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--- en:examples:digi:io [2009/03/25 08:11] – raivo.sell
+++ en:examples:digi:io [2010/02/04 12:28] (current) – removed mikk.leini
@@ Line 1: / Line 1: @@
-====== Digito i/o with Studyboard ======
-{{:et:naited:digi:io.jpg?300|}}
-Studyboard ‚Basic’ includes three outputs (LED) and three inputs (microswitch)
-LEDs are connected to PORTC[3..5] and switches PORTC[0..2].
-This simple examples demonstrates how to switch on LED when pushing appropriate switch.
-==== Connection schema: ====
-{{:et:harjutused:digi:1a_skeem.jpg?500|}}
-==== Example C code: ====
-<code c>
-/* Labor 1 example
-Description: Example works with Studyboard Basic v3
-Press S1 - LED1 goes ON; S2 - LED2 goes ON; S3 - LED3 goes ON
-LED = 0 (ON)  	LED = 1 (OFF)
-S= 0 (ON) 	S= 1 (OFF)
-PORT direction: 1-output	0-input
-Author: Raivo Sell 2008
-*/
-#include <avr/io.h>
-//Definitions for easier bit manipulations
-#define SET(x) |= (1<<x)  //bit high in port x
-#define CLR(x) &=~(1<<x)  //bit low in port x
-int main(void) { //main program
-    DDRC  = 0x38;  // DDRC  0bXX111000
-    PORTC = 0x3F;  // PORTC 0bXX111111
-	//endless loop
-	while(1) {
-		// if button is pressed (pin is low)
-		if (bit_is_clear(PINC, 0))	//Switch S1
-			PORTC CLR(3); //LED 1 ON
-		else if (bit_is_clear(PINC, 1))//Switch S2
-			PORTC CLR(4); //LED 2 ON
-		else if (bit_is_clear(PINC, 2))//Switch S3
-			PORTC CLR(5); //LED 3 ON
-		else // If nothing is pressed
-			PORTC=0xFF;		//All LEDs OFF (LED=1)
-	}
-}
-</code>
-==== Example (short version) ====
-<code c>
-/* Lab 1 example
-Author: Maido Hiiemaa
-Date: 2009
-*/
-#include <avr/io.h>
-int main(void) {
-     DDRC  = 0x38;  //  (00111000)
-     while(1) {
-        PORTC &= ~((PINC << 3) | 0xC7 ); // zeros
-	PORTC |= ((PINC << 3) & ~0xC7 ); // ones
-        }
-}
-</code>
-==== Elliminating bouncing ====
-Source: [[http://www.micahcarrick.com/05-15-2006/avr-tutorial-switch-debounce.html|Micah Carrick tutorial]]
-<code c>
-#include <avr/io.h>
-#include <util/delay.h>
-#define BUTTON_PORT PORTC       /* PORTx - nupu register */
-#define BUTTON_PIN PINC         /* PINx - nupu sisendi register */
-#define BUTTON_BIT PC0          /* nupu sisend/väljund bit */
-int button_is_pressed()
-{
-        /* button is on when BIT is low (0) */
-        if (bit_is_clear(BUTTON_PIN, BUTTON_BIT))
-        {
-                _delay_ms(25); /* de-bouncing delay time */
-                if (bit_is_clear(BUTTON_PIN, BUTTON_BIT)) return 1;
-        }
-        return 0;
-}
-int main (void){
-        /* switch on internel pull-ups */
-        BUTTON_PORT |= _BV(BUTTON_BIT);
-        if (button_is_pressed()){
-                        //  do somthing
-                        // wait if needed
-        }
-}
-</code>

en/examples/digi/io.1237968673.txt.gz · Last modified: 2020/07/20 09:00 (external edit)