2 FreeRTOS V7.5.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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6 ***************************************************************************
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8 * FreeRTOS provides completely free yet professionally developed, *
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9 * robust, strictly quality controlled, supported, and cross *
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10 * platform software that has become a de facto standard. *
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12 * Help yourself get started quickly and support the FreeRTOS *
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13 * project by purchasing a FreeRTOS tutorial book, reference *
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14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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18 ***************************************************************************
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20 This file is part of the FreeRTOS distribution.
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22 FreeRTOS is free software; you can redistribute it and/or modify it under
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23 the terms of the GNU General Public License (version 2) as published by the
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24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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26 >>! NOTE: The modification to the GPL is included to allow you to distribute
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27 >>! a combined work that includes FreeRTOS without being obliged to provide
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28 >>! the source code for proprietary components outside of the FreeRTOS
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31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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34 link: http://www.freertos.org/a00114.html
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38 ***************************************************************************
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40 * Having a problem? Start by reading the FAQ "My application does *
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41 * not run, what could be wrong?" *
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43 * http://www.FreeRTOS.org/FAQHelp.html *
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45 ***************************************************************************
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47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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48 license and Real Time Engineers Ltd. contact details.
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50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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56 licenses offer ticketed support, indemnification and middleware.
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58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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59 engineered and independently SIL3 certified version for use in safety and
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60 mission critical applications that require provable dependability.
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68 + The function xPortInitMinimal() has been renamed to
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69 xSerialPortInitMinimal() and the function xPortInit() has been renamed
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70 to xSerialPortInit().
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74 + Delay periods are now specified using variables and constants of
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75 portTickType rather than unsigned long.
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76 + xQueueReceiveFromISR() used in place of xQueueReceive() within the ISR.
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80 + Replaced the inb() and outb() functions with direct memory
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81 access. This allows the port to be built with the 20050414 build of
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85 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */
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89 #include <avr/interrupt.h>
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90 #include "FreeRTOS.h"
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95 #define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 )
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97 /* Constants for writing to UCSRB. */
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98 #define serRX_INT_ENABLE ( ( unsigned char ) 0x80 )
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99 #define serRX_ENABLE ( ( unsigned char ) 0x10 )
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100 #define serTX_ENABLE ( ( unsigned char ) 0x08 )
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101 #define serTX_INT_ENABLE ( ( unsigned char ) 0x20 )
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103 /* Constants for writing to UCSRC. */
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104 #define serUCSRC_SELECT ( ( unsigned char ) 0x80 )
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105 #define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 )
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107 static xQueueHandle xRxedChars;
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108 static xQueueHandle xCharsForTx;
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110 #define vInterruptOn() \
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112 unsigned char ucByte; \
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115 ucByte |= serTX_INT_ENABLE; \
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118 /*-----------------------------------------------------------*/
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120 #define vInterruptOff() \
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122 unsigned char ucInByte; \
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124 ucInByte = UCSRB; \
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125 ucInByte &= ~serTX_INT_ENABLE; \
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126 UCSRB = ucInByte; \
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128 /*-----------------------------------------------------------*/
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130 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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132 unsigned long ulBaudRateCounter;
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133 unsigned char ucByte;
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135 portENTER_CRITICAL();
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137 /* Create the queues used by the com test task. */
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138 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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139 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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141 /* Calculate the baud rate register value from the equation in the
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143 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1;
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145 /* Set the baud rate. */
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146 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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149 ulBaudRateCounter >>= ( unsigned long ) 8;
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150 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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153 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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154 later. Also enable the Rx and Tx. */
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155 UCSRB = ( serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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157 /* Set the data bits to 8. */
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158 UCSRC = ( serUCSRC_SELECT | serEIGHT_DATA_BITS );
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160 portEXIT_CRITICAL();
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162 /* Unlike other ports, this serial code does not allow for more than one
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163 com port. We therefore don't return a pointer to a port structure and can
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164 instead just return NULL. */
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167 /*-----------------------------------------------------------*/
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169 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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171 /* Only one port is supported. */
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174 /* Get the next character from the buffer. Return false if no characters
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175 are available, or arrive before xBlockTime expires. */
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176 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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185 /*-----------------------------------------------------------*/
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187 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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189 /* Only one port is supported. */
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192 /* Return false if after the block time there is no room on the Tx queue. */
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193 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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202 /*-----------------------------------------------------------*/
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204 void vSerialClose( xComPortHandle xPort )
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206 unsigned char ucByte;
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208 /* The parameter is not used. */
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211 /* Turn off the interrupts. We may also want to delete the queues and/or
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212 re-install the original ISR. */
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214 portENTER_CRITICAL();
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218 ucByte &= ~serRX_INT_ENABLE;
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221 portEXIT_CRITICAL();
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223 /*-----------------------------------------------------------*/
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225 SIGNAL( SIG_UART_RECV )
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228 signed portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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230 /* Get the character and post it on the queue of Rxed characters.
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231 If the post causes a task to wake force a context switch as the woken task
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232 may have a higher priority than the task we have interrupted. */
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235 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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237 if( xHigherPriorityTaskWoken != pdFALSE )
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242 /*-----------------------------------------------------------*/
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244 SIGNAL( SIG_UART_DATA )
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246 signed char cChar, cTaskWoken;
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248 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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250 /* Send the next character queued for Tx. */
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255 /* Queue empty, nothing to send. */
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