2 FreeRTOS V7.1.1 - 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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68 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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70 * This file only supports UART 1
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73 /* Standard includes. */
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77 /* Scheduler includes. */
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78 #include "FreeRTOS.h"
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82 /* Demo application includes. */
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85 /* Constants required to setup the hardware. */
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86 #define serTX_AND_RX ( ( unsigned char ) 0x03 )
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88 /* Misc. constants. */
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89 #define serNO_BLOCK ( ( portTickType ) 0 )
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91 /* Enable the UART Tx interrupt. */
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92 #define vInterruptOn() IFG2 |= UTXIFG1
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94 /* The queue used to hold received characters. */
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95 static xQueueHandle xRxedChars;
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97 /* The queue used to hold characters waiting transmission. */
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98 static xQueueHandle xCharsForTx;
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100 static volatile short sTHREEmpty;
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102 /* Interrupt service routines. */
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103 interrupt (UART1RX_VECTOR) wakeup vRxISR( void );
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104 interrupt (UART1TX_VECTOR) wakeup vTxISR( void );
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106 /*-----------------------------------------------------------*/
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108 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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110 unsigned long ulBaudRateCount;
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112 /* Initialise the hardware. */
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114 /* Generate the baud rate constants for the wanted baud rate. */
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115 ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud;
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117 portENTER_CRITICAL();
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119 /* Create the queues used by the com test task. */
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120 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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121 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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126 /* Set pin function. */
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127 P4SEL |= serTX_AND_RX;
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129 /* All other bits remain at zero for n, 8, 1 interrupt driven operation.
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131 U1CTL |= CHAR + LISTEN;
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134 /* Setup baud rate low byte. */
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135 U1BR0 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );
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137 /* Setup baud rate high byte. */
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138 ulBaudRateCount >>= 8UL;
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139 U1BR1 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );
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141 /* Enable ports. */
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142 ME2 |= UTXE1 + URXE1;
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147 /* Nothing in the buffer yet. */
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148 sTHREEmpty = pdTRUE;
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150 /* Enable interrupts. */
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151 IE2 |= URXIE1 + UTXIE1;
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153 portEXIT_CRITICAL();
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155 /* Unlike other ports, this serial code does not allow for more than one
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156 com port. We therefore don't return a pointer to a port structure and can
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157 instead just return NULL. */
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160 /*-----------------------------------------------------------*/
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162 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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164 /* Get the next character from the buffer. Return false if no characters
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165 are available, or arrive before xBlockTime expires. */
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166 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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175 /*-----------------------------------------------------------*/
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177 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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179 signed portBASE_TYPE xReturn;
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181 /* Transmit a character. */
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183 portENTER_CRITICAL();
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185 if( sTHREEmpty == pdTRUE )
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187 /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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188 there are no characters queued to be transmitted - so we can
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189 write the character directly to the shift Tx register. */
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190 sTHREEmpty = pdFALSE;
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191 U1TXBUF = cOutChar;
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196 /* sTHREEmpty is false, so there are still characters waiting to be
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197 transmitted. We have to queue this character so it gets
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198 transmitted in turn. */
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200 /* Return false if after the block time there is no room on the Tx
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201 queue. It is ok to block inside a critical section as each task
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202 maintains it's own critical section status. */
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203 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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205 /* Depending on queue sizing and task prioritisation: While we
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206 were blocked waiting to post on the queue interrupts were not
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207 disabled. It is possible that the serial ISR has emptied the
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208 Tx queue, in which case we need to start the Tx off again
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209 writing directly to the Tx register. */
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210 if( ( sTHREEmpty == pdTRUE ) && ( xReturn == pdPASS ) )
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212 /* Get back the character we just posted. */
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213 xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
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214 sTHREEmpty = pdFALSE;
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215 U1TXBUF = cOutChar;
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219 portEXIT_CRITICAL();
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223 /*-----------------------------------------------------------*/
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226 * UART RX interrupt service routine.
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228 interrupt (UART1RX_VECTOR) wakeup vRxISR( void )
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231 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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233 /* Get the character from the UART and post it on the queue of Rxed
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237 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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239 if( xHigherPriorityTaskWoken )
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241 /*If the post causes a task to wake force a context switch
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242 as the woken task may have a higher priority than the task we have
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247 /*-----------------------------------------------------------*/
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250 * UART Tx interrupt service routine.
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252 interrupt (UART1TX_VECTOR) wakeup vTxISR( void )
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255 portBASE_TYPE xTaskWoken = pdFALSE;
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257 /* The previous character has been transmitted. See if there are any
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258 further characters waiting transmission. */
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260 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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262 /* There was another character queued - transmit it now. */
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267 /* There were no other characters to transmit. */
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268 sTHREEmpty = pdTRUE;
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