/*
    FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.

    FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT 
    http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS tutorial books are available in pdf and paperback.        *
     *    Complete, revised, and edited pdf reference manuals are also       *
     *    available.                                                         *
     *                                                                       *
     *    Purchasing FreeRTOS documentation will not only help you, by       *
     *    ensuring you get running as quickly as possible and with an        *
     *    in-depth knowledge of how to use FreeRTOS, it will also help       *
     *    the FreeRTOS project to continue with its mission of providing     *
     *    professional grade, cross platform, de facto standard solutions    *
     *    for microcontrollers - completely free of charge!                  *
     *                                                                       *
     *    >>> See http://www.FreeRTOS.org/Documentation for details. <<<     *
     *                                                                       *
     *    Thank you for using FreeRTOS, and thank you for your support!      *
     *                                                                       *
    ***************************************************************************


    This file is part of the FreeRTOS distribution.

    FreeRTOS is free software; you can redistribute it and/or modify it under
    the terms of the GNU General Public License (version 2) as published by the
    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
    >>>NOTE<<< The modification to the GPL is included to allow you to
    distribute a combined work that includes FreeRTOS without being obliged to
    provide the source code for proprietary components outside of the FreeRTOS
    kernel.  FreeRTOS is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
    more details. You should have received a copy of the GNU General Public
    License and the FreeRTOS license exception along with FreeRTOS; if not it
    can be viewed here: http://www.freertos.org/a00114.html and also obtained
    by writing to Richard Barry, contact details for whom are available on the
    FreeRTOS WEB site.

    1 tab == 4 spaces!
    
    ***************************************************************************
     *                                                                       *
     *    Having a problem?  Start by reading the FAQ "My application does   *
     *    not run, what could be wrong?"                                     *
     *                                                                       *
     *    http://www.FreeRTOS.org/FAQHelp.html                               *
     *                                                                       *
    ***************************************************************************

    
    http://www.FreeRTOS.org - Documentation, training, latest versions, license 
    and contact details.  
    
    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool.

    Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell 
    the code with commercial support, indemnification, and middleware, under 
    the OpenRTOS brand: http://www.OpenRTOS.com.  High Integrity Systems also
    provide a safety engineered and independently SIL3 certified version under 
    the SafeRTOS brand: http://www.SafeRTOS.com.
*/

/*
Changes from V3.0.0
	+ ISRcode removed. Is now pulled inline to reduce stack-usage.

Changes from V3.0.1
*/

/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */

/* Scheduler header files. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"

#include "serial.h"

/* Hardware pin definitions. */
#define serTX_PIN				bTRC6
#define serRX_PIN				bTRC7

/* Bit/register definitions. */
#define serINPUT				( 1 )
#define serOUTPUT				( 0 )
#define serINTERRUPT_ENABLED 	( 1 )

/* All ISR's use the PIC18 low priority interrupt. */
#define	serLOW_PRIORITY			( 0 )

/*-----------------------------------------------------------*/

/* Queues to interface between comms API and interrupt routines. */
xQueueHandle xRxedChars; 
xQueueHandle xCharsForTx;
portBASE_TYPE xHigherPriorityTaskWoken;

/*-----------------------------------------------------------*/

xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned char ucQueueLength )
{
	unsigned short usSPBRG;
	
	/* Create the queues used by the ISR's to interface to tasks. */
	xRxedChars = xQueueCreate( ucQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
	xCharsForTx = xQueueCreate( ucQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );

	portENTER_CRITICAL();

	/* Setup the IO pins to enable the USART IO. */
	serTX_PIN	= serINPUT;		// YES really! See datasheet
	serRX_PIN	= serINPUT;

	/* Set the TX config register. */
	TXSTA = 0b00100000;
		//	  ||||||||--bit0: TX9D	= n/a
		//	  |||||||---bit1: TRMT	= ReadOnly
		//	  ||||||----bit2: BRGH	= High speed
		//	  |||||-----bit3: SENDB = n/a
		//	  ||||------bit4: SYNC	= Asynchronous mode
		//	  |||-------bit5: TXEN	= Transmit enable
		//	  ||--------bit6: TX9	= 8-bit transmission
		//	  |---------bit7: CSRC	= n/a

	/* Set the Receive config register. */
	RCSTA = 0b10010000;
		//	  ||||||||--bit0: RX9D	= ReadOnly
		//	  |||||||---bit1: OERR	= ReadOnly
		//	  ||||||----bit2: FERR	= ReadOnly
		//	  |||||-----bit3: ADDEN	= n/a
		//	  ||||------bit4: CREN	= Enable receiver
		//	  |||-------bit5: SREN	= n/a
		//	  ||--------bit6: RX9	= 8-bit reception
		//	  |---------bit7: SPEN	= Serial port enabled

	/* Calculate the baud rate generator value.
	   We use low-speed (BRGH=0), the formula is
	   SPBRG = ( ( FOSC / Desired Baud Rate ) / 64 ) - 1 */
	usSPBRG = ( ( APROCFREQ / ulWantedBaud ) / 64 ) - 1;
	if( usSPBRG > 255 )
	{
		SPBRG = 255;
	}
	else
	{
		SPBRG = usSPBRG;
	}

	/* Set the serial interrupts to use the same priority as the tick. */
	bTXIP = serLOW_PRIORITY;
	bRCIP = serLOW_PRIORITY;

	/* Enable the Rx interrupt now, the Tx interrupt will get enabled when
	we have data to send. */
	bRCIE = serINTERRUPT_ENABLED;
	
	portEXIT_CRITICAL();

	/* Unlike other ports, this serial code does not allow for more than one
	com port.  We therefore don't return a pointer to a port structure and 
	can	instead just return NULL. */
	return NULL;
}
/*-----------------------------------------------------------*/

xComPortHandle xSerialPortInit( eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits, unsigned char ucBufferLength )
{
	/* This is not implemented in this port.
	Use xSerialPortInitMinimal() instead. */
	return NULL;
}
/*-----------------------------------------------------------*/

portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, char *pcRxedChar, portTickType xBlockTime )
{
	/* Get the next character from the buffer.  Return false if no characters
	are available, or arrive before xBlockTime expires. */
	if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
	{
		return ( char ) pdTRUE;
	}

	return ( char ) pdFALSE;
}
/*-----------------------------------------------------------*/

portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, char cOutChar, portTickType xBlockTime )
{
	/* Return false if after the block time there is no room on the Tx queue. */
	if( xQueueSend( xCharsForTx, ( const void * ) &cOutChar, xBlockTime ) != ( char ) pdPASS )
	{
		return pdFAIL;
	}

	/* Turn interrupt on - ensure the compiler only generates a single 
	instruction for this. */
	bTXIE = serINTERRUPT_ENABLED;

	return pdPASS;
}
/*-----------------------------------------------------------*/

void vSerialClose( xComPortHandle xPort )
{
	/* Not implemented for this port.
	To implement, turn off the interrupts and delete the memory
	allocated to the queues. */
}