/********************************************************************************
                                Includes
********************************************************************************/
#include <avr/io.h>
#include <stdio.h>
#include <stdbool.h>

/********************************************************************************
                                Macros and Defines
********************************************************************************/
#define BAUD 19200
#define MYUBRR F_CPU/16/BAUD-1

/********************************************************************************
                                Function Prototypes
********************************************************************************/
void usart_init(uint16_t ubrr);
char usart_getchar( void ); 
void usart_putchar( char data ); 
void usart_pstr(char *s);
unsigned char usart_kbhit(void);

/********************************************************************************
                                Main
********************************************************************************/
int main( void )
{
	unsigned char input;
	uint8_t value;
	value = 0;

     // configure PORTA as output
    DDRA = 0xFF;
	// setup PORTB data direction as an input
	DDRB = 0;
	// make sure it is high impedance and will not source
	PORTB = 0;

	// fire up the usart
	usart_init ( MYUBRR );

	// dump some strings to the screen at power on
	usart_pstr("Ready to rock and roll!\n\r");
	usart_pstr("Type in a character, and I will transpose it up by 1:\n\r");
	
	// main loop
	while(true) {
		// if a key has been pressed, then process it
		if(usart_kbhit()) {
			input = usart_getchar();
			switch (input) {
				case 'a':
					usart_pstr("You pressed 'a'. Turning all lights on.\n\r");
					PORTA=0x00;
					break;
				case 'b':
					usart_pstr("You pressed 'b'. Turning all lights off.\n\r");
					PORTA=0xFF;
					break;
				default:
					usart_pstr("I don't know what to do with that key.\n\r");
			}
		}
		
		// hold down SW0 to count binary patterns to the LEDs
		if(bit_is_clear(PINB,PB0)) {
			//usart_pstr("Incrementing value and setting up the lights.\n\r");
			value++;
			PORTA = ~value;
		}

		// hold down SW1 to invert the LED's
		if(bit_is_clear(PINB,PB1)) {
			//usart_pstr("Inverting the light values.\n\r");
			PORTA = ~PORTA;
		}
	}
	return 0;
}

/********************************************************************************
                                usart Related
********************************************************************************/
void usart_init( uint16_t ubrr) {
	// Set baud rate
	UBRRH = (uint8_t)(ubrr>>8);
	UBRRL = (uint8_t)ubrr;
	// Enable receiver and transmitter
	UCSRB = (1<<RXEN)|(1<<TXEN);
	// Set frame format: 8data, 1stop bit
	UCSRC = (1<<URSEL)|(3<<UCSZ0);
}

void usart_putchar(char data) { 
	// Wait for empty transmit buffer
	while ( !(UCSRA & (_BV(UDRE))) );
	// Start transmission
	UDR = data; 
}

char usart_getchar(void) { 
	// Wait for incomming data
	while ( !(UCSRA & (_BV(RXC))) );
	// Return the data
	return UDR;
} 

void usart_pstr(char *s) {
    // loop through entire string
	while (*s) {  
        usart_putchar(*s);
        s++;
    }
}

unsigned char usart_kbhit(void) {
	//return nonzero if char waiting  polled version
	unsigned char b;
	b=0;
	if(UCSRA & (1<<RXC)) b=1;
	return b;
}