/*
    FreeRTOS V7.5.2 - Copyright (C) 2013 Real Time Engineers Ltd.

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS provides completely free yet professionally developed,    *
     *    robust, strictly quality controlled, supported, and cross          *
     *    platform software that has become a de facto standard.             *
     *                                                                       *
     *    Help yourself get started quickly and support the FreeRTOS         *
     *    project by purchasing a FreeRTOS tutorial book, reference          *
     *    manual, or both from: http://www.FreeRTOS.org/Documentation        *
     *                                                                       *
     *    Thank you!                                                         *
     *                                                                       *
    ***************************************************************************

    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.  Full license text is available from the following
    link: http://www.freertos.org/a00114.html

    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, books, training, latest versions,
    license and Real Time Engineers Ltd. contact details.

    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool, a DOS
    compatible FAT file system, and our tiny thread aware UDP/IP stack.

    http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
    Integrity Systems to sell under the OpenRTOS brand.  Low cost OpenRTOS
    licenses offer ticketed support, indemnification and middleware.

    http://www.SafeRTOS.com - High Integrity Systems also provide a safety
    engineered and independently SIL3 certified version for use in safety and
    mission critical applications that require provable dependability.

    1 tab == 4 spaces!
*/

/*
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. */
}