2 FreeRTOS V8.1.2 - Copyright (C) 2014 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS provides completely free yet professionally developed, *
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10 * robust, strictly quality controlled, supported, and cross *
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11 * platform software that has become a de facto standard. *
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13 * Help yourself get started quickly and support the FreeRTOS *
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14 * project by purchasing a FreeRTOS tutorial book, reference *
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15 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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19 ***************************************************************************
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21 This file is part of the FreeRTOS distribution.
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23 FreeRTOS is free software; you can redistribute it and/or modify it under
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24 the terms of the GNU General Public License (version 2) as published by the
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25 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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27 >>! NOTE: The modification to the GPL is included to allow you to !<<
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28 >>! distribute a combined work that includes FreeRTOS without being !<<
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29 >>! obliged to provide the source code for proprietary components !<<
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30 >>! outside of the FreeRTOS kernel. !<<
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32 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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33 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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34 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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35 link: http://www.freertos.org/a00114.html
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39 ***************************************************************************
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41 * Having a problem? Start by reading the FAQ "My application does *
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42 * not run, what could be wrong?" *
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44 * http://www.FreeRTOS.org/FAQHelp.html *
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46 ***************************************************************************
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48 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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49 license and Real Time Engineers Ltd. contact details.
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51 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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52 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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53 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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55 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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56 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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57 licenses offer ticketed support, indemnification and middleware.
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59 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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60 engineered and independently SIL3 certified version for use in safety and
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61 mission critical applications that require provable dependability.
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69 + Made serial ISR handling more complete and robust.
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73 + Split serial.c into serial.c and serialISR.c. serial.c can be
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74 compiled using ARM or THUMB modes. serialISR.c must always be
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75 compiled in ARM mode.
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76 + Another small change to cSerialPutChar().
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80 + In cSerialPutChar() an extra check is made to ensure the post to
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81 the queue was successful if then attempting to retrieve the posted
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87 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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89 This file contains all the serial port components that can be compiled to
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90 either ARM or THUMB mode. Components that must be compiled to ARM mode are
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91 contained in serialISR.c.
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94 /* Standard includes. */
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97 /* Scheduler includes. */
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98 #include "FreeRTOS.h"
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102 /* Demo application includes. */
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103 #include "serial.h"
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105 /*-----------------------------------------------------------*/
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107 /* Constants to setup and access the UART. */
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108 #define serDLAB ( ( unsigned char ) 0x80 )
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109 #define serENABLE_INTERRUPTS ( ( unsigned char ) 0x03 )
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110 #define serNO_PARITY ( ( unsigned char ) 0x00 )
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111 #define ser1_STOP_BIT ( ( unsigned char ) 0x00 )
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112 #define ser8_BIT_CHARS ( ( unsigned char ) 0x03 )
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113 #define serFIFO_ON ( ( unsigned char ) 0x01 )
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114 #define serCLEAR_FIFO ( ( unsigned char ) 0x06 )
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115 #define serWANTED_CLOCK_SCALING ( ( unsigned long ) 16 )
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117 /* Constants to setup and access the VIC. */
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118 #define serUART0_VIC_CHANNEL ( ( unsigned long ) 0x0006 )
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119 #define serUART0_VIC_CHANNEL_BIT ( ( unsigned long ) 0x0040 )
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120 #define serUART0_VIC_ENABLE ( ( unsigned long ) 0x0020 )
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121 #define serCLEAR_VIC_INTERRUPT ( ( unsigned long ) 0 )
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123 #define serINVALID_QUEUE ( ( QueueHandle_t ) 0 )
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124 #define serHANDLE ( ( xComPortHandle ) 1 )
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125 #define serNO_BLOCK ( ( TickType_t ) 0 )
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127 /*-----------------------------------------------------------*/
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129 /* Queues used to hold received characters, and characters waiting to be
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131 static QueueHandle_t xRxedChars;
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132 static QueueHandle_t xCharsForTx;
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134 /*-----------------------------------------------------------*/
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136 /* Communication flag between the interrupt service routine and serial API. */
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137 static volatile long *plTHREEmpty;
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140 * The queues are created in serialISR.c as they are used from the ISR.
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141 * Obtain references to the queues and THRE Empty flag.
