2 FreeRTOS V7.2.0 - Copyright (C) 2012 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 >>>NOTE<<< The modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 ***************************************************************************
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46 * Having a problem? Start by reading the FAQ "My application does *
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47 * not run, what could be wrong? *
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49 * http://www.FreeRTOS.org/FAQHelp.html *
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51 ***************************************************************************
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54 http://www.FreeRTOS.org - Documentation, training, latest information,
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55 license and contact details.
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57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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58 including FreeRTOS+Trace - an indispensable productivity tool.
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60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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61 the code with commercial support, indemnification, and middleware, under
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62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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63 provide a safety engineered and independently SIL3 certified version under
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64 the SafeRTOS brand: http://www.SafeRTOS.com.
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69 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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71 This file contains all the serial port components that must be compiled
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72 to ARM mode. The components that can be compiled to either ARM or THUMB
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73 mode are contained in serial.c.
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77 /* Standard includes. */
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80 /* Scheduler includes. */
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81 #include "FreeRTOS.h"
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85 /* Demo application includes. */
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88 /*-----------------------------------------------------------*/
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90 /* Constant to access the VIC. */
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91 #define serCLEAR_VIC_INTERRUPT ( ( unsigned long ) 0 )
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93 /* Constants to determine the ISR source. */
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94 #define serSOURCE_THRE ( ( unsigned char ) 0x02 )
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95 #define serSOURCE_RX_TIMEOUT ( ( unsigned char ) 0x0c )
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96 #define serSOURCE_ERROR ( ( unsigned char ) 0x06 )
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97 #define serSOURCE_RX ( ( unsigned char ) 0x04 )
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98 #define serINTERRUPT_SOURCE_MASK ( ( unsigned char ) 0x0f )
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100 /* Queues used to hold received characters, and characters waiting to be
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102 static xQueueHandle xRxedChars;
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103 static xQueueHandle xCharsForTx;
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104 static volatile long lTHREEmpty;
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106 /*-----------------------------------------------------------*/
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109 * The queues are created in serialISR.c as they are used from the ISR.
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110 * Obtain references to the queues and THRE Empty flag.
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112 void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag );
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114 /* UART0 interrupt service routine entry point. */
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115 void vUART_ISR_Wrapper( void ) __attribute__ ((naked));
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117 /* UART0 interrupt service routine handler. */
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118 void vUART_ISR_Handler( void ) __attribute__ ((noinline));
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120 /*-----------------------------------------------------------*/
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121 void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars,
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122 xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag )
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124 /* Create the queues used to hold Rx and Tx characters. */
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125 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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126 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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128 /* Pass back a reference to the queues so the serial API file can
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129 post/receive characters. */
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130 *pxRxedChars = xRxedChars;
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131 *pxCharsForTx = xCharsForTx;
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133 /* Initialise the THRE empty flag - and pass back a reference. */
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134 lTHREEmpty = ( long ) pdTRUE;
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135 *pplTHREEmptyFlag = &lTHREEmpty;
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137 /*-----------------------------------------------------------*/
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139 void vUART_ISR_Wrapper( void )
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141 /* Save the context of the interrupted task. */
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142 portSAVE_CONTEXT();
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144 /* Call the handler. This must be a separate function from the wrapper
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145 to ensure the correct stack frame is set up. */
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146 __asm volatile ("bl vUART_ISR_Handler");
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148 /* Restore the context of whichever task is going to run next. */
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149 portRESTORE_CONTEXT();
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151 /*-----------------------------------------------------------*/
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153 void vUART_ISR_Handler( void )
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156 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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158 /* What caused the interrupt? */
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159 switch( UART0_IIR & serINTERRUPT_SOURCE_MASK )
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161 case serSOURCE_ERROR : /* Not handling this, but clear the interrupt. */
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165 case serSOURCE_THRE : /* The THRE is empty. If there is another
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166 character in the Tx queue, send it now. */
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167 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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173 /* There are no further characters
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174 queued to send so we can indicate
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175 that the THRE is available. */
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176 lTHREEmpty = pdTRUE;
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180 case serSOURCE_RX_TIMEOUT :
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181 case serSOURCE_RX : /* A character was received. Place it in
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182 the queue of received characters. */
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184 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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187 default : /* There is nothing to do, leave the ISR. */
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191 if( xHigherPriorityTaskWoken )
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193 portYIELD_FROM_ISR();
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196 /* Clear the ISR in the VIC. */
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197 VICVectAddr = serCLEAR_VIC_INTERRUPT;
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