2 FreeRTOS V7.4.0 - 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 itcan 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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76 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR DEMO PURPOSES */
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78 #include "FreeRTOS.h"
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83 /* Constants required to setup the serial control register. */
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84 #define ser8_BIT_MODE ( ( unsigned char ) 0x40 )
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85 #define serRX_ENABLE ( ( unsigned char ) 0x10 )
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87 /* Constants to setup the timer used to generate the baud rate. */
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88 #define serCLOCK_DIV_48 ( ( unsigned char ) 0x03 )
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89 #define serUSE_PRESCALED_CLOCK ( ( unsigned char ) 0x10 )
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90 #define ser8BIT_WITH_RELOAD ( ( unsigned char ) 0x20 )
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91 #define serSMOD ( ( unsigned char ) 0x10 )
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93 static xQueueHandle xRxedChars;
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94 static xQueueHandle xCharsForTx;
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96 data static unsigned portBASE_TYPE uxTxEmpty;
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98 /*-----------------------------------------------------------*/
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100 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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102 unsigned long ulReloadValue;
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103 const portFLOAT fBaudConst = ( portFLOAT ) configCPU_CLOCK_HZ * ( portFLOAT ) 2.0;
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104 unsigned char ucOriginalSFRPage;
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106 portENTER_CRITICAL();
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108 ucOriginalSFRPage = SFRPAGE;
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111 uxTxEmpty = pdTRUE;
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113 /* Create the queues used by the com test task. */
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114 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
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115 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
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117 /* Calculate the baud rate to use timer 1. */
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118 ulReloadValue = ( unsigned long ) ( ( ( portFLOAT ) 256 - ( fBaudConst / ( portFLOAT ) ( 32 * ulWantedBaud ) ) ) + ( portFLOAT ) 0.5 );
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120 /* Set timer one for desired mode of operation. */
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122 TMOD |= ser8BIT_WITH_RELOAD;
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125 /* Set the reload and start values for the time. */
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126 TL1 = ( unsigned char ) ulReloadValue;
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127 TH1 = ( unsigned char ) ulReloadValue;
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129 /* Setup the control register for standard n, 8, 1 - variable baud rate. */
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130 SCON = ser8_BIT_MODE | serRX_ENABLE;
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132 /* Enable the serial port interrupts */
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135 /* Start the timer. */
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138 SFRPAGE = ucOriginalSFRPage;
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140 portEXIT_CRITICAL();
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142 /* Unlike some ports, this serial code does not allow for more than one
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143 com port. We therefore don't return a pointer to a port structure and can
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144 instead just return NULL. */
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147 /*-----------------------------------------------------------*/
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149 void vSerialISR( void ) interrupt 4
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152 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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154 /* 8051 port interrupt routines MUST be placed within a critical section
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155 if taskYIELD() is used within the ISR! */
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157 portENTER_CRITICAL();
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161 /* Get the character and post it on the queue of Rxed characters.
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162 If the post causes a task to wake force a context switch if the woken task
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163 has a higher priority than the task we have interrupted. */
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167 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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172 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == ( portBASE_TYPE ) pdTRUE )
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174 /* Send the next character queued for Tx. */
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179 /* Queue empty, nothing to send. */
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180 uxTxEmpty = pdTRUE;
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186 if( xHigherPriorityTaskWoken )
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191 portEXIT_CRITICAL();
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193 /*-----------------------------------------------------------*/
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195 portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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197 /* There is only one port supported. */
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200 /* Get the next character from the buffer. Return false if no characters
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201 are available, or arrive before xBlockTime expires. */
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202 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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204 return ( portBASE_TYPE ) pdTRUE;
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208 return ( portBASE_TYPE ) pdFALSE;
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211 /*-----------------------------------------------------------*/
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213 portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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215 portBASE_TYPE xReturn;
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217 /* There is only one port supported. */
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220 portENTER_CRITICAL();
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222 if( uxTxEmpty == pdTRUE )
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225 uxTxEmpty = pdFALSE;
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226 xReturn = ( portBASE_TYPE ) pdTRUE;
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230 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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232 if( xReturn == ( portBASE_TYPE ) pdFALSE )
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234 xReturn = ( portBASE_TYPE ) pdTRUE;
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238 portEXIT_CRITICAL();
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242 /*-----------------------------------------------------------*/
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244 void vSerialClose( xComPortHandle xPort )
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246 /* Not implemented in this port. */
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249 /*-----------------------------------------------------------*/
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