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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [Cygnal/] [serial/] [serial.c] - Blame information for rev 584

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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 FOR DEMO PURPOSES */
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#include <stdlib.h>
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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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#include "serial.h"
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/* Constants required to setup the serial control register. */
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#define ser8_BIT_MODE                   ( ( unsigned char ) 0x40 )
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#define serRX_ENABLE                    ( ( unsigned char ) 0x10 )
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/* Constants to setup the timer used to generate the baud rate. */
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#define serCLOCK_DIV_48                 ( ( unsigned char ) 0x03 )
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#define serUSE_PRESCALED_CLOCK  ( ( unsigned char ) 0x10 )
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#define ser8BIT_WITH_RELOAD             ( ( unsigned char ) 0x20 )
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#define serSMOD                                 ( ( unsigned char ) 0x10 )
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static xQueueHandle xRxedChars;
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static xQueueHandle xCharsForTx;
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data static unsigned portBASE_TYPE uxTxEmpty;
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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 ulReloadValue;
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const portFLOAT fBaudConst = ( portFLOAT ) configCPU_CLOCK_HZ * ( portFLOAT ) 2.0;
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unsigned char ucOriginalSFRPage;
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        portENTER_CRITICAL();
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        {
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                ucOriginalSFRPage = SFRPAGE;
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                SFRPAGE = 0;
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                uxTxEmpty = pdTRUE;
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                /* Create the queues used by the com test task. */
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                xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
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                xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
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                /* Calculate the baud rate to use timer 1. */
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                ulReloadValue = ( unsigned long ) ( ( ( portFLOAT ) 256 - ( fBaudConst / ( portFLOAT ) ( 32 * ulWantedBaud ) ) ) + ( portFLOAT ) 0.5 );
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                /* Set timer one for desired mode of operation. */
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                TMOD &= 0x08;
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                TMOD |= ser8BIT_WITH_RELOAD;
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                SSTA0 |= serSMOD;
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                /* Set the reload and start values for the time. */
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                TL1 = ( unsigned char ) ulReloadValue;
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                TH1 = ( unsigned char ) ulReloadValue;
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                /* Setup the control register for standard n, 8, 1 - variable baud rate. */
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                SCON = ser8_BIT_MODE | serRX_ENABLE;
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                /* Enable the serial port interrupts */
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                ES = 1;
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                /* Start the timer. */
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                TR1 = 1;
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                SFRPAGE = ucOriginalSFRPage;
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        }
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        portEXIT_CRITICAL();
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        /* Unlike some 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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void vSerialISR( void ) interrupt 4
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{
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char cChar;
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portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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        /* 8051 port interrupt routines MUST be placed within a critical section
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        if taskYIELD() is used within the ISR! */
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        portENTER_CRITICAL();
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        {
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                if( RI )
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                {
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                        /* Get the character and post it on the queue of Rxed characters.
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                        If the post causes a task to wake force a context switch if the woken task
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                        has a higher priority than the task we have interrupted. */
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                        cChar = SBUF;
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                        RI = 0;
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                        xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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                }
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                if( TI )
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                {
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                        if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == ( portBASE_TYPE ) pdTRUE )
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                        {
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                                /* Send the next character queued for Tx. */
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                                SBUF = cChar;
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                        }
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                        else
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                        {
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                                /* Queue empty, nothing to send. */
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                                uxTxEmpty = pdTRUE;
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                        }
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                        TI = 0;
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                }
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                if( xHigherPriorityTaskWoken )
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                {
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                        portYIELD();
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                }
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        }
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        portEXIT_CRITICAL();
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}
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/*-----------------------------------------------------------*/
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portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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{
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        /* There is only one port supported. */
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        ( void ) pxPort;
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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 ( portBASE_TYPE ) pdTRUE;
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        }
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        else
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        {
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                return ( portBASE_TYPE ) pdFALSE;
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        }
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}
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/*-----------------------------------------------------------*/
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portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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{
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portBASE_TYPE xReturn;
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        /* There is only one port supported. */
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        ( void ) pxPort;
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        portENTER_CRITICAL();
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        {
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                if( uxTxEmpty == pdTRUE )
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                {
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                        SBUF = cOutChar;
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                        uxTxEmpty = pdFALSE;
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                        xReturn = ( portBASE_TYPE ) pdTRUE;
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                }
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                else
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                {
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                        xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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                        if( xReturn == ( portBASE_TYPE ) pdFALSE )
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                        {
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                                xReturn = ( portBASE_TYPE ) pdTRUE;
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                        }
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                }
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        }
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        portEXIT_CRITICAL();
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        return xReturn;
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}
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/*-----------------------------------------------------------*/
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void vSerialClose( xComPortHandle xPort )
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{
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        /* Not implemented in this port. */
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        ( void ) xPort;
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}
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/*-----------------------------------------------------------*/
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