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251 lines
8.6 KiB
C
251 lines
8.6 KiB
C
/*
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FreeRTOS.org V4.7.0 - Copyright (C) 2003-2007 Richard Barry.
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This file is part of the FreeRTOS.org distribution.
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FreeRTOS.org is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FreeRTOS.org is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FreeRTOS.org; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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A special exception to the GPL can be applied should you wish to distribute
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a combined work that includes FreeRTOS.org, without being obliged to provide
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the source code for any proprietary components. See the licensing section
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of http://www.FreeRTOS.org for full details of how and when the exception
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can be applied.
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***************************************************************************
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See http://www.FreeRTOS.org for documentation, latest information, license
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and contact details. Please ensure to read the configuration and relevant
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port sections of the online documentation.
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Also see http://www.SafeRTOS.com a version that has been certified for use
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in safety critical systems, plus commercial licensing, development and
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support options.
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***************************************************************************
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*/
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/*
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BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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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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/* Demo application includes. */
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#include "serial.h"
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/*-----------------------------------------------------------*/
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/* Location of the COM0 registers. */
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#define serCOM0 ( ( AT91PS_USART ) AT91C_BASE_US0 )
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/* Interrupt control macros. */
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#define serINTERRUPT_LEVEL ( 5 )
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#define vInterruptOn() AT91F_US_EnableIt( serCOM0, AT91C_US_TXRDY | AT91C_US_RXRDY )
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#define vInterruptOff() AT91F_US_DisableIt( serCOM0, AT91C_US_TXRDY )
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/* Misc constants. */
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#define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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#define serHANDLE ( ( xComPortHandle ) 1 )
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#define serNO_BLOCK ( ( portTickType ) 0 )
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#define serNO_TIMEGUARD ( ( unsigned portLONG ) 0 )
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#define serNO_PERIPHERAL_B_SETUP ( ( unsigned portLONG ) 0 )
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/* Queues used to hold received characters, and characters waiting to be
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transmitted. */
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static xQueueHandle xRxedChars;
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static xQueueHandle xCharsForTx;
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/*-----------------------------------------------------------*/
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/* Interrupt entry point written in the assembler file serialISR.s79. */
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extern void vSerialISREntry( void );
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/* The interrupt service routine - called from the assembly entry point. */
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__arm void vSerialISR( void );
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/*-----------------------------------------------------------*/
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/*
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* See the serial2.h header file.
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*/
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xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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{
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xComPortHandle xReturn = serHANDLE;
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extern void ( vUART_ISR )( void );
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/* Create the queues used to hold Rx and Tx characters. */
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xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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/* If the queues were created correctly then setup the serial port
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hardware. */
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if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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{
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portENTER_CRITICAL();
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{
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/* Enable the USART clock. */
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AT91F_PMC_EnablePeriphClock( AT91C_BASE_PMC, 1 << AT91C_ID_US0 );
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AT91F_PIO_CfgPeriph( AT91C_BASE_PIOA, ( ( unsigned portLONG ) AT91C_PA5_RXD0 ) | ( ( unsigned portLONG ) AT91C_PA6_TXD0 ), serNO_PERIPHERAL_B_SETUP );
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/* Set the required protocol. */
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AT91F_US_Configure( serCOM0, configCPU_CLOCK_HZ, AT91C_US_ASYNC_MODE, ulWantedBaud, serNO_TIMEGUARD );
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/* Enable Rx and Tx. */
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serCOM0->US_CR = AT91C_US_RXEN | AT91C_US_TXEN;
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/* Enable the Rx interrupts. The Tx interrupts are not enabled
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until there are characters to be transmitted. */
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AT91F_US_EnableIt( serCOM0, AT91C_US_RXRDY );
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/* Enable the interrupts in the AIC. */
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AT91F_AIC_ConfigureIt( AT91C_BASE_AIC, AT91C_ID_US0, serINTERRUPT_LEVEL, AT91C_AIC_SRCTYPE_INT_LEVEL_SENSITIVE, ( void (*)( void ) ) vSerialISREntry );
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AT91F_AIC_EnableIt( AT91C_BASE_AIC, AT91C_ID_US0 );
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}
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portEXIT_CRITICAL();
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}
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else
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{
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xReturn = ( xComPortHandle ) 0;
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}
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/* This demo file only supports a single port but we have to return
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something to comply with the standard demo header file. */
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return xReturn;
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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{
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/* The port handle is not required as this driver only supports one port. */
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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 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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void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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{
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signed portCHAR *pxNext;
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/* A couple of parameters that this port does not use. */
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( void ) usStringLength;
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( void ) pxPort;
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/* NOTE: This implementation does not handle the queue being full as no
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block time is used! */
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/* The port handle is not required as this driver only supports UART0. */
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( void ) pxPort;
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/* Send each character in the string, one at a time. */
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pxNext = ( signed portCHAR * ) pcString;
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while( *pxNext )
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{
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xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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pxNext++;
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}
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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{
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/* Place the character in the queue of characters to be transmitted. */
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if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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{
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return pdFAIL;
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}
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/* Turn on the Tx interrupt so the ISR will remove the character from the
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queue and send it. This does not need to be in a critical section as
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if the interrupt has already removed the character the next interrupt
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will simply turn off the Tx interrupt again. */
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vInterruptOn();
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return pdPASS;
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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 supported as not required by the demo application. */
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}
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/*-----------------------------------------------------------*/
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/* Serial port ISR. This can cause a context switch so is not defined as a
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standard ISR using the __irq keyword. Instead a wrapper function is defined
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within serialISR.s79 which in turn calls this function. See the port
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documentation on the FreeRTOS.org website for more information. */
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__arm void vSerialISR( void )
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{
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unsigned portLONG ulStatus;
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signed portCHAR cChar;
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portBASE_TYPE xTaskWokenByTx = pdFALSE, xTaskWokenByPost = pdFALSE;
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/* What caused the interrupt? */
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ulStatus = serCOM0->US_CSR &= serCOM0->US_IMR;
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if( ulStatus & AT91C_US_TXRDY )
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{
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/* The interrupt was caused by the THR becoming empty. Are there any
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more characters to transmit? */
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if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWokenByTx ) == pdTRUE )
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{
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/* A character was retrieved from the queue so can be sent to the
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THR now. */
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serCOM0->US_THR = cChar;
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}
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else
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{
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/* Queue empty, nothing to send so turn off the Tx interrupt. */
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vInterruptOff();
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}
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}
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if( ulStatus & AT91C_US_RXRDY )
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{
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/* The interrupt was caused by a character being received. Grab the
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character from the RHR and place it in the queue or received
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characters. */
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cChar = serCOM0->US_RHR;
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xTaskWokenByPost = xQueueSendFromISR( xRxedChars, &cChar, xTaskWokenByPost );
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}
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/* If a task was woken by either a character being received or a character
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being transmitted then we may need to switch to another task. */
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portEND_SWITCHING_ISR( ( xTaskWokenByPost || xTaskWokenByTx ) );
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/* End the interrupt in the AIC. */
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AT91C_BASE_AIC->AIC_EOICR = 0;
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}
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