2 FreeRTOS.org V4.7.0 - Copyright (C) 2003-2007 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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31 Also see http://www.SafeRTOS.com a version that has been certified for use
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32 in safety critical systems, plus commercial licensing, development and
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34 ***************************************************************************
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38 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR IAR AVR PORT. */
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42 #include "FreeRTOS.h"
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47 #define serBAUD_DIV_CONSTANT ( ( unsigned portLONG ) 16 )
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49 /* Constants for writing to UCSRB. */
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50 #define serRX_INT_ENABLE ( ( unsigned portCHAR ) 0x80 )
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51 #define serRX_ENABLE ( ( unsigned portCHAR ) 0x10 )
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52 #define serTX_ENABLE ( ( unsigned portCHAR ) 0x08 )
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53 #define serTX_INT_ENABLE ( ( unsigned portCHAR ) 0x20 )
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55 /* Constants for writing to UCSRC. */
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56 #define serUCSRC_SELECT ( ( unsigned portCHAR ) 0x80 )
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57 #define serEIGHT_DATA_BITS ( ( unsigned portCHAR ) 0x06 )
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59 static xQueueHandle xRxedChars;
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60 static xQueueHandle xCharsForTx;
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62 #define vInterruptOn() \
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64 unsigned portCHAR ucByte; \
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67 ucByte |= serTX_INT_ENABLE; \
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68 outb( UCSRB, ucByte ); \
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70 /*-----------------------------------------------------------*/
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72 #define vInterruptOff() \
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74 unsigned portCHAR ucByte; \
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77 ucByte &= ~serTX_INT_ENABLE; \
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78 outb( UCSRB, ucByte ); \
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80 /*-----------------------------------------------------------*/
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82 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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84 unsigned portLONG ulBaudRateCounter;
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85 unsigned portCHAR ucByte;
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87 portENTER_CRITICAL();
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89 /* Create the queues used by the com test task. */
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90 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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91 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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93 /* Calculate the baud rate register value from the equation in the
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95 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned portLONG ) 1;
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97 /* Set the baud rate. */
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98 ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );
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99 outb( UBRRL, ucByte );
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101 ulBaudRateCounter >>= ( unsigned portLONG ) 8;
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102 ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );
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103 outb( UBRRH, ucByte );
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105 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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106 later. Also enable the Rx and Tx. */
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107 outb( UCSRB, serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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109 /* Set the data bits to 8. */
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110 outb( UCSRC, serUCSRC_SELECT | serEIGHT_DATA_BITS );
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112 portEXIT_CRITICAL();
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114 /* Unlike other ports, this serial code does not allow for more than one
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115 com port. We therefore don't return a pointer to a port structure and can
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116 instead just return NULL. */
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119 /*-----------------------------------------------------------*/
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121 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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123 /* Get the next character from the buffer. Return false if no characters
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124 are available, or arrive before xBlockTime expires. */
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125 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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134 /*-----------------------------------------------------------*/
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136 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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138 /* Return false if after the block time there is no room on the Tx queue. */
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139 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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148 /*-----------------------------------------------------------*/
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150 void vSerialClose( xComPortHandle xPort )
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152 unsigned portCHAR ucByte;
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154 /* Turn off the interrupts. We may also want to delete the queues and/or
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155 re-install the original ISR. */
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157 portENTER_CRITICAL();
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161 ucByte &= ~serRX_INT_ENABLE;
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162 outb( UCSRB, ucByte );
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164 portEXIT_CRITICAL();
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166 /*-----------------------------------------------------------*/
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168 __interrupt void SIG_UART_RECV( void )
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170 signed portCHAR cChar;
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172 /* Get the character and post it on the queue of Rxed characters.
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173 If the post causes a task to wake force a context switch as the woken task
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174 may have a higher priority than the task we have interrupted. */
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177 if( xQueueSendFromISR( xRxedChars, &cChar, pdFALSE ) )
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182 /*-----------------------------------------------------------*/
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184 __interrupt void SIG_UART_DATA( void )
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186 signed portCHAR cChar, cTaskWoken;
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188 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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190 /* Send the next character queued for Tx. */
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191 outb( UDR, cChar );
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195 /* Queue empty, nothing to send. */
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