2 FreeRTOS V7.0.1 - Copyright (C) 2011 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 http://www.FreeRTOS.org - Documentation, latest information, license and
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47 http://www.SafeRTOS.com - A version that is certified for use in safety
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50 http://www.OpenRTOS.com - Commercial support, development, porting,
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51 licensing and training services.
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57 + The function xPortInitMinimal() has been renamed to
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58 xSerialPortInitMinimal() and the function xPortInit() has been renamed
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59 to xSerialPortInit().
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63 + Delay periods are now specified using variables and constants of
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64 portTickType rather than unsigned long.
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65 + xQueueReceiveFromISR() used in place of xQueueReceive() within the ISR.
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69 + Replaced the inb() and outb() functions with direct memory
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70 access. This allows the port to be built with the 20050414 build of
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74 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */
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78 #include <avr/interrupt.h>
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79 #include "FreeRTOS.h"
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84 #define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 )
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86 /* Constants for writing to UCSRB. */
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87 #define serRX_INT_ENABLE ( ( unsigned char ) 0x80 )
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88 #define serRX_ENABLE ( ( unsigned char ) 0x10 )
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89 #define serTX_ENABLE ( ( unsigned char ) 0x08 )
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90 #define serTX_INT_ENABLE ( ( unsigned char ) 0x20 )
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92 /* Constants for writing to UCSRC. */
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93 #define serUCSRC_SELECT ( ( unsigned char ) 0x80 )
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94 #define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 )
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96 static xQueueHandle xRxedChars;
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97 static xQueueHandle xCharsForTx;
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99 #define vInterruptOn() \
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101 unsigned char ucByte; \
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104 ucByte |= serTX_INT_ENABLE; \
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107 /*-----------------------------------------------------------*/
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109 #define vInterruptOff() \
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111 unsigned char ucInByte; \
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113 ucInByte = UCSRB; \
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114 ucInByte &= ~serTX_INT_ENABLE; \
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115 UCSRB = ucInByte; \
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117 /*-----------------------------------------------------------*/
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119 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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121 unsigned long ulBaudRateCounter;
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122 unsigned char ucByte;
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124 portENTER_CRITICAL();
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126 /* Create the queues used by the com test task. */
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127 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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128 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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130 /* Calculate the baud rate register value from the equation in the
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132 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1;
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134 /* Set the baud rate. */
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135 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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138 ulBaudRateCounter >>= ( unsigned long ) 8;
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139 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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142 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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143 later. Also enable the Rx and Tx. */
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144 UCSRB = ( serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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146 /* Set the data bits to 8. */
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147 UCSRC = ( serUCSRC_SELECT | serEIGHT_DATA_BITS );
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149 portEXIT_CRITICAL();
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151 /* Unlike other ports, this serial code does not allow for more than one
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152 com port. We therefore don't return a pointer to a port structure and can
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153 instead just return NULL. */
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156 /*-----------------------------------------------------------*/
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158 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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160 /* Only one port is supported. */
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163 /* Get the next character from the buffer. Return false if no characters
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164 are available, or arrive before xBlockTime expires. */
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165 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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174 /*-----------------------------------------------------------*/
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176 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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178 /* Only one port is supported. */
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181 /* Return false if after the block time there is no room on the Tx queue. */
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182 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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191 /*-----------------------------------------------------------*/
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193 void vSerialClose( xComPortHandle xPort )
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195 unsigned char ucByte;
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197 /* The parameter is not used. */
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200 /* Turn off the interrupts. We may also want to delete the queues and/or
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201 re-install the original ISR. */
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203 portENTER_CRITICAL();
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207 ucByte &= ~serRX_INT_ENABLE;
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210 portEXIT_CRITICAL();
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212 /*-----------------------------------------------------------*/
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214 SIGNAL( SIG_UART_RECV )
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217 signed portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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219 /* Get the character and post it on the queue of Rxed characters.
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220 If the post causes a task to wake force a context switch as the woken task
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221 may have a higher priority than the task we have interrupted. */
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224 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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226 if( xHigherPriorityTaskWoken != pdFALSE )
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231 /*-----------------------------------------------------------*/
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233 SIGNAL( SIG_UART_DATA )
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235 signed char cChar, cTaskWoken;
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237 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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239 /* Send the next character queued for Tx. */
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244 /* Queue empty, nothing to send. */
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