2 FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not it can be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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77 * BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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79 * This file only supports UART 2
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82 /* Standard includes. */
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85 /* Scheduler includes. */
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86 #include "FreeRTOS.h"
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90 /* Demo application includes. */
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93 /* The queue used to hold received characters. */
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94 static xQueueHandle xRxedChars;
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96 /* The queue used to hold characters waiting transmission. */
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97 static xQueueHandle xCharsForTx;
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99 static volatile portSHORT sTHREEmpty;
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101 /*-----------------------------------------------------------*/
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103 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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105 portENTER_CRITICAL();
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107 /* Create the queues used by the com test task. */
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108 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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109 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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111 /* Initialize UART asynchronous mode */
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112 BGR02 = configPER_CLOCK_HZ / ulWantedBaud;
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114 SCR02 = 0x17; /* 8N1 */
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115 SMR02 = 0x0d; /* enable SOT3, Reset, normal mode */
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116 SSR02 = 0x02; /* LSB first, enable receive interrupts */
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118 PFR20_D0 = 1; /* enable UART */
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119 PFR20_D1 = 1; /* enable UART */
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121 EPFR20_D1 = 0; /* enable UART */
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123 portEXIT_CRITICAL();
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125 /* Unlike other ports, this serial code does not allow for more than one
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126 com port. We therefore don't return a pointer to a port structure and can
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127 instead just return NULL. */
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130 /*-----------------------------------------------------------*/
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132 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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134 /* Get the next character from the buffer. Return false if no characters
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135 are available, or arrive before xBlockTime expires. */
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136 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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145 /*-----------------------------------------------------------*/
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147 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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149 signed portBASE_TYPE xReturn;
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151 /* Transmit a character. */
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152 portENTER_CRITICAL();
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154 if( sTHREEmpty == pdTRUE )
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156 /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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157 there are no characters queued to be transmitted - so we can
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158 write the character directly to the shift Tx register. */
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159 sTHREEmpty = pdFALSE;
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165 /* sTHREEmpty is false, so there are still characters waiting to be
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166 transmitted. We have to queue this character so it gets
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167 transmitted in turn. */
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169 /* Return false if after the block time there is no room on the Tx
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170 queue. It is ok to block inside a critical section as each task
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171 maintains it's own critical section status. */
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172 if (xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdTRUE)
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182 if (pdPASS == xReturn)
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184 /* Turn on the Tx interrupt so the ISR will remove the character from the
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185 queue and send it. This does not need to be in a critical section as
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186 if the interrupt has already removed the character the next interrupt
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187 will simply turn off the Tx interrupt again. */
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192 portEXIT_CRITICAL();
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196 /*-----------------------------------------------------------*/
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199 * UART RX interrupt service routine.
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201 __interrupt void UART2_RxISR (void)
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203 signed portCHAR cChar;
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204 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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206 /* Get the character from the UART and post it on the queue of Rxed
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210 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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212 if( xHigherPriorityTaskWoken )
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214 /*If the post causes a task to wake force a context switch
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215 as the woken task may have a higher priority than the task we have
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217 portYIELD_FROM_ISR();
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221 /*-----------------------------------------------------------*/
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224 * UART Tx interrupt service routine.
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226 __interrupt void UART2_TxISR (void)
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228 signed portCHAR cChar;
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229 signed portBASE_TYPE xTaskWoken = pdFALSE;
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231 /* The previous character has been transmitted. See if there are any
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232 further characters waiting transmission. */
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233 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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235 /* There was another character queued - transmit it now. */
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240 /* There were no other characters to transmit. */
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241 sTHREEmpty = pdTRUE;
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243 /* Disable transmit interrupts */
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