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143 extern void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, QueueHandle_t *pxRxedChars, QueueHandle_t *pxCharsForTx, long volatile **pplTHREEmptyFlag );
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145 /*-----------------------------------------------------------*/
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147 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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149 unsigned long ulDivisor, ulWantedClock;
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150 xComPortHandle xReturn = serHANDLE;
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151 extern void ( vUART_ISR_Wrapper )( void );
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153 /* The queues are used in the serial ISR routine, so are created from
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154 serialISR.c (which is always compiled to ARM mode. */
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155 vSerialISRCreateQueues( uxQueueLength, &xRxedChars, &xCharsForTx, &plTHREEmpty );
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158 ( xRxedChars != serINVALID_QUEUE ) &&
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159 ( xCharsForTx != serINVALID_QUEUE ) &&
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160 ( ulWantedBaud != ( unsigned long ) 0 )
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163 portENTER_CRITICAL();
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165 /* Setup the baud rate: Calculate the divisor value. */
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166 ulWantedClock = ulWantedBaud * serWANTED_CLOCK_SCALING;
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167 ulDivisor = configCPU_CLOCK_HZ / ulWantedClock;
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169 /* Set the DLAB bit so we can access the divisor. */
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170 UART0_LCR |= serDLAB;
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172 /* Setup the divisor. */
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173 UART0_DLL = ( unsigned char ) ( ulDivisor & ( unsigned long ) 0xff );
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175 UART0_DLM = ( unsigned char ) ( ulDivisor & ( unsigned long ) 0xff );
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177 /* Turn on the FIFO's and clear the buffers. */
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178 UART0_FCR = ( serFIFO_ON | serCLEAR_FIFO );
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180 /* Setup transmission format. */
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181 UART0_LCR = serNO_PARITY | ser1_STOP_BIT | ser8_BIT_CHARS;
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183 /* Setup the VIC for the UART. */
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184 VICIntSelect &= ~( serUART0_VIC_CHANNEL_BIT );
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185 VICIntEnable |= serUART0_VIC_CHANNEL_BIT;
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186 VICVectAddr1 = ( long ) vUART_ISR_Wrapper;
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187 VICVectCntl1 = serUART0_VIC_CHANNEL | serUART0_VIC_ENABLE;
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189 /* Enable UART0 interrupts. */
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190 UART0_IER |= serENABLE_INTERRUPTS;
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192 portEXIT_CRITICAL();
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196 xReturn = ( xComPortHandle ) 0;
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201 /*-----------------------------------------------------------*/
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203 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
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205 /* The port handle is not required as this driver only supports UART0. */
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208 /* Get the next character from the buffer. Return false if no characters
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209 are available, or arrive before xBlockTime expires. */
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210 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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219 /*-----------------------------------------------------------*/
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221 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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223 signed char *pxNext;
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225 /* NOTE: This implementation does not handle the queue being full as no
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226 block time is used! */
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228 /* The port handle is not required as this driver only supports UART0. */
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230 ( void ) usStringLength;
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232 /* Send each character in the string, one at a time. */
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233 pxNext = ( signed char * ) pcString;
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236 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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240 /*-----------------------------------------------------------*/
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242 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
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244 signed portBASE_TYPE xReturn;
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246 /* This demo driver only supports one port so the parameter is not used. */
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249 portENTER_CRITICAL();
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251 /* Is there space to write directly to the UART? */
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252 if( *plTHREEmpty == ( long ) pdTRUE )
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254 /* We wrote the character directly to the UART, so was
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256 *plTHREEmpty = pdFALSE;
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257 UART0_THR = cOutChar;
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262 /* We cannot write directly to the UART, so queue the character.
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263 Block for a maximum of xBlockTime if there is no space in the
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265 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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267 /* Depending on queue sizing and task prioritisation: While we
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268 were blocked waiting to post interrupts were not disabled. It is
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269 possible that the serial ISR has emptied the Tx queue, in which
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270 case we need to start the Tx off again. */
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271 if( ( *plTHREEmpty == ( long ) pdTRUE ) && ( xReturn == pdPASS ) )
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273 xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
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274 *plTHREEmpty = pdFALSE;
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275 UART0_THR = cOutChar;
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279 portEXIT_CRITICAL();
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283 /*-----------------------------------------------------------*/
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285 void vSerialClose( xComPortHandle xPort )
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287 /* Not supported as not required by the demo application. */
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290 /*-----------------------------------------------------------*/
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