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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [msp430_CrossWorks/] [serial/] [serial.c] - Blame information for rev 593

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1 583 jeremybenn
/*
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    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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    ***************************************************************************
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    *                                                                         *
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    * If you are:                                                             *
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    *                                                                         *
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    *    + New to FreeRTOS,                                                   *
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    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
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    *    + Looking for basic training,                                        *
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    *    + Wanting to improve your FreeRTOS skills and productivity           *
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    *                                                                         *
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    * then take a look at the FreeRTOS books - available as PDF or paperback  *
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    *                                                                         *
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    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
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    *                  http://www.FreeRTOS.org/Documentation                  *
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    *                                                                         *
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    * A pdf reference manual is also available.  Both are usually delivered   *
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    * to your inbox within 20 minutes to two hours when purchased between 8am *
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    * and 8pm GMT (although please allow up to 24 hours in case of            *
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    * exceptional circumstances).  Thank you for your support!                *
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    *                                                                         *
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    ***************************************************************************
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    This file is part of the FreeRTOS distribution.
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    FreeRTOS is free software; you can redistribute it and/or modify it under
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    the terms of the GNU General Public License (version 2) as published by the
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    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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    ***NOTE*** The exception to the GPL is included to allow you to distribute
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    a combined work that includes FreeRTOS without being obliged to provide the
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    source code for proprietary components outside of the FreeRTOS kernel.
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    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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    more details. You should have received a copy of the GNU General Public
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    License and the FreeRTOS license exception along with FreeRTOS; if not it
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    can be viewed here: http://www.freertos.org/a00114.html and also obtained
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    by writing to Richard Barry, contact details for whom are available on the
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    FreeRTOS WEB site.
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    1 tab == 4 spaces!
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    http://www.FreeRTOS.org - Documentation, latest information, license and
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    contact details.
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    http://www.SafeRTOS.com - A version that is certified for use in safety
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    critical systems.
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    http://www.OpenRTOS.com - Commercial support, development, porting,
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    licensing and training services.
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*/
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/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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 *
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 * This file only supports UART 1
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 */
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/* Standard includes. */
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#include <stdlib.h>
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "queue.h"
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#include "task.h"
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/* Demo application includes. */
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#include "serial.h"
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/* Constants required to setup the hardware. */
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#define serTX_AND_RX                    ( ( unsigned char ) 0x03 )
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/* Misc. constants. */
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#define serNO_BLOCK                             ( ( portTickType ) 0 )
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/* Enable the UART Tx interrupt. */
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#define vInterruptOn() IFG2 |= UTXIFG1
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/* The queue used to hold received characters. */
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static xQueueHandle xRxedChars;
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/* The queue used to hold characters waiting transmission. */
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static xQueueHandle xCharsForTx;
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static volatile short sTHREEmpty;
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/*-----------------------------------------------------------*/
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xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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{
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unsigned long ulBaudRateCount;
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        /* Initialise the hardware. */
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        /* Generate the baud rate constants for the wanted baud rate. */
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        ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud;
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        portENTER_CRITICAL();
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        {
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                /* Create the queues used by the com test task. */
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                xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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                xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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                /* Reset UART. */
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                UCTL1 |= SWRST;
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                /* Set pin function. */
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                P4SEL |= serTX_AND_RX;
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                /* All other bits remain at zero for n, 8, 1 interrupt driven operation.
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                LOOPBACK MODE!*/
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                U1CTL |= CHAR + LISTEN;
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                U1TCTL |= SSEL1;
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                /* Setup baud rate low byte. */
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                U1BR0 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );
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                /* Setup baud rate high byte. */
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                ulBaudRateCount >>= 8UL;
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                U1BR1 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );
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                /* Enable ports. */
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                ME2 |= UTXE1 + URXE1;
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                /* Set. */
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                UCTL1 &= ~SWRST;
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                /* Nothing in the buffer yet. */
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                sTHREEmpty = pdTRUE;
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                /* Enable interrupts. */
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                IE2 |= URXIE1 + UTXIE1;
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        }
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        portEXIT_CRITICAL();
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        /* Unlike other ports, this serial code does not allow for more than one
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        com port.  We therefore don't return a pointer to a port structure and can
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        instead just return NULL. */
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        return NULL;
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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{
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        /* Get the next character from the buffer.  Return false if no characters
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        are available, or arrive before xBlockTime expires. */
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        if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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        {
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                return pdTRUE;
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        }
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        else
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        {
