/*****************************************************************************
 * Copyright (C) 2008
 * ProbeStar Telematics, LLC
 * All Rights Reserved.  Proprietary and Confidential.
 *============================================================================
 * Serial Initialization & Interrupt Handler
 *----------------------------------------------------------------------------
 * Serial port driver loop using USART, interrupt driven.
*****************************************************************************/

/*****************************************************************************
 * includes
*****************************************************************************/

#include "system.h"
#include "serial.h"
#include "delay.h"
#include "queue.h"

/*****************************************************************************
 * defines
*****************************************************************************/

/*****************************************************************************
 * macros
*****************************************************************************/

/*****************************************************************************
 * structs & typedefs
*****************************************************************************/

/*****************************************************************************
 * global constants
*****************************************************************************/

/*****************************************************************************
 * global variables
*****************************************************************************/

// interrupt driven serial i/o uses queues
SERBANK Queue g_qSerialRx = { 0, 0, 0, 0 };
SERBANK Queue g_qSerialTx = { 0, 0, 0, 0 };

/*****************************************************************************
 * static constants
*****************************************************************************/

/*****************************************************************************
 * static variables
*****************************************************************************/

static LIBBANK BYTE byRx = 0;
static LIBBANK BYTE byTx = 0;

/*****************************************************************************
 * static prototypes
*****************************************************************************/

/*****************************************************************************
 * C functions
*****************************************************************************/

void SerialInit( void )
{
	// fix these
	RC6 = 1;
	RC7 = 1;
	TRISC6 = 0;
	TRISC7 = 1;

	// baud rate
	SerialBaud( BAUD );

	// asynchronous serial
	// recv, 8 bits, continuous
	RCSTA = 0b10010000;
	// xmit, 8 bits, high speed
	TXSTA = 0b00100110;

	CREN = 0;
	CREN = 1;
}

void SerialAlloc( BYTE *pbyTx, BYTE nTx, BYTE *pbyRx, BYTE nRx )
{
	QueueAlloc( &g_qSerialTx, pbyTx, nTx );
	QueueAlloc( &g_qSerialRx, pbyRx, nRx );
	if ( nTx )
	{
		RCIE = 1;
#ifdef _PIC18
		RCIP = 1;
#endif
	}
	if ( nRx )
	{
		TXIE = 0;	// turned on by putch()
#ifdef _PIC18
		TXIP = 1;
#endif
	}
	RCIF = TXIF = 0;
}

void SerialClear( void )
{
	CREN = 0;
	CREN = 1;
	QueueClear( &g_qSerialTx );
	QueueClear( &g_qSerialRx );
	getchflush();
}

void SerialHandler( void )
{
	// RC7/RX
	if ( RCIF )
	{
		// check queue, lose a byte if necessary
		while ( _QueueFull( g_qSerialRx ) )
			_QueueGet( g_qSerialRx, byRx );

		// read char
		byRx = RCREG;
                _QueuePut( g_qSerialRx, byRx );

		// doesn't handle overflow, so app had better have big buffer
		if ( OERR )
		{
			// overrun error (lost data)
			CREN = 0;
			CREN = 1;
		}
		RCIF = 0;
	}
	// RC6/TX
	if ( TXIF )
	{
		// ready to xmit
		byTx = _QueueCount( g_qSerialTx );
		if ( byTx )
		{
			// output from queue
			_QueueGet( g_qSerialTx, TXREG );
			byTx--;
		}
		if ( byTx == 0 )
		{
			// nothing left, disable
			TXIE = 0;
		}
		TXIF = 0;
	}
}