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avr_demo/digital_read/main.c
2011-09-16 22:50:37 +03:00

106 lines
2.5 KiB
C

/*
* 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
*
*/
#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"
#ifndef F_CPU
#define F_CPU 16000000UL
#endif
#define BAUD 9600
#include <util/setbaud.h>
volatile uint8_t interrupts;
char buffer[1];
static void uart_init(void) {
UBRR0H = UBRRH_VALUE;
UBRR0L = UBRRL_VALUE;
UCSR0C = _BV(UCSZ01) | _BV(UCSZ00);
UCSR0B = _BV(RXEN0) | _BV(TXEN0);
}
static int uart_putchar(char c, FILE *stream) {
loop_until_bit_is_set(UCSR0A, UDRE0);
UDR0 = c;
return 0;
}
static int uart_getchar(FILE *stream) {
loop_until_bit_is_set(UCSR0A, RXC0);
return UDR0;
}
static int digital_read(sfr, bit) {
return bit_is_set(sft, bit) && 1;
}
void init(void) {
/* Make PORTD3..7 PORTD0..1 (Arduino digital 3..9) input by clearing bits in DDR */
DDRD &= ~(_BV(PORTD2) | _BV(PORTD3) | _BV(PORTD4) | _BV(PORTD5) | _BV(PORTD6) | _BV(PORTD7));
DDRB &= ~(_BV(PORTB0) | _BV(PORTB1));
/* Disable pullups by clearing bits in PORT. Default state is now low. */
/*
PORTD &= ~(_BV(PORTD3) | _BV(PORTD4) | _BV(PORTD5) | _BV(PORTD6) | _BV(PORTD7));
PORTB &= ~(_BV(PORTB0) | _BV(PORTB1));
*/
/* 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));
/* Make PORTB5 (Arduino digital 13) an output by setting bit in DDR. */
DDRB |= _BV(PORTB5);
}
int main(void) {
init();
uart_init();
stdout = &output;
stdin = &input;
uint8_t value;
char buffer[9];
while (1) {
/* Blink led by toggling state of PORTB5 (Arduino digital 13). */
PORTB ^= _BV(PORTB5);
/* Take 8bit value from PORTD3..7 PORTD0..1 */
value = (PIND >> 2) + (PINB << 6);
itoa(value, buffer, 2);
puts(buffer);
_delay_ms(500);
}
return 0;
}