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 IAR AVR PORT. */
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80 #include "FreeRTOS.h"
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85 #define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 )
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87 /* Constants for writing to UCSRB. */
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88 #define serRX_INT_ENABLE ( ( unsigned char ) 0x80 )
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89 #define serRX_ENABLE ( ( unsigned char ) 0x10 )
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90 #define serTX_ENABLE ( ( unsigned char ) 0x08 )
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91 #define serTX_INT_ENABLE ( ( unsigned char ) 0x20 )
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93 /* Constants for writing to UCSRC. */
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94 #define serUCSRC_SELECT ( ( unsigned char ) 0x80 )
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95 #define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 )
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97 static xQueueHandle xRxedChars;
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98 static xQueueHandle xCharsForTx;
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100 #define vInterruptOn() \
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102 unsigned char ucByte; \
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105 ucByte |= serTX_INT_ENABLE; \
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106 outb( UCSRB, ucByte ); \
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108 /*-----------------------------------------------------------*/
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110 #define vInterruptOff() \
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112 unsigned char ucByte; \
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115 ucByte &= ~serTX_INT_ENABLE; \
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116 outb( UCSRB, ucByte ); \
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118 /*-----------------------------------------------------------*/
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120 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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122 unsigned long ulBaudRateCounter;
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123 unsigned char ucByte;
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125 portENTER_CRITICAL();
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127 /* Create the queues used by the com test task. */
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128 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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129 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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131 /* Calculate the baud rate register value from the equation in the
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133 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1;
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135 /* Set the baud rate. */
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136 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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137 outb( UBRRL, ucByte );
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139 ulBaudRateCounter >>= ( unsigned long ) 8;
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140 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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141 outb( UBRRH, ucByte );
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143 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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144 later. Also enable the Rx and Tx. */
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145 outb( UCSRB, serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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147 /* Set the data bits to 8. */
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148 outb( UCSRC, serUCSRC_SELECT | serEIGHT_DATA_BITS );
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150 portEXIT_CRITICAL();
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152 /* Unlike other ports, this serial code does not allow for more than one
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153 com port. We therefore don't return a pointer to a port structure and can
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154 instead just return NULL. */
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157 /*-----------------------------------------------------------*/
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159 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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161 /* Get the next character from the buffer. Return false if no characters
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162 are available, or arrive before xBlockTime expires. */
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163 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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172 /*-----------------------------------------------------------*/
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174 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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176 /* Return false if after the block time there is no room on the Tx queue. */
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177 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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186 /*-----------------------------------------------------------*/
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188 void vSerialClose( xComPortHandle xPort )
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190 unsigned char ucByte;
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192 /* Turn off the interrupts. We may also want to delete the queues and/or
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193 re-install the original ISR. */
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195 portENTER_CRITICAL();
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199 ucByte &= ~serRX_INT_ENABLE;
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200 outb( UCSRB, ucByte );
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202 portEXIT_CRITICAL();
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204 /*-----------------------------------------------------------*/
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206 __interrupt void SIG_UART_RECV( void )
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208 signed char ucChar, xHigherPriorityTaskWoken = pdFALSE;
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210 /* Get the character and post it on the queue of Rxed characters.
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211 If the post causes a task to wake force a context switch as the woken task
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212 may have a higher priority than the task we have interrupted. */
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215 xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken );
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217 if( xHigherPriorityTaskWoken != pdFALSE )
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222 /*-----------------------------------------------------------*/
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224 __interrupt void SIG_UART_DATA( void )
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226 signed char cChar, cTaskWoken = pdFALSE;
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228 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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230 /* Send the next character queued for Tx. */
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231 outb( UDR, cChar );
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235 /* Queue empty, nothing to send. */
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