ulogger

ulogger.c

#ifndef F_CPU
#define F_CPU       16000000UL
#endif

#include <avr/io.h>
#include <util/delay.h>
#include <stdlib.h>

#define TEMPERATUR  PF0
#define BUTTON      PF1
#define WATER       PF2
#define TRIGGER     PF3
#define ECHO        PF4

char buffer[20];

/*
 * Init pins
 */

void init_pins(void) {
    // set all pins to INPUT except TRIGGER
    DDRF = (0x00 | (1 << TRIGGER));
    // activate PULLUPS for all inputs except TRIGGER
    PORTF = (0xff & ~(1 << TRIGGER));
}

/*
 * ADC
 */

void init_adc(void)
{
  ADMUX = (1<<REFS0);    
  ADCSRA = (1<<ADPS1) | (1<<ADPS0);     // Frequenzvorteiler
  ADCSRA |= (1<<ADEN);                  // ADC aktivieren
  ADCSRA |= (1<<ADSC);                  // eine ADC-Wandlung 
  while (ADCSRA & (1<<ADSC) );          // auf Abschluss der Konvertierung warten
  (void) ADCW;
}
 
uint16_t read_adc( uint8_t channel )
{
  ADMUX = (ADMUX & ~(0x1F)) | (channel & 0x1F);
  ADCSRA |= (1<<ADSC);            // eine Wandlung "single conversion"
  while (ADCSRA & (1<<ADSC) );    // auf Abschluss der Konvertierung warten
  return ADCW;                    // ADC auslesen und zurückgeben
}

uint16_t read_avg_adc( uint8_t channel, uint8_t nsamples )
{
  uint32_t sum = 0;
  for (uint8_t i = 0; i < nsamples; ++i ) { 
    sum += read_adc( channel );
  }
  return (uint16_t)( sum / nsamples );
}
void init_serial(void) {
  uint16_t baudrate = 9600;
  uint16_t baud = (F_CPU / 8 / baudrate - 1) / 2;
  UBRR0H = (uint8_t) (baud >> 8);
  UBRR0L = (uint8_t) (baud & 0x0ff);
  UCSR0B |= (1 << 3); /* TXEN */
  UCSR0B |= (1 << 4); /* RXEN */
  UCSR0B |= (1 << 7); /* RXCIE */
  UCSR0C |=  (1 << 1); /* UCSZ0 = 1 */
  UCSR0C |=  (1 << 2); /* UCSZ1 = 1 */
  UCSR0B &= ~(1 << 2); /* UCSZ2 = 0 */
  UCSR0C &= ~(1 << 4); /* UPM0 = 0 */
  UCSR0C &= ~(1 << 5); /* UPM1 = 0 */
  UCSR0C |=  (1 << 3); /* USBS = 1 */
}

void uart_putc(char c) {
    while (!(UCSR0A & (1<<UDRE0)));
    UDR0 = c;
} 

void uart_puts(char* s) {
    while(*s) {
        uart_putc(*s);
        s++;
    }
}

char getc(void)
{
    while (!(UCSR0A & (1<<RXC0)));
    return UDR0;
}

/*
 * Board functions
 */

int button_pressed(void) {
    return (PINF & (1 << BUTTON));
}

int water_alert(void) {
    return (PINF & (1 << WATER));
}

int measure_distance(void) {
    int t = 0;
    PORTF |= (1 << TRIGGER);
    _delay_ms(20);
    PORTF &= ~(1 << TRIGGER);
    while((PINF & (1 << ECHO)) == 0);
    while((PINF & (1 << ECHO))) {
        _delay_us(1);
        t++;
    }
    return t / 58;
}

int main(void) {
    init_pins();
    init_adc();
    init_serial();
    while(1) {

        _delay_ms(500);

        if(button_pressed()) {
            uart_puts("Button pressed");
            uart_putc('\n');
        }

        if(water_alert()) {
            uart_puts("Water alert");
            uart_putc('\n');
        }

        uart_puts("Analog value: ");
        uart_puts(itoa(read_avg_adc(0,20),buffer,10));
        uart_putc('\n');

        uart_puts("Distance in cm: ");
        uart_puts(itoa(measure_distance(),buffer,10));
        uart_putc('\n');

    }

    return 0;
}