///////////////////////////////////////////////////////////////////////////
// Name: uart.c
// Author: B. Gian James  <gian@BattleDroids.net>
// Description:  A little bit of code to implement reading and writing 
//               from a hardware UART/USART.
//
// $Id: uart.c,v 1.1.1.1 2009/08/19 06:09:42 gian Exp $
///////////////////////////////////////////////////////////////////////////

#include "uart.h"

static void uart_2400(void);
static void uart_9600(void);
static void uart_38400(void);
static void uart_57600(void);


// Initialize the UART to b Bd, tx/rx, 8N1, asynchronous mode.
// TODO: Add support for bit size, parity, stop bits, etc
void
USART_init(uint8_t b, uint8_t rxtx)
{
	switch(b)
	{
	case BAUD_2400:		uart_2400(); break;
	case BAUD_38400:	uart_38400(); break;
	case BAUD_57600:	uart_57600(); break;
	case BAUD_9600:
	default:
		uart_9600(); break;
	}

	// Enable Rx/Tx in register UCSR0B
	UCSR0B 	= (1<<RXEN0)|(1<<TXEN0);

	// rx/tx interrupt vectors
	if (rxtx) {
		if (rxtx & INT_RX)
			BSET(UCSR0B,RXCIE0);
		if (rxtx & INT_TX)
			BSET(UCSR0B,TXCIE0);
	}
}

// USART_transmit
// Send data to USART buffer for transmission
void
USART_tx(unsigned char data)
{
	// Check UDRE0 in UCSR0A.  If 1, then buffer empty.
	loop_until_bit_is_set(UCSR0A,UDRE0);
	UDR0 = data;
}
void
USART_tx_S(const char * data)
{
	while(*data != 0x00)
		USART_tx(*(data++));
}


// USART_receive
// 
unsigned char
USART_rx(void)
{
	loop_until_bit_is_set(UCSR0A,RXC0);
	return UDR0;
}

static void
uart_2400(void)
{
	#define BAUD 2400
	#include <util/setbaud.h>
	UBRR0H = UBRRH_VALUE;
	UBRR0L = UBRRL_VALUE;
	#if USE_2X
	UCSR0A |= (1 << U2X0);
	#else
	UCSR0A &= ~(1 << U2X0);
	#endif
}


static void
uart_9600(void)
{
	#undef BAUD
	#define BAUD 9600
	#include <util/setbaud.h>
	UBRR0H = UBRRH_VALUE;
	UBRR0L = UBRRL_VALUE;
	#if USE_2X
	UCSR0A |= (1 << U2X0);
	#else
	UCSR0A &= ~(1 << U2X0);
	#endif
}

static void
uart_38400(void)
{
	#undef BAUD // avoid compiler warning
	#define BAUD 38400
	#include <util/setbaud.h>
	UBRR0H = UBRRH_VALUE;
	UBRR0L = UBRRL_VALUE;
	#if USE_2X
	UCSR0A |= (1 << U2X0);
	#else
	UCSR0A &= ~(1 << U2X0);
	#endif
}
static void
uart_57600(void)
{
	#undef BAUD // avoid compiler warning
	#define BAUD 57600
	#include <util/setbaud.h>
	UBRR0H = UBRRH_VALUE;
	UBRR0L = UBRRL_VALUE;
	#if USE_2X
	UCSR0A |= (1 << U2X0);
	#else
	UCSR0A &= ~(1 << U2X0);
	#endif
}