2 FreeRTOS V7.5.0 - 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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66 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR IAR AVR PORT. */
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70 #include "FreeRTOS.h"
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75 #define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 )
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77 /* Constants for writing to UCSRB. */
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78 #define serRX_INT_ENABLE ( ( unsigned char ) 0x80 )
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79 #define serRX_ENABLE ( ( unsigned char ) 0x10 )
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80 #define serTX_ENABLE ( ( unsigned char ) 0x08 )
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81 #define serTX_INT_ENABLE ( ( unsigned char ) 0x20 )
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83 /* Constants for writing to UCSRC. */
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84 #define serUCSRC_SELECT ( ( unsigned char ) 0x80 )
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85 #define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 )
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87 static xQueueHandle xRxedChars;
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88 static xQueueHandle xCharsForTx;
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90 #define vInterruptOn() \
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92 unsigned char ucByte; \
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95 ucByte |= serTX_INT_ENABLE; \
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96 outb( UCSRB, ucByte ); \
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98 /*-----------------------------------------------------------*/
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100 #define vInterruptOff() \
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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 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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112 unsigned long ulBaudRateCounter;
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113 unsigned char ucByte;
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115 portENTER_CRITICAL();
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117 /* Create the queues used by the com test task. */
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118 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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119 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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121 /* Calculate the baud rate register value from the equation in the
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123 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1;
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125 /* Set the baud rate. */
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126 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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127 outb( UBRRL, ucByte );
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129 ulBaudRateCounter >>= ( unsigned long ) 8;
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130 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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131 outb( UBRRH, ucByte );
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133 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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134 later. Also enable the Rx and Tx. */
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135 outb( UCSRB, serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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137 /* Set the data bits to 8. */
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138 outb( UCSRC, serUCSRC_SELECT | serEIGHT_DATA_BITS );
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140 portEXIT_CRITICAL();
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142 /* Unlike other ports, this serial code does not allow for more than one
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143 com port. We therefore don't return a pointer to a port structure and can
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144 instead just return NULL. */
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147 /*-----------------------------------------------------------*/
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149 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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151 /* Get the next character from the buffer. Return false if no characters
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152 are available, or arrive before xBlockTime expires. */
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153 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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162 /*-----------------------------------------------------------*/
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164 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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166 /* Return false if after the block time there is no room on the Tx queue. */
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167 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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176 /*-----------------------------------------------------------*/
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178 void vSerialClose( xComPortHandle xPort )
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180 unsigned char ucByte;
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182 /* Turn off the interrupts. We may also want to delete the queues and/or
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183 re-install the original ISR. */
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185 portENTER_CRITICAL();
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189 ucByte &= ~serRX_INT_ENABLE;
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190 outb( UCSRB, ucByte );
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192 portEXIT_CRITICAL();
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194 /*-----------------------------------------------------------*/
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196 __interrupt void SIG_UART_RECV( void )
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198 signed char ucChar, xHigherPriorityTaskWoken = pdFALSE;
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200 /* Get the character and post it on the queue of Rxed characters.
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201 If the post causes a task to wake force a context switch as the woken task
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202 may have a higher priority than the task we have interrupted. */
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205 xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken );
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207 if( xHigherPriorityTaskWoken != pdFALSE )
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212 /*-----------------------------------------------------------*/
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214 __interrupt void SIG_UART_DATA( void )
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216 signed char cChar, cTaskWoken = pdFALSE;
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218 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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220 /* Send the next character queued for Tx. */
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221 outb( UDR, cChar );
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225 /* Queue empty, nothing to send. */
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