2 FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 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 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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31 * This is a concise, step by step, 'hands on' guide that describes both *
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32 * general multitasking concepts and FreeRTOS specifics. It presents and *
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33 * explains numerous examples that are written using the FreeRTOS API. *
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34 * Full source code for all the examples is provided in an accompanying *
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37 ***************************************************************************
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38 ***************************************************************************
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40 Please ensure to read the configuration and relevant port sections of the
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41 online documentation.
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43 http://www.FreeRTOS.org - Documentation, latest information, license and
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46 http://www.SafeRTOS.com - A version that is certified for use in safety
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49 http://www.OpenRTOS.com - Commercial support, development, porting,
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50 licensing and training services.
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55 * BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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57 * This file only supports UART 2
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60 /* Standard includes. */
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63 /* Scheduler includes. */
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64 #include "FreeRTOS.h"
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68 /* Demo application includes. */
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71 /* The queue used to hold received characters. */
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72 static xQueueHandle xRxedChars;
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74 /* The queue used to hold characters waiting transmission. */
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75 static xQueueHandle xCharsForTx;
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77 static volatile portSHORT sTHREEmpty;
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79 /*-----------------------------------------------------------*/
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81 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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83 portENTER_CRITICAL();
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85 /* Create the queues used by the com test task. */
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86 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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87 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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89 /* Initialize UART asynchronous mode */
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90 BGR02 = configPER_CLOCK_HZ / ulWantedBaud;
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92 SCR02 = 0x17; /* 8N1 */
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93 SMR02 = 0x0d; /* enable SOT3, Reset, normal mode */
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94 SSR02 = 0x02; /* LSB first, enable receive interrupts */
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96 PFR20_D0 = 1; /* enable UART */
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97 PFR20_D1 = 1; /* enable UART */
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99 EPFR20_D1 = 0; /* enable UART */
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101 portEXIT_CRITICAL();
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103 /* Unlike other ports, this serial code does not allow for more than one
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104 com port. We therefore don't return a pointer to a port structure and can
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105 instead just return NULL. */
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108 /*-----------------------------------------------------------*/
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110 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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112 /* Get the next character from the buffer. Return false if no characters
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113 are available, or arrive before xBlockTime expires. */
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114 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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123 /*-----------------------------------------------------------*/
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125 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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127 signed portBASE_TYPE xReturn;
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129 /* Transmit a character. */
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130 portENTER_CRITICAL();
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132 if( sTHREEmpty == pdTRUE )
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134 /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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135 there are no characters queued to be transmitted - so we can
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136 write the character directly to the shift Tx register. */
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137 sTHREEmpty = pdFALSE;
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143 /* sTHREEmpty is false, so there are still characters waiting to be
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144 transmitted. We have to queue this character so it gets
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145 transmitted in turn. */
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147 /* Return false if after the block time there is no room on the Tx
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148 queue. It is ok to block inside a critical section as each task
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149 maintains it's own critical section status. */
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150 if (xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdTRUE)
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160 if (pdPASS == xReturn)
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162 /* Turn on the Tx interrupt so the ISR will remove the character from the
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163 queue and send it. This does not need to be in a critical section as
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164 if the interrupt has already removed the character the next interrupt
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165 will simply turn off the Tx interrupt again. */
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170 portEXIT_CRITICAL();
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174 /*-----------------------------------------------------------*/
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177 * UART RX interrupt service routine.
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179 __interrupt void UART2_RxISR (void)
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181 signed portCHAR cChar;
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182 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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184 /* Get the character from the UART and post it on the queue of Rxed
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188 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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190 if( xHigherPriorityTaskWoken )
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192 /*If the post causes a task to wake force a context switch
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193 as the woken task may have a higher priority than the task we have
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195 portYIELD_FROM_ISR();
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199 /*-----------------------------------------------------------*/
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202 * UART Tx interrupt service routine.
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204 __interrupt void UART2_TxISR (void)
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206 signed portCHAR cChar;
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207 signed portBASE_TYPE xTaskWoken = pdFALSE;
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209 /* The previous character has been transmitted. See if there are any
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210 further characters waiting transmission. */
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211 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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213 /* There was another character queued - transmit it now. */
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218 /* There were no other characters to transmit. */
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219 sTHREEmpty = pdTRUE;
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221 /* Disable transmit interrupts */
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