2 FreeRTOS V6.0.0 - Copyright (C) 2009 Real Time Engineers Ltd.
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4 This file is part of the FreeRTOS distribution.
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6 FreeRTOS is free software; you can redistribute it and/or modify it under
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7 the terms of the GNU General Public License (version 2) as published by the
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8 Free Software Foundation and modified by the FreeRTOS exception.
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9 **NOTE** The exception to the GPL is included to allow you to distribute a
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10 combined work that includes FreeRTOS without being obliged to provide the
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11 source code for proprietary components outside of the FreeRTOS kernel.
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12 Alternative commercial license and support terms are also available upon
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13 request. See the licensing section of http://www.FreeRTOS.org for full
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16 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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17 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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18 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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21 You should have received a copy of the GNU General Public License along
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22 with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
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23 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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26 ***************************************************************************
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28 * The FreeRTOS eBook and reference manual are available to purchase for a *
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29 * small fee. Help yourself get started quickly while also helping the *
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30 * FreeRTOS project! See http://www.FreeRTOS.org/Documentation for details *
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32 ***************************************************************************
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36 Please ensure to read the configuration and relevant port sections of the
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37 online documentation.
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39 http://www.FreeRTOS.org - Documentation, latest information, license and
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42 http://www.SafeRTOS.com - A version that is certified for use in safety
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45 http://www.OpenRTOS.com - Commercial support, development, porting,
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46 licensing and training services.
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52 + The function xPortInitMinimal() has been renamed to
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53 xSerialPortInitMinimal() and the function xPortInit() has been renamed
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54 to xSerialPortInit().
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58 + Delay periods are now specified using variables and constants of
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59 portTickType rather than unsigned long.
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60 + xQueueReceiveFromISR() used in place of xQueueReceive() within the ISR.
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64 + Replaced the inb() and outb() functions with direct memory
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65 access. This allows the port to be built with the 20050414 build of
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69 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */
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73 #include <avr/interrupt.h>
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74 #include "FreeRTOS.h"
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79 #define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 )
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81 /* Constants for writing to UCSRB. */
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82 #define serRX_INT_ENABLE ( ( unsigned char ) 0x80 )
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83 #define serRX_ENABLE ( ( unsigned char ) 0x10 )
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84 #define serTX_ENABLE ( ( unsigned char ) 0x08 )
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85 #define serTX_INT_ENABLE ( ( unsigned char ) 0x20 )
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87 /* Constants for writing to UCSRC. */
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88 #define serUCSRC_SELECT ( ( unsigned char ) 0x80 )
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89 #define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 )
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91 static xQueueHandle xRxedChars;
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92 static xQueueHandle xCharsForTx;
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94 #define vInterruptOn() \
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96 unsigned char ucByte; \
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99 ucByte |= serTX_INT_ENABLE; \
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102 /*-----------------------------------------------------------*/
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104 #define vInterruptOff() \
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106 unsigned char ucInByte; \
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108 ucInByte = UCSRB; \
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109 ucInByte &= ~serTX_INT_ENABLE; \
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110 UCSRB = ucInByte; \
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112 /*-----------------------------------------------------------*/
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114 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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116 unsigned long ulBaudRateCounter;
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117 unsigned char ucByte;
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119 portENTER_CRITICAL();
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121 /* Create the queues used by the com test task. */
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122 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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123 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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125 /* Calculate the baud rate register value from the equation in the
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127 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1;
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129 /* Set the baud rate. */
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130 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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133 ulBaudRateCounter >>= ( unsigned long ) 8;
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134 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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137 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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138 later. Also enable the Rx and Tx. */
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139 UCSRB = ( serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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141 /* Set the data bits to 8. */
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142 UCSRC = ( serUCSRC_SELECT | serEIGHT_DATA_BITS );
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144 portEXIT_CRITICAL();
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146 /* Unlike other ports, this serial code does not allow for more than one
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147 com port. We therefore don't return a pointer to a port structure and can
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148 instead just return NULL. */
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151 /*-----------------------------------------------------------*/
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153 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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155 /* Only one port is supported. */
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158 /* Get the next character from the buffer. Return false if no characters
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159 are available, or arrive before xBlockTime expires. */
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160 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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169 /*-----------------------------------------------------------*/
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171 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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173 /* Only one port is supported. */
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176 /* Return false if after the block time there is no room on the Tx queue. */
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177 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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186 /*-----------------------------------------------------------*/
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188 void vSerialClose( xComPortHandle xPort )
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190 unsigned char ucByte;
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192 /* The parameter is not used. */
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195 /* Turn off the interrupts. We may also want to delete the queues and/or
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196 re-install the original ISR. */
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198 portENTER_CRITICAL();
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202 ucByte &= ~serRX_INT_ENABLE;
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205 portEXIT_CRITICAL();
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207 /*-----------------------------------------------------------*/
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209 SIGNAL( SIG_UART_RECV )
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212 signed portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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214 /* Get the character and post it on the queue of Rxed characters.
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215 If the post causes a task to wake force a context switch as the woken task
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216 may have a higher priority than the task we have interrupted. */
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219 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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221 if( xHigherPriorityTaskWoken != pdFALSE )
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226 /*-----------------------------------------------------------*/
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228 SIGNAL( SIG_UART_DATA )
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230 signed char cChar, cTaskWoken;
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232 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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234 /* Send the next character queued for Tx. */
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239 /* Queue empty, nothing to send. */
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