2 FreeRTOS V7.2.0 - 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 FOR IAR AVR PORT. */
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72 #include "FreeRTOS.h"
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77 #define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 )
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79 /* Constants for writing to UCSRB. */
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80 #define serRX_INT_ENABLE ( ( unsigned char ) 0x80 )
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81 #define serRX_ENABLE ( ( unsigned char ) 0x10 )
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82 #define serTX_ENABLE ( ( unsigned char ) 0x08 )
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83 #define serTX_INT_ENABLE ( ( unsigned char ) 0x20 )
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85 /* Constants for writing to UCSRC. */
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86 #define serUCSRC_SELECT ( ( unsigned char ) 0x80 )
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87 #define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 )
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89 static xQueueHandle xRxedChars;
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90 static xQueueHandle xCharsForTx;
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92 #define vInterruptOn() \
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94 unsigned char ucByte; \
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97 ucByte |= serTX_INT_ENABLE; \
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98 outb( UCSRB, ucByte ); \
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100 /*-----------------------------------------------------------*/
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102 #define vInterruptOff() \
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104 unsigned char ucByte; \
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107 ucByte &= ~serTX_INT_ENABLE; \
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108 outb( UCSRB, ucByte ); \
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110 /*-----------------------------------------------------------*/
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112 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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114 unsigned long ulBaudRateCounter;
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115 unsigned char ucByte;
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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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123 /* Calculate the baud rate register value from the equation in the
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125 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1;
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127 /* Set the baud rate. */
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128 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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129 outb( UBRRL, ucByte );
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131 ulBaudRateCounter >>= ( unsigned long ) 8;
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132 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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133 outb( UBRRH, ucByte );
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135 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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136 later. Also enable the Rx and Tx. */
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137 outb( UCSRB, serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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139 /* Set the data bits to 8. */
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140 outb( UCSRC, serUCSRC_SELECT | serEIGHT_DATA_BITS );
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142 portEXIT_CRITICAL();
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144 /* Unlike other ports, this serial code does not allow for more than one
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145 com port. We therefore don't return a pointer to a port structure and can
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146 instead just return NULL. */
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149 /*-----------------------------------------------------------*/
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151 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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153 /* Get the next character from the buffer. Return false if no characters
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154 are available, or arrive before xBlockTime expires. */
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155 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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164 /*-----------------------------------------------------------*/
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166 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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168 /* Return false if after the block time there is no room on the Tx queue. */
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169 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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178 /*-----------------------------------------------------------*/
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180 void vSerialClose( xComPortHandle xPort )
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182 unsigned char ucByte;
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184 /* Turn off the interrupts. We may also want to delete the queues and/or
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185 re-install the original ISR. */
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187 portENTER_CRITICAL();
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191 ucByte &= ~serRX_INT_ENABLE;
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192 outb( UCSRB, ucByte );
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194 portEXIT_CRITICAL();
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196 /*-----------------------------------------------------------*/
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198 __interrupt void SIG_UART_RECV( void )
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200 signed char ucChar, xHigherPriorityTaskWoken = pdFALSE;
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202 /* Get the character and post it on the queue of Rxed characters.
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203 If the post causes a task to wake force a context switch as the woken task
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204 may have a higher priority than the task we have interrupted. */
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207 xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken );
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209 if( xHigherPriorityTaskWoken != pdFALSE )
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214 /*-----------------------------------------------------------*/
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216 __interrupt void SIG_UART_DATA( void )
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218 signed char cChar, cTaskWoken = pdFALSE;
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220 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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222 /* Send the next character queued for Tx. */
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223 outb( UDR, cChar );
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227 /* Queue empty, nothing to send. */
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