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avr_demo/digital_read/main.c

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/*
* Digital read 8bit data from PORTD3..7 PORTD0..1 (Arduino digital ports 3..9)
* and output it as binary string (10001101) to serial. Floating state is high.
* Connect pin to ground to set it low.
*
* Led at Arduino digital 13 (PORTB5). Cause we all love blinken leds!
*
* To compile and upload run: make clean; make; make program;
*
* Copyright 2011 Mika Tuupola
*
* Licensed under the MIT license:
* http://www.opensource.org/licenses/mit-license.php
*
*/
#ifndef F_CPU
#define F_CPU 16000000UL
#endif
#include <stdlib.h>
#include <avr/io.h>
#include <stdio.h>
#include <util/delay.h>
#include <stdint.h>
#include <avr/sfr_defs.h>
#include "main.h"
#include "uart.h"
void init(void) {
/* Make PORTD2..7 PORTD0..1 (Arduino digital 3..11) input by clearing bits in DDR */
DDRD &= ~(_BV(PORTD2) | _BV(PORTD3) | _BV(PORTD4) | _BV(PORTD5) | _BV(PORTD6) | _BV(PORTD7));
DDRB &= ~(_BV(PORTB0) | _BV(PORTB1));
/* In input mode, when pull-up is enabled, default state of pin becomes 1. So even if */
/* you dont connect anything to pin and if you try to read it, it will read as 1. Now, */
/* when you externally drive that pin to zero(i.e. connect to ground / or pull-down), */
/* only then it will be read as 0. */
/* Enable pullups by setting bits in PORT. Default state is now high. */
PORTD |= (_BV(PORTD2) | _BV(PORTD3) | _BV(PORTD4) | _BV(PORTD5) | _BV(PORTD6) | _BV(PORTD7));
PORTB |= (_BV(PORTB0) | _BV(PORTB1));
/* Disable pullups by clearing bits in PORT. Default state is now low. */
/*
PORTD &= ~(_BV(PORTD2) | _BV(PORTD3) | _BV(PORTD4) | _BV(PORTD5) | _BV(PORTD6) | _BV(PORTD7));
PORTB &= ~(_BV(PORTB0) | _BV(PORTB1));
*/
/* Make PORTB5 (Arduino digital 13) an output by setting bit in DDR. */
DDRB |= _BV(PORTB5);
}
int digital_read(int input_register, int pin) {
return bit_is_set(input_register, pin) != 0 ? 1 : 0;
}
/*
void digital_write(int input_register, int pin) {
input_register |= _BV(pin);
}
*/
int main(void) {
init();
uart_init();
stdout = &uart_output;
stdin = &uart_input;
int value;
//char buffer[9];
while (1) {
/* Blink led by toggling state of PORTB5 (Arduino digital 13). */
PORTB ^= _BV(PORTB5);
/*
puts("PINB");
value = PINB;
itoa(value, buffer, 2);
puts(buffer);
*/
value = digital_read(PIND, PIND2);
printf("%d", value);
value = digital_read(PIND, PIND3);
printf("%d", value);
value = digital_read(PIND, PIND4);
printf("%d", value);
value = digital_read(PIND, PIND5);
printf("%d", value);
value = digital_read(PIND, PIND6);
printf("%d", value);
value = digital_read(PIND, PIND7);
printf("%d", value);
value = digital_read(PINB, PINB0);
printf("%d", value);
value = digital_read(PINB, PINB1);
printf("%d\n", value);
_delay_ms(500);
}
return 0;
}