Imperativ Programming. morning (again) Jens Dalsgaard Nielsen Aalborg University (1/24)

Transcription

1 Imperativ Programming morning (again) Jens Dalsgaard Nielsen Aalborg University (1/24)

2 message Changed timing today Jens Dalsgaard Nielsen Aalborg University (2/24)

3 Jens Dalsgaard Nielsen Aalborg University (3/24)

4 Imperative Programming Jens Dalsgaard Nielsen Aalborg University (4/24)

5 1)hidden setup (in Arduino) 2)setup 3)loop 4)loop again 5)... Jens Dalsgaard Nielsen Aalborg University (5/24)

6 no One(well it s no two) APPLICATION spec initalise system BLINK with LED on pin 13: ON 1 sec, OFF 1 sec ALGORITM 1) initalise_system: LED interface 2) LED ON 3) wait 1 sec 4) LED OFF 5) wait 1 sec 6) go to 2) (done pr automatic by loop function) HW: arduino ( you got one)... Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (6/24)

7 Breadboard LED Jens Dalsgaard Nielsen Aalborg University (7/24)

8 LED and pins Jens Dalsgaard Nielsen Aalborg University (8/24)

9 let s code pinmode(pin, mode) you can digitalwrite you can digitalwrite(13, HIGH); digitalwrite(13, LOW); wait some time pinmode(13, OUTPUT); pinmode(13, INPUT); delay(1234); // wait 1234 milli seconds (= 1,234 sec) datz all coding now Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (9/24)

10 one example void setup() { pinmode( 13, OUTPUT); void loop() { digitalwrite(13, HIGH ); // LED ON delay(1000); // wait 1 sec digitalwrite(13, LOW ); // LED OFF delay (1000); // wait 1 sec /* function end. Lets loop */ Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (10/24)

11 Imperative Imperativ betyder bydemåde You decide what and when an action takes place Oral programming we say LEDON and wait one second LEDOFF and wait one second repeat Simple functionality ==> function paradigme in coding Jens Dalsgaard Nielsen Aalborg University (11/24)

12 code more structured void setup() { pinmode( 13, OUTPUT); void LEDONandWaitOneSecond() { digitalwrite(13, HIGH ); // LED ON delay(1000); void LEDOFFandWaitOneSecond() { digitalwrite(13, LOW ); // LED OFF delay(1000); void loop() { LEDONandWaitOneSecond(); LEDOFFandWaitOneSecond(); Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (12/24)

13 code again void setup() { pinmode( 13, OUTPUT); void LEDONandWait () { digitalwrite(13, HIGH ); // taend LED delay(1000); void LEDOFFandWait() { digitalwrite(13, LOW ); // taend LED delay(1000); void blinkled () { LEDONandWait(); LEDOFFandWait(); void loop() { blinkled(); Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (13/24)

14 Variables Integer (counting numbers) Unsigned versions int anumber; // > 0 > long anothernumber; // ca 2 bill to 2 bill char a littnumber; // 128 > 0 > 127 unsigned int positiven; // 0 > unsigned long laaarge; // 0 > 4 bill unsigned char; // 0 > 255 JUST ONE EXAMPLE UNSIGNED INT Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (14/24)

15 decision what if??? what if a number is larger than 100 then I will go this or if not I will do something else int anumber; if (anumber > 100) { // boolean expression // then part else { // else part Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (15/24)

16 boolean expresion evaluates to TRUE or FALSE In C FALSE equal numerical value 0 and TRUE everything else (doch datz life) int x,y; if ( (a<4) && ( 3 <= y) ) if a less than 4 AND y is greater or equal to 3 &&: boolean/logic AND : boolean/logic OR if ( (a<4) ( 3 <= y) ) Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (16/24)

17 and you can combine as... int a,b,y,c; if ( (a < 5) && (y< 3) (b>44) && (c <= 41) ) YOU CAN DO IT AS COMPLICATED YOU WANT. dence Precedence of operators. Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (17/24)

18 A subset * / + < > <= >= && = we all know x = 2 * / 3; IS = 11 because we do * / before + : precedence of operators PLEASE USE PARANTESES ALL TIME: x = (2 * 4) + (9 / 3); // much more readable Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (18/24)

19 real life : ( Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (19/24)

20 while versus for while is like loop in Arduino while this it true loophere int counter = 0; while (counter < 10) { Serial.println(counter); counter++; // increment counter by one we will se Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (20/24)

21 for loop loop in another way for (int i = 0 ; i < 10 ; i++) { Serial.println(i); We will see Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (21/24)

22 Arrays When we can loop a number of times it may be nice to have variables in same way. int data[10]; // 10 ints for (int i = 0; i < 10 ; i++ ) { data[i] = i*2; for (int i = 0; i < 10 ; i++ ) { Serial.println(data[i]); data[10] = data[0], data[1],..., data[9] ARRAYS ALWAYS START WITH ELEMENT 0!!!!!!!!! Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (22/24)

23 digital input HIGH or LOW HIGH ~ 5V (or 3.3V) LOW ~ 0V like digital output pinmode(12, INPUT); // datz all if (digitalread(12) == HIGH) { Serial.println( HIGH ); else { Serial.println( LOW ); Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (23/24)

24 pullup open input ==???? in value We need to have a default value pinmode(12,output_pullup); Jens Dalsgaard Nielsen (jdn@es.aau.dk) Aalborg University (24/24)