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/*

    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.

    ***************************************************************************

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    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 exception 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.

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    http://www.FreeRTOS.org - Documentation, latest information, license and

    contact details.

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*/

/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.

NOTE:  This driver is primarily to test the scheduler functionality.  It does

not effectively use the buffers or DMA and is therefore not intended to be

an example of an efficient driver. */

/* Standard include file. */

#include <stdlib.h>

/* Scheduler include files. */

#include "FreeRTOS.h"

#include "queue.h"

#include "task.h"

/* Demo app include files. */

#include "serial.h"

/* Hardware setup. */

#define serOUTPUT                                               0

#define serINPUT                                                1

#define serLOW_SPEED                                    0

#define serONE_STOP_BIT                                 0

#define serEIGHT_DATA_BITS_NO_PARITY    0

#define serNORMAL_IDLE_STATE                    0

#define serAUTO_BAUD_OFF                                0

#define serLOOPBACK_OFF                                 0

#define serWAKE_UP_DISABLE                              0

#define serNO_HARDWARE_FLOW_CONTROL             0

#define serSTANDARD_IO                                  0

#define serNO_IRDA                                              0

#define serCONTINUE_IN_IDLE_MODE                0

#define serUART_ENABLED                                 1

#define serINTERRUPT_ON_SINGLE_CHAR             0

#define serTX_ENABLE                                    1

#define serINTERRUPT_ENABLE                             1

#define serINTERRUPT_DISABLE                    0

#define serCLEAR_FLAG                                   0

#define serSET_FLAG                                             1

/* The queues used to communicate between tasks and ISR's. */

static xQueueHandle xRxedChars;

static xQueueHandle xCharsForTx;

static portBASE_TYPE xTxHasEnded;

/*-----------------------------------------------------------*/

xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )

{

char cChar;

        /* Create the queues used by the com test task. */

        xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );

        xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );

        /* Setup the UART. */

        U2MODEbits.BRGH         = serLOW_SPEED;

        U2MODEbits.STSEL        = serONE_STOP_BIT;

        U2MODEbits.PDSEL        = serEIGHT_DATA_BITS_NO_PARITY;

        U2MODEbits.RXINV        = serNORMAL_IDLE_STATE;

        U2MODEbits.ABAUD        = serAUTO_BAUD_OFF;

        U2MODEbits.LPBACK       = serLOOPBACK_OFF;

        U2MODEbits.WAKE         = serWAKE_UP_DISABLE;

        U2MODEbits.UEN          = serNO_HARDWARE_FLOW_CONTROL;

        U2MODEbits.IREN         = serNO_IRDA;

        U2MODEbits.USIDL        = serCONTINUE_IN_IDLE_MODE;

        U2MODEbits.UARTEN       = serUART_ENABLED;

        U2BRG = (unsigned short)(( (float)configCPU_CLOCK_HZ / ( (float)16 * (float)ulWantedBaud ) ) - (float)0.5);

        U2STAbits.URXISEL       = serINTERRUPT_ON_SINGLE_CHAR;

        U2STAbits.UTXEN         = serTX_ENABLE;

        U2STAbits.UTXINV        = serNORMAL_IDLE_STATE;

        U2STAbits.UTXISEL0      = serINTERRUPT_ON_SINGLE_CHAR;

        U2STAbits.UTXISEL1      = serINTERRUPT_ON_SINGLE_CHAR;

        /* It is assumed that this function is called prior to the scheduler being

        started.  Therefore interrupts must not be allowed to occur yet as they

        may attempt to perform a context switch. */

        portDISABLE_INTERRUPTS();

        IFS1bits.U2RXIF = serCLEAR_FLAG;

        IFS1bits.U2TXIF = serCLEAR_FLAG;

        IPC7bits.U2RXIP = configKERNEL_INTERRUPT_PRIORITY;

        IPC7bits.U2TXIP = configKERNEL_INTERRUPT_PRIORITY;

        IEC1bits.U2TXIE = serINTERRUPT_ENABLE;

        IEC1bits.U2RXIE = serINTERRUPT_ENABLE;

        /* Clear the Rx buffer. */

        while( U2STAbits.URXDA == serSET_FLAG )

        {

                cChar = U2RXREG;

        }

        xTxHasEnded = pdTRUE;

        return NULL;

}

/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )

{

        /* Only one port is supported. */

        ( void ) pxPort;

        /* 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 pdTRUE;

        }

        else

        {

                return pdFALSE;

        }

}

/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )

{

        /* Only one port is supported. */

        ( void ) pxPort;

        /* Return false if after the block time there is no room on the Tx queue. */

        if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )

        {

                return pdFAIL;

        }

        /* A critical section should not be required as xTxHasEnded will not be

        written to by the ISR if it is already 0 (is this correct?). */

        if( xTxHasEnded )

        {

                xTxHasEnded = pdFALSE;

                IFS1bits.U2TXIF = serSET_FLAG;

        }

        return pdPASS;

}

/*-----------------------------------------------------------*/

void vSerialClose( xComPortHandle xPort )

{

}

/*-----------------------------------------------------------*/

void __attribute__((__interrupt__, auto_psv)) _U2RXInterrupt( void )

{

char cChar;

portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

        /* Get the character and post it on the queue of Rxed characters.

        If the post causes a task to wake force a context switch as the woken task

        may have a higher priority than the task we have interrupted. */

        IFS1bits.U2RXIF = serCLEAR_FLAG;

        while( U2STAbits.URXDA )

        {

                cChar = U2RXREG;

                xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );

        }

        if( xHigherPriorityTaskWoken != pdFALSE )

        {

                taskYIELD();

        }

}

/*-----------------------------------------------------------*/

void __attribute__((__interrupt__, auto_psv)) _U2TXInterrupt( void )

{

signed char cChar;

portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

        /* If the transmit buffer is full we cannot get the next character.

        Another interrupt will occur the next time there is space so this does

        not matter. */

        IFS1bits.U2TXIF = serCLEAR_FLAG;

        while( !( U2STAbits.UTXBF ) )

        {

                if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )

                {

                        /* Send the next character queued for Tx. */

                        U2TXREG = cChar;

                }

                else

                {

                        /* Queue empty, nothing to send. */

                        xTxHasEnded = pdTRUE;

                        break;

                }

        }

        if( xHigherPriorityTaskWoken != pdFALSE )

        {

                taskYIELD();

        }

}