2 FreeRTOS V7.5.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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6 ***************************************************************************
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8 * FreeRTOS provides completely free yet professionally developed, *
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9 * robust, strictly quality controlled, supported, and cross *
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10 * platform software that has become a de facto standard. *
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12 * Help yourself get started quickly and support the FreeRTOS *
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13 * project by purchasing a FreeRTOS tutorial book, reference *
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14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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18 ***************************************************************************
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20 This file is part of the FreeRTOS distribution.
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22 FreeRTOS is free software; you can redistribute it and/or modify it under
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23 the terms of the GNU General Public License (version 2) as published by the
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24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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26 >>! NOTE: The modification to the GPL is included to allow you to distribute
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27 >>! a combined work that includes FreeRTOS without being obliged to provide
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28 >>! the source code for proprietary components outside of the FreeRTOS
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31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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34 link: http://www.freertos.org/a00114.html
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38 ***************************************************************************
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40 * Having a problem? Start by reading the FAQ "My application does *
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41 * not run, what could be wrong?" *
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43 * http://www.FreeRTOS.org/FAQHelp.html *
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45 ***************************************************************************
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47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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48 license and Real Time Engineers Ltd. contact details.
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50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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56 licenses offer ticketed support, indemnification and middleware.
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58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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59 engineered and independently SIL3 certified version for use in safety and
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60 mission critical applications that require provable dependability.
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67 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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69 This file contains all the serial port components that must be compiled
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70 to ARM mode. The components that can be compiled to either ARM or THUMB
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71 mode are contained in serial.c.
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75 /* Standard includes. */
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78 /* Scheduler includes. */
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79 #include "FreeRTOS.h"
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83 /* Demo application includes. */
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86 /*-----------------------------------------------------------*/
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88 /* Constant to access the VIC. */
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89 #define serCLEAR_VIC_INTERRUPT ( ( unsigned long ) 0 )
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91 /* Constants to determine the ISR source. */
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92 #define serSOURCE_THRE ( ( unsigned char ) 0x02 )
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93 #define serSOURCE_RX_TIMEOUT ( ( unsigned char ) 0x0c )
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94 #define serSOURCE_ERROR ( ( unsigned char ) 0x06 )
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95 #define serSOURCE_RX ( ( unsigned char ) 0x04 )
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96 #define serINTERRUPT_SOURCE_MASK ( ( unsigned char ) 0x0f )
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98 /* Queues used to hold received characters, and characters waiting to be
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100 static xQueueHandle xRxedChars;
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101 static xQueueHandle xCharsForTx;
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102 static volatile long lTHREEmpty;
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104 /*-----------------------------------------------------------*/
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107 * The queues are created in serialISR.c as they are used from the ISR.
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108 * Obtain references to the queues and THRE Empty flag.
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110 void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag );
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112 /* UART0 interrupt service routine entry point. */
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113 void vUART_ISR_Wrapper( void ) __attribute__ ((naked));
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115 /* UART0 interrupt service routine handler. */
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116 void vUART_ISR_Handler( void ) __attribute__ ((noinline));
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118 /*-----------------------------------------------------------*/
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119 void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars,
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120 xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag )
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122 /* Create the queues used to hold Rx and Tx characters. */
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123 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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124 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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126 /* Pass back a reference to the queues so the serial API file can
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127 post/receive characters. */
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128 *pxRxedChars = xRxedChars;
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129 *pxCharsForTx = xCharsForTx;
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131 /* Initialise the THRE empty flag - and pass back a reference. */
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132 lTHREEmpty = ( long ) pdTRUE;
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133 *pplTHREEmptyFlag = &lTHREEmpty;
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135 /*-----------------------------------------------------------*/
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137 void vUART_ISR_Wrapper( void )
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139 /* Save the context of the interrupted task. */
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140 portSAVE_CONTEXT();
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142 /* Call the handler. This must be a separate function from the wrapper
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143 to ensure the correct stack frame is set up. */
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144 __asm volatile ("bl vUART_ISR_Handler");
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146 /* Restore the context of whichever task is going to run next. */
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147 portRESTORE_CONTEXT();
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149 /*-----------------------------------------------------------*/
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151 void vUART_ISR_Handler( void )
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154 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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156 /* What caused the interrupt? */
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157 switch( UART0_IIR & serINTERRUPT_SOURCE_MASK )
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159 case serSOURCE_ERROR : /* Not handling this, but clear the interrupt. */
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163 case serSOURCE_THRE : /* The THRE is empty. If there is another
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164 character in the Tx queue, send it now. */
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165 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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171 /* There are no further characters
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172 queued to send so we can indicate
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173 that the THRE is available. */
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174 lTHREEmpty = pdTRUE;
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178 case serSOURCE_RX_TIMEOUT :
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179 case serSOURCE_RX : /* A character was received. Place it in
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180 the queue of received characters. */
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182 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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185 default : /* There is nothing to do, leave the ISR. */
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189 if( xHigherPriorityTaskWoken )
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191 portYIELD_FROM_ISR();
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194 /* Clear the ISR in the VIC. */
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195 VICVectAddr = serCLEAR_VIC_INTERRUPT;
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