2 FreeRTOS V7.5.3 - Copyright (C) 2013 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS provides completely free yet professionally developed, *
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10 * robust, strictly quality controlled, supported, and cross *
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11 * platform software that has become a de facto standard. *
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13 * Help yourself get started quickly and support the FreeRTOS *
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14 * project by purchasing a FreeRTOS tutorial book, reference *
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15 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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19 ***************************************************************************
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21 This file is part of the FreeRTOS distribution.
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23 FreeRTOS is free software; you can redistribute it and/or modify it under
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24 the terms of the GNU General Public License (version 2) as published by the
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25 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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27 >>! NOTE: The modification to the GPL is included to allow you to distribute
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28 >>! a combined work that includes FreeRTOS without being obliged to provide
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29 >>! the source code for proprietary components outside of the FreeRTOS
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32 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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33 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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34 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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35 link: http://www.freertos.org/a00114.html
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39 ***************************************************************************
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41 * Having a problem? Start by reading the FAQ "My application does *
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42 * not run, what could be wrong?" *
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44 * http://www.FreeRTOS.org/FAQHelp.html *
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46 ***************************************************************************
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48 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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49 license and Real Time Engineers Ltd. contact details.
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51 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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52 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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53 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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55 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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56 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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57 licenses offer ticketed support, indemnification and middleware.
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59 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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60 engineered and independently SIL3 certified version for use in safety and
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61 mission critical applications that require provable dependability.
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69 + The function xPortInitMinimal() has been renamed to
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70 xSerialPortInitMinimal() and the function xPortInit() has been renamed
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71 to xSerialPortInit().
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75 + Delay periods are now specified using variables and constants of
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76 portTickType rather than unsigned long.
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77 + xQueueReceiveFromISR() used in place of xQueueReceive() within the ISR.
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81 + Replaced the inb() and outb() functions with direct memory
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82 access. This allows the port to be built with the 20050414 build of
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86 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */
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90 #include <avr/interrupt.h>
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91 #include "FreeRTOS.h"
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96 #define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 )
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98 /* Constants for writing to UCSRB. */
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99 #define serRX_INT_ENABLE ( ( unsigned char ) 0x80 )
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100 #define serRX_ENABLE ( ( unsigned char ) 0x10 )
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101 #define serTX_ENABLE ( ( unsigned char ) 0x08 )
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102 #define serTX_INT_ENABLE ( ( unsigned char ) 0x20 )
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104 /* Constants for writing to UCSRC. */
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105 #define serUCSRC_SELECT ( ( unsigned char ) 0x80 )
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106 #define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 )
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108 static xQueueHandle xRxedChars;
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109 static xQueueHandle xCharsForTx;
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111 #define vInterruptOn() \
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113 unsigned char ucByte; \
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116 ucByte |= serTX_INT_ENABLE; \
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119 /*-----------------------------------------------------------*/
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121 #define vInterruptOff() \
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123 unsigned char ucInByte; \
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125 ucInByte = UCSRB; \
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126 ucInByte &= ~serTX_INT_ENABLE; \
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127 UCSRB = ucInByte; \
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129 /*-----------------------------------------------------------*/
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131 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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133 unsigned long ulBaudRateCounter;
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134 unsigned char ucByte;
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136 portENTER_CRITICAL();
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138 /* Create the queues used by the com test task. */
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139 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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140 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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142 /* Calculate the baud rate register value from the equation in the
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144 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1;
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146 /* Set the baud rate. */
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147 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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150 ulBaudRateCounter >>= ( unsigned long ) 8;
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151 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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154 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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155 later. Also enable the Rx and Tx. */
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156 UCSRB = ( serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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158 /* Set the data bits to 8. */
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159 UCSRC = ( serUCSRC_SELECT | serEIGHT_DATA_BITS );
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161 portEXIT_CRITICAL();
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163 /* Unlike other ports, this serial code does not allow for more than one
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164 com port. We therefore don't return a pointer to a port structure and can
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165 instead just return NULL. */
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168 /*-----------------------------------------------------------*/
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170 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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172 /* Only one port is supported. */
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175 /* Get the next character from the buffer. Return false if no characters
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176 are available, or arrive before xBlockTime expires. */
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177 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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186 /*-----------------------------------------------------------*/
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188 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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190 /* Only one port is supported. */
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193 /* Return false if after the block time there is no room on the Tx queue. */
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194 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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203 /*-----------------------------------------------------------*/
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205 void vSerialClose( xComPortHandle xPort )
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207 unsigned char ucByte;
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209 /* The parameter is not used. */
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212 /* Turn off the interrupts. We may also want to delete the queues and/or
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213 re-install the original ISR. */
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215 portENTER_CRITICAL();
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219 ucByte &= ~serRX_INT_ENABLE;
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222 portEXIT_CRITICAL();
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224 /*-----------------------------------------------------------*/
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226 SIGNAL( SIG_UART_RECV )
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229 signed portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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231 /* Get the character and post it on the queue of Rxed characters.
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232 If the post causes a task to wake force a context switch as the woken task
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233 may have a higher priority than the task we have interrupted. */
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236 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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238 if( xHigherPriorityTaskWoken != pdFALSE )
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243 /*-----------------------------------------------------------*/
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245 SIGNAL( SIG_UART_DATA )
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247 signed char cChar, cTaskWoken;
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249 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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251 /* Send the next character queued for Tx. */
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256 /* Queue empty, nothing to send. */
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