5; i=i+1) { result=a+b; // i=i+2; } Loop (while) While(ending condition) i=1; While(i<5) { result=a+b; i=i+1; }

We plan to make modules for a program and so comes function A Function is a series of instructions to run. You pass Arguments to a function and it returns a Value. Syntax: Return_type function_name(argument1, argument2…) Int addition(int a, int b) { Int result=a+b; Return result; } Int result = addition(2, 3); // then result=5

Memory use for function Let’s see what happened when run? Int addition(int a, int b) { Int result=a+b; Return result; } Int result = addition(2, 3); // then result=5 We will come about the definition of global variable, local variable when introducing Arduino later. a b result

One step back: machine language Machine language – That machines can directly read, mianly 0/1 Assembly language – That becomes easier to work with Higher-level language – C, C++, Java, Pascal, BASIC Fourth generation language – Visual basic(VB) Assembler Assembly code Object code

1.Edit 2.Preprocess 3.Compile 4.Link 5.Load 6.Execute Disk Loader Linker Compiler Preprocessor Editor Disk Primary Memory CPU Primary Memory 1.Program is created in the editor and stored on disk 2.Preprocessor program processes the code 3.Compiler creates object code and stores it on disk. 5.Loader puts program in memory. 4. Linker links the object code with the libraries 6.CPU takes each instruction and executes it, possibly storing new data values as the program executes Phases of C Programs: A Typical C Program Development Environment

A powerful tool: flow chart I do not make ppt for this part but download an introductory ppt from Internet. Just search ‘programming flow chart’ in Google.

Thanx for your time!!! XD Any Qs?