2 FreeRTOS.org V5.0.3 - Copyright (C) 2003-2008 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 ***************************************************************************
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29 * SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, *
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30 * and even write all or part of your application on your behalf. *
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31 * See http://www.OpenRTOS.com for details of the services we provide to *
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32 * expedite your project. *
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34 ***************************************************************************
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35 ***************************************************************************
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37 Please ensure to read the configuration and relevant port sections of the
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38 online documentation.
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40 http://www.FreeRTOS.org - Documentation, latest information, license and
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43 http://www.SafeRTOS.com - A version that is certified for use in safety
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46 http://www.OpenRTOS.com - Commercial support, development, porting,
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47 licensing and training services.
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52 * BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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54 * This file only supports UART 2
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57 /* Standard includes. */
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60 /* Scheduler includes. */
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61 #include "FreeRTOS.h"
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65 /* Demo application includes. */
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68 /* The queue used to hold received characters. */
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69 static xQueueHandle xRxedChars;
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71 /* The queue used to hold characters waiting transmission. */
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72 static xQueueHandle xCharsForTx;
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74 static volatile portSHORT sTHREEmpty;
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76 /*-----------------------------------------------------------*/
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78 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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80 portENTER_CRITICAL();
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82 /* Create the queues used by the com test task. */
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83 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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84 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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86 /* Initialize UART asynchronous mode */
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87 BGR02 = configPER_CLOCK_HZ / ulWantedBaud;
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89 SCR02 = 0x17; /* 8N1 */
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90 SMR02 = 0x0d; /* enable SOT3, Reset, normal mode */
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91 SSR02 = 0x02; /* LSB first, enable receive interrupts */
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93 PFR20_D0 = 1; /* enable UART */
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94 PFR20_D1 = 1; /* enable UART */
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96 EPFR20_D1 = 0; /* enable UART */
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98 portEXIT_CRITICAL();
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100 /* Unlike other ports, this serial code does not allow for more than one
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101 com port. We therefore don't return a pointer to a port structure and can
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102 instead just return NULL. */
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105 /*-----------------------------------------------------------*/
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107 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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109 /* Get the next character from the buffer. Return false if no characters
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110 are available, or arrive before xBlockTime expires. */
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111 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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120 /*-----------------------------------------------------------*/
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122 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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124 signed portBASE_TYPE xReturn;
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126 /* Transmit a character. */
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127 portENTER_CRITICAL();
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129 if( sTHREEmpty == pdTRUE )
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131 /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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132 there are no characters queued to be transmitted - so we can
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133 write the character directly to the shift Tx register. */
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134 sTHREEmpty = pdFALSE;
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140 /* sTHREEmpty is false, so there are still characters waiting to be
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141 transmitted. We have to queue this character so it gets
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142 transmitted in turn. */
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144 /* Return false if after the block time there is no room on the Tx
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145 queue. It is ok to block inside a critical section as each task
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146 maintains it's own critical section status. */
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147 if (xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdTRUE)
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157 if (pdPASS == xReturn)
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159 /* Turn on the Tx interrupt so the ISR will remove the character from the
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160 queue and send it. This does not need to be in a critical section as
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161 if the interrupt has already removed the character the next interrupt
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162 will simply turn off the Tx interrupt again. */
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167 portEXIT_CRITICAL();
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171 /*-----------------------------------------------------------*/
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174 * UART RX interrupt service routine.
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176 __interrupt void UART2_RxISR (void)
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178 signed portCHAR cChar;
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179 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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181 /* Get the character from the UART and post it on the queue of Rxed
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185 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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187 if( xHigherPriorityTaskWoken )
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189 /*If the post causes a task to wake force a context switch
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190 as the woken task may have a higher priority than the task we have
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192 portYIELD_FROM_ISR();
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196 /*-----------------------------------------------------------*/
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199 * UART Tx interrupt service routine.
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201 __interrupt void UART2_TxISR (void)
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203 signed portCHAR cChar;
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204 signed portBASE_TYPE xTaskWoken = pdFALSE;
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206 /* The previous character has been transmitted. See if there are any
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207 further characters waiting transmission. */
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208 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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210 /* There was another character queued - transmit it now. */
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215 /* There were no other characters to transmit. */
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216 sTHREEmpty = pdTRUE;
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218 /* Disable transmit interrupts */
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