2 FreeRTOS V7.3.0 - Copyright (C) 2012 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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32 >>>NOTE<<< The modification to the GPL is included to allow you to
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33 distribute a combined work that includes FreeRTOS without being obliged to
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34 provide the source code for proprietary components outside of the FreeRTOS
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35 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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36 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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37 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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38 more details. You should have received a copy of the GNU General Public
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39 License and the FreeRTOS license exception along with FreeRTOS; if not it
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40 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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41 by writing to Richard Barry, contact details for whom are available on the
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46 ***************************************************************************
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48 * Having a problem? Start by reading the FAQ "My application does *
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49 * not run, what could be wrong?" *
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51 * http://www.FreeRTOS.org/FAQHelp.html *
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53 ***************************************************************************
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56 http://www.FreeRTOS.org - Documentation, training, latest versions, license
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57 and contact details.
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59 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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60 including FreeRTOS+Trace - an indispensable productivity tool.
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62 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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63 the code with commercial support, indemnification, and middleware, under
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64 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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65 provide a safety engineered and independently SIL3 certified version under
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66 the SafeRTOS brand: http://www.SafeRTOS.com.
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70 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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72 * This file only supports UART 1
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75 /* Standard includes. */
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79 /* Scheduler includes. */
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80 #include "FreeRTOS.h"
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84 /* Demo application includes. */
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87 /* Constants required to setup the hardware. */
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88 #define serTX_AND_RX ( ( unsigned char ) 0x03 )
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90 /* Misc. constants. */
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91 #define serNO_BLOCK ( ( portTickType ) 0 )
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93 /* Enable the UART Tx interrupt. */
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94 #define vInterruptOn() IFG2 |= UTXIFG1
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96 /* The queue used to hold received characters. */
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97 static xQueueHandle xRxedChars;
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99 /* The queue used to hold characters waiting transmission. */
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100 static xQueueHandle xCharsForTx;
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102 static volatile short sTHREEmpty;
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104 /* Interrupt service routines. */
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105 interrupt (UART1RX_VECTOR) wakeup vRxISR( void );
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106 interrupt (UART1TX_VECTOR) wakeup vTxISR( void );
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108 /*-----------------------------------------------------------*/
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110 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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112 unsigned long ulBaudRateCount;
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114 /* Initialise the hardware. */
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116 /* Generate the baud rate constants for the wanted baud rate. */
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117 ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud;
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119 portENTER_CRITICAL();
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121 /* Create the queues used by the com test task. */
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122 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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123 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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128 /* Set pin function. */
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129 P4SEL |= serTX_AND_RX;
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131 /* All other bits remain at zero for n, 8, 1 interrupt driven operation.
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133 U1CTL |= CHAR + LISTEN;
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136 /* Setup baud rate low byte. */
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137 U1BR0 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );
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139 /* Setup baud rate high byte. */
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140 ulBaudRateCount >>= 8UL;
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141 U1BR1 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );
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143 /* Enable ports. */
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144 ME2 |= UTXE1 + URXE1;
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149 /* Nothing in the buffer yet. */
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150 sTHREEmpty = pdTRUE;
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152 /* Enable interrupts. */
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153 IE2 |= URXIE1 + UTXIE1;
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155 portEXIT_CRITICAL();
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157 /* Unlike other ports, this serial code does not allow for more than one
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158 com port. We therefore don't return a pointer to a port structure and can
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159 instead just return NULL. */
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162 /*-----------------------------------------------------------*/
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164 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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166 /* Get the next character from the buffer. Return false if no characters
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167 are available, or arrive before xBlockTime expires. */
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168 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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177 /*-----------------------------------------------------------*/
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179 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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181 signed portBASE_TYPE xReturn;
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183 /* Transmit a character. */
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185 portENTER_CRITICAL();
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187 if( sTHREEmpty == pdTRUE )
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189 /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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190 there are no characters queued to be transmitted - so we can
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191 write the character directly to the shift Tx register. */
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192 sTHREEmpty = pdFALSE;
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193 U1TXBUF = cOutChar;
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198 /* sTHREEmpty is false, so there are still characters waiting to be
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199 transmitted. We have to queue this character so it gets
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200 transmitted in turn. */
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202 /* Return false if after the block time there is no room on the Tx
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203 queue. It is ok to block inside a critical section as each task
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204 maintains it's own critical section status. */
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205 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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207 /* Depending on queue sizing and task prioritisation: While we
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208 were blocked waiting to post on the queue interrupts were not
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209 disabled. It is possible that the serial ISR has emptied the
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210 Tx queue, in which case we need to start the Tx off again
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211 writing directly to the Tx register. */
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212 if( ( sTHREEmpty == pdTRUE ) && ( xReturn == pdPASS ) )
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214 /* Get back the character we just posted. */
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215 xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
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216 sTHREEmpty = pdFALSE;
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217 U1TXBUF = cOutChar;
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221 portEXIT_CRITICAL();
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225 /*-----------------------------------------------------------*/
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228 * UART RX interrupt service routine.
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230 interrupt (UART1RX_VECTOR) wakeup vRxISR( void )
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233 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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235 /* Get the character from the UART and post it on the queue of Rxed
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239 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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241 if( xHigherPriorityTaskWoken )
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243 /*If the post causes a task to wake force a context switch
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244 as the woken task may have a higher priority than the task we have
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249 /*-----------------------------------------------------------*/
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252 * UART Tx interrupt service routine.
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254 interrupt (UART1TX_VECTOR) wakeup vTxISR( void )
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257 portBASE_TYPE xTaskWoken = pdFALSE;
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259 /* The previous character has been transmitted. See if there are any
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260 further characters waiting transmission. */
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262 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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264 /* There was another character queued - transmit it now. */
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269 /* There were no other characters to transmit. */
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270 sTHREEmpty = pdTRUE;
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