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                return pdFALSE;
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        }
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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{
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signed portBASE_TYPE xReturn;
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        /* Transmit a character. */
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        portENTER_CRITICAL();
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        {
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                if( sTHREEmpty == pdTRUE )
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                {
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                        /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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                        there are no characters queued to be transmitted - so we can
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                        write the character directly to the shift Tx register. */
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                        sTHREEmpty = pdFALSE;
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                        U1TXBUF = cOutChar;
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                        xReturn = pdPASS;
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                }
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                else
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                {
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                        /* sTHREEmpty is false, so there are still characters waiting to be
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                        transmitted.  We have to queue this character so it gets
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                        transmitted     in turn. */
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                        /* Return false if after the block time there is no room on the Tx
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                        queue.  It is ok to block inside a critical section as each task
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                        maintains it's own critical section status. */
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                        xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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                        /* Depending on queue sizing and task prioritisation:  While we
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                        were blocked waiting to post on the queue interrupts were not
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                        disabled.  It is possible that the serial ISR has emptied the
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                        Tx queue, in which case we need to start the Tx off again
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                        writing directly to the Tx register. */
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                        if( ( sTHREEmpty == pdTRUE ) && ( xReturn == pdPASS ) )
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                        {
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                                /* Get back the character we just posted. */
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                                xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
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                                sTHREEmpty = pdFALSE;
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                                U1TXBUF = cOutChar;
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                        }
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                }
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        }
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        portEXIT_CRITICAL();
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        return pdPASS;
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}
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/*-----------------------------------------------------------*/
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#if configINTERRUPT_EXAMPLE_METHOD == 1
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        /*
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         * UART RX interrupt service routine.
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         */
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        void vRxISR( void ) __interrupt[ UART1RX_VECTOR ]
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        {
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        signed char cChar;
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        portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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                /* Get the character from the UART and post it on the queue of Rxed
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                characters. */
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                cChar = U1RXBUF;
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                xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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                if( xHigherPriorityTaskWoken )
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                {
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                        /*If the post causes a task to wake force a context switch
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                        as the woken task may have a higher priority than the task we have
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                        interrupted. */
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                        taskYIELD();
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                }
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        /* Make sure any low power mode bits are clear before leaving the ISR. */
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        __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
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        }
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        /*-----------------------------------------------------------*/
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        /*
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         * UART Tx interrupt service routine.
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         */
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        void vTxISR( void ) __interrupt[ UART1TX_VECTOR ]
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        {
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        signed char cChar;
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        portBASE_TYPE xTaskWoken = pdFALSE;
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                /* The previous character has been transmitted.  See if there are any
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                further characters waiting transmission. */
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                if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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                {
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                        /* There was another character queued - transmit it now. */
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                        U1TXBUF = cChar;
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                }
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                else
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                {
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                        /* There were no other characters to transmit. */
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                        sTHREEmpty = pdTRUE;
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                }
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        /* Make sure any low power mode bits are clear before leaving the ISR. */
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        __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
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        }
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    /*-----------------------------------------------------------*/
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#elif configINTERRUPT_EXAMPLE_METHOD == 2
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    /* This is a standard C function as an assembly file wrapper is used as an
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    interrupt entry point. */
267
        void vRxISR( void )
268
        {
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        signed char cChar;
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        portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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272
                /* Get the character from the UART and post it on the queue of Rxed
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                characters. */
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                cChar = U1RXBUF;
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                xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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        /*If the post causes a task to wake force a context switch
279
        as the woken task may have a higher priority than the task we have
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        interrupted. */
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        portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
282
        }
283
        /*-----------------------------------------------------------*/
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    /* This is a standard C function as an assembly file wrapper is used as an
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    interrupt entry point. */
287
        void vTxISR( void )
288
        {
289
        signed char cChar;
290
        portBASE_TYPE xTaskWoken = pdFALSE;
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                /* The previous character has been transmitted.  See if there are any
293
                further characters waiting transmission. */
294
 
295
                if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
296
                {
297
                        /* There was another character queued - transmit it now. */
298
                        U1TXBUF = cChar;
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                }
300
                else
301
                {
302
                        /* There were no other characters to transmit. */
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                        sTHREEmpty = pdTRUE;
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                }
305
        }
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#endif /* configINTERRUPT_EXAMPLE_METHOD */
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/*-----------------------------------------------------------*/

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