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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 portCHAR ) 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 portSHORT sTHREEmpty;
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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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unsigned portLONG 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 portCHAR ) );
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xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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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 portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff );
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/* Setup baud rate high byte. */
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ulBaudRateCount >>= 8UL;
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U1BR1 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 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 portCHAR *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 portCHAR 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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#pragma vector=UART1RX_VECTOR
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__interrupt void vRxISR( void )
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{
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signed portCHAR 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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#pragma vector=UART1TX_VECTOR
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__interrupt void vTxISR( void )
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{
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signed portCHAR 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. */
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void vRxISR( void )
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{
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signed portCHAR 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 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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portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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}
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/*-----------------------------------------------------------*/
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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. */
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void vTxISR( void )
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{
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signed portCHAR 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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}
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#endif /* configINTERRUPT_EXAMPLE_METHOD */
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/*-----------------------------------------------------------*/
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