test_arduino_serial.c 1.19 KB
#include <avr/io.h> // for the input/output registers
#include <util/delay.h> // for _delay_ms

// For the serial port
#define CPU_FREQ 16000000L // Assume a CPU frequency of 16Mhz

//compile -> makefile

void init_serial(int speed){
	/* Set baud rate */
	UBRR0 = CPU_FREQ/(((unsigned long int)speed)<<4)-1;

	/* Enable transmitter & receiver */
	UCSR0B = (1<<TXEN0 | 1<<RXEN0);

	/* Set 8 bits character and 1 stop bit */
	UCSR0C = (1<<UCSZ01 | 1<<UCSZ00);

	/* Set off UART baud doubler */
	UCSR0A &= ~(1 << U2X0);
}

void send_serial(unsigned char c){
	loop_until_bit_is_set(UCSR0A, UDRE0);
	UDR0 = c;
}

unsigned char get_serial(void) {
	loop_until_bit_is_set(UCSR0A, RXC0);
	return UDR0;
}

// For I/O handling (examples for PIN 8 as output and PIN 2 as input)
void output_init(void){
	DDRB |= 0x01; // PIN 8 as output
}

void output_set(unsigned char value){
	if(value == 0) PORTB &= 0xfe;
	else PORTB |= 0x01;
}

void input_init(void){
	DDRD &= 0xfb; // PIN 2 as input
	PORTD |= 0x04; // Pull-up activated on PIN 2
}

unsigned char input_get(void){
	return ((PIND & 0x04) != 0) ? 1 : 0;
}

// Dummy main
int main(void){
	init_serial(9600);
	while(1){
		send_serial('A');
		_delay_ms(500);
	}
	return 0;
}