2 FreeRTOS V8.2.0rc1 - Copyright (C) 2014 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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13 >>! NOTE: The modification to the GPL is included to allow you to !<<
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14 >>! distribute a combined work that includes FreeRTOS without being !<<
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15 >>! obliged to provide the source code for proprietary components !<<
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16 >>! outside of the FreeRTOS kernel. !<<
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18 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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19 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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20 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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21 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * Having a problem? Start by reading the FAQ "My application does *
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28 * not run, what could be wrong?". Have you defined configASSERT()? *
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30 * http://www.FreeRTOS.org/FAQHelp.html *
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32 ***************************************************************************
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34 ***************************************************************************
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36 * FreeRTOS provides completely free yet professionally developed, *
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37 * robust, strictly quality controlled, supported, and cross *
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38 * platform software that is more than just the market leader, it *
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39 * is the industry's de facto standard. *
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41 * Help yourself get started quickly while simultaneously helping *
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42 * to support the FreeRTOS project by purchasing a FreeRTOS *
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43 * tutorial book, reference manual, or both: *
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44 * http://www.FreeRTOS.org/Documentation *
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46 ***************************************************************************
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48 ***************************************************************************
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50 * Investing in training allows your team to be as productive as *
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51 * possible as early as possible, lowering your overall development *
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52 * cost, and enabling you to bring a more robust product to market *
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53 * earlier than would otherwise be possible. Richard Barry is both *
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54 * the architect and key author of FreeRTOS, and so also the world's *
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55 * leading authority on what is the world's most popular real time *
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56 * kernel for deeply embedded MCU designs. Obtaining your training *
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57 * from Richard ensures your team will gain directly from his in-depth *
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58 * product knowledge and years of usage experience. Contact Real Time *
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59 * Engineers Ltd to enquire about the FreeRTOS Masterclass, presented *
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60 * by Richard Barry: http://www.FreeRTOS.org/contact
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62 ***************************************************************************
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64 ***************************************************************************
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66 * You are receiving this top quality software for free. Please play *
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67 * fair and reciprocate by reporting any suspected issues and *
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68 * participating in the community forum: *
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69 * http://www.FreeRTOS.org/support *
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73 ***************************************************************************
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75 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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76 license and Real Time Engineers Ltd. contact details.
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78 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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79 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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80 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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82 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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83 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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85 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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86 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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87 licenses offer ticketed support, indemnification and commercial middleware.
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89 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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90 engineered and independently SIL3 certified version for use in safety and
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91 mission critical applications that require provable dependability.
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98 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR USART0.
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100 This file contains all the serial port components that must be compiled
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101 to ARM mode. The components that can be compiled to either ARM or THUMB
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102 mode are contained in serial.c.
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106 /* Standard includes. */
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107 #include <stdlib.h>
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109 /* Scheduler includes. */
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110 #include "FreeRTOS.h"
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114 /* Demo application includes. */
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115 #include "serial.h"
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116 #include "AT91R40008.h"
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119 /*-----------------------------------------------------------*/
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121 /* Constant to access the AIC. */
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122 #define serCLEAR_AIC_INTERRUPT ( ( unsigned long ) 0 )
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124 /* Constants to determine the ISR source. */
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125 #define serSOURCE_THRE ( ( unsigned char ) 0x02 )
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126 #define serSOURCE_RX_TIMEOUT ( ( unsigned char ) 0x0c )
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127 #define serSOURCE_ERROR ( ( unsigned char ) 0x06 )
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128 #define serSOURCE_RX ( ( unsigned char ) 0x04 )
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129 #define serINTERRUPT_SOURCE_MASK ( ( unsigned long ) (US_RXRDY | US_TXRDY | US_RXBRK | US_OVRE | US_FRAME | US_PARE) )
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131 /* Queues used to hold received characters, and characters waiting to be
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133 static QueueHandle_t xRxedChars;
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134 static QueueHandle_t xCharsForTx;
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136 /*-----------------------------------------------------------*/
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138 /* UART0 interrupt service routine. This can cause a context switch so MUST
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139 be declared "naked". */
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140 void vUART_ISR_Wrapper( void ) __attribute__ ((naked));
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142 /* The ISR function that actually performs the work. This must be separate
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143 from the wrapper to ensure the correct stack frame is set up. */
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144 void vUART_ISR_Handler( void ) __attribute__ ((noinline));
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146 /*-----------------------------------------------------------*/
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147 void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, QueueHandle_t *pxRxedChars, QueueHandle_t *pxCharsForTx )
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149 /* Create the queues used to hold Rx and Tx characters. */
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150 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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151 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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153 /* Pass back a reference to the queues so the serial API file can
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154 post/receive characters. */
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155 *pxRxedChars = xRxedChars;
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156 *pxCharsForTx = xCharsForTx;
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158 /*-----------------------------------------------------------*/
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160 void vUART_ISR_Wrapper( void )
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162 /* Save the context of the interrupted task. */
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163 portSAVE_CONTEXT();
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165 /* Call the handler. This must be a separate function to ensure the
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166 stack frame is correctly set up. */
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167 __asm volatile( "bl vUART_ISR_Handler" );
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169 /* Restore the context of whichever task will run next. */
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170 portRESTORE_CONTEXT();
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172 /*-----------------------------------------------------------*/
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174 void vUART_ISR_Handler( void )
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176 /* Now we can declare the local variables. These must be static. */
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178 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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179 unsigned long ulStatus;
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181 /* What caused the interrupt? */
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182 ulStatus = AT91C_BASE_US0->US_CSR & AT91C_BASE_US0->US_IMR;
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184 if (ulStatus & US_TXRDY)
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186 /* The interrupt was caused by the THR becoming empty. Are there any
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187 more characters to transmit? */
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188 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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190 /* A character was retrieved from the queue so can be sent to the
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192 AT91C_BASE_US0->US_THR = cChar;
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196 /* Queue empty, nothing to send so turn off the Tx interrupt. */
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197 AT91C_BASE_US0->US_IDR = US_TXRDY;
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201 if (ulStatus & US_RXRDY)
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203 /* The interrupt was caused by the receiver getting data. */
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204 cChar = AT91C_BASE_US0->US_RHR;
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206 xQueueSendFromISR(xRxedChars, &cChar, &xHigherPriorityTaskWoken);
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209 /* Acknowledge the interrupt at AIC level... */
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210 AT91C_BASE_AIC->AIC_EOICR = serCLEAR_AIC_INTERRUPT;
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212 /* If an event caused a task to unblock then we call "Yield from ISR" to
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213 ensure that the unblocked task is the task that executes when the interrupt
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214 completes if the unblocked task has a priority higher than the interrupted
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216 if( xHigherPriorityTaskWoken )
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218 portYIELD_FROM_ISR();
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221 /*-----------------------------------------------------------*/
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