2 FreeRTOS V9.0.0rc1 - Copyright (C) 2016 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 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
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13 ***************************************************************************
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14 >>! NOTE: The modification to the GPL is included to allow you to !<<
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15 >>! distribute a combined work that includes FreeRTOS without being !<<
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16 >>! obliged to provide the source code for proprietary components !<<
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17 >>! outside of the FreeRTOS kernel. !<<
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18 ***************************************************************************
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20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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23 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * FreeRTOS provides completely free yet professionally developed, *
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28 * robust, strictly quality controlled, supported, and cross *
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29 * platform software that is more than just the market leader, it *
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30 * is the industry's de facto standard. *
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32 * Help yourself get started quickly while simultaneously helping *
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33 * to support the FreeRTOS project by purchasing a FreeRTOS *
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34 * tutorial book, reference manual, or both: *
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35 * http://www.FreeRTOS.org/Documentation *
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37 ***************************************************************************
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39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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40 the FAQ page "My application does not run, what could be wrong?". Have you
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41 defined configASSERT()?
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43 http://www.FreeRTOS.org/support - In return for receiving this top quality
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44 embedded software for free we request you assist our global community by
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45 participating in the support forum.
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47 http://www.FreeRTOS.org/training - Investing in training allows your team to
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48 be as productive as possible as early as possible. Now you can receive
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49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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50 Ltd, and the world's leading authority on the world's leading RTOS.
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52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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61 licenses offer ticketed support, indemnification and commercial middleware.
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63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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64 engineered and independently SIL3 certified version for use in safety and
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65 mission critical applications that require provable dependability.
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71 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR USART1.
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73 ***Note*** This example uses queues to send each character into an interrupt
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74 service routine and out of an interrupt service routine individually. This
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75 is done to demonstrate queues being used in an interrupt, and to deliberately
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76 load the system to test the FreeRTOS port. It is *NOT* meant to be an
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77 example of an efficient implementation. An efficient implementation should
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78 use FIFO's or DMA if available, and only use FreeRTOS API functions when
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79 enough has been received to warrant a task being unblocked to process the
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83 /* Scheduler includes. */
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84 #include "FreeRTOS.h"
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87 #include "comtest2.h"
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89 /* Library includes. */
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92 /* Demo application includes. */
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93 #include "demo_serial.h"
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94 /*-----------------------------------------------------------*/
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97 #define serINVALID_QUEUE ( ( QueueHandle_t ) 0 )
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98 #define serNO_BLOCK ( ( TickType_t ) 0 )
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99 #define serPMC_USART_ID ( BOARD_ID_USART )
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101 /* The USART supported by this file. */
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102 #define serUSART_PORT ( USART0 )
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103 #define serUSART_IRQ ( USART0_IRQn )
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105 /* Every bit in the interrupt mask. */
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106 #define serMASK_ALL_INTERRUPTS ( 0xffffffffUL )
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108 /*-----------------------------------------------------------*/
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110 /* The queue used to hold received characters. */
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111 static QueueHandle_t xRxedChars;
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112 static QueueHandle_t xCharsForTx;
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114 /*-----------------------------------------------------------*/
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118 * See the serial.h header file.
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120 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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123 xComPortHandle xReturn;
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124 const sam_usart_opt_t xUSARTSettings =
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129 US_MR_NBSTOP_1_BIT,
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130 US_MR_CHMODE_NORMAL,
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131 0 /* Only used in IrDA mode. */
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134 /* Create the queues used to hold Rx/Tx characters. */
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135 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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136 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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138 /* If the queues were created correctly then setup the serial port
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140 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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142 /* Enable the peripheral clock in the PMC. */
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143 pmc_enable_periph_clk( serPMC_USART_ID );
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145 /* Configure USART in serial mode. */
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146 usart_init_rs232( serUSART_PORT, &xUSARTSettings, sysclk_get_cpu_hz() );
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148 /* Disable all the interrupts. */
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149 usart_disable_interrupt( serUSART_PORT, serMASK_ALL_INTERRUPTS );
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151 /* Enable the receiver and transmitter. */
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152 usart_enable_tx( serUSART_PORT );
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153 usart_enable_rx( serUSART_PORT );
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155 /* Clear any characters before enabling interrupt. */
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156 usart_getchar( serUSART_PORT, &ulChar );
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158 /* Enable Rx end interrupt. */
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159 usart_enable_interrupt( serUSART_PORT, US_IER_RXRDY );
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161 /* Configure and enable interrupt of USART. */
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162 NVIC_SetPriority( serUSART_IRQ, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
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163 NVIC_EnableIRQ( serUSART_IRQ );
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167 xReturn = ( xComPortHandle ) 0;
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170 /* This demo file only supports a single port but we have to return
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171 something to comply with the standard demo header file. */
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174 /*-----------------------------------------------------------*/
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176 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
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178 /* The port handle is not required as this driver only supports one port. */
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181 /* Get the next character from the buffer. Return false if no characters
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182 are available, or arrive before xBlockTime expires. */
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183 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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192 /*-----------------------------------------------------------*/
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194 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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196 signed char *pxNext;
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198 /* A couple of parameters that this port does not use. */
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199 ( void ) usStringLength;
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202 /* NOTE: This implementation does not handle the queue being full as no
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203 block time is used! */
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205 /* The port handle is not required as this driver only supports USART1. */
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208 /* Send each character in the string, one at a time. */
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209 pxNext = ( signed char * ) pcString;
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212 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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216 /*-----------------------------------------------------------*/
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218 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
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220 signed portBASE_TYPE xReturn;
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222 /* This simple example only supports one port. */
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225 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS )
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228 usart_enable_interrupt( serUSART_PORT, US_IER_TXRDY );
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237 /*-----------------------------------------------------------*/
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239 void vSerialClose( xComPortHandle xPort )
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241 /* Not supported as not required by the demo application. */
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244 /*-----------------------------------------------------------*/
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247 * It should be noted that the com test tasks (which use make use of this file)
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248 * are included to demonstrate queues being used to communicate between tasks
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249 * and interrupts, and to demonstrate a context switch being performed from
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250 * inside an interrupt service routine. The serial driver used here is *not*
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251 * intended to represent an efficient implementation. Real applications should
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252 * make use of the USARTS peripheral DMA channel (PDC).
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254 void USART0_Handler( void )
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256 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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259 uint32_t ulUSARTStatus, ulUSARTMask;
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261 ulUSARTStatus = usart_get_status( serUSART_PORT );
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262 ulUSARTMask = usart_get_interrupt_mask( serUSART_PORT );
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263 ulUSARTStatus &= ulUSARTMask;
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265 if( ( ulUSARTStatus & US_CSR_TXRDY ) != 0UL )
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267 /* The interrupt was caused by the TX register becoming empty. Are
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268 there any more characters to transmit? */
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269 if( xQueueReceiveFromISR( xCharsForTx, &ucChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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271 /* A character was retrieved from the queue so can be sent to the
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273 usart_putchar( serUSART_PORT, ( uint32_t ) ucChar );
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277 usart_disable_interrupt( serUSART_PORT, US_IER_TXRDY );
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281 if( ( ulUSARTStatus & US_CSR_RXRDY ) != 0UL )
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283 /* A character has been received on the USART, send it to the Rx
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285 usart_getchar( serUSART_PORT, &ulChar );
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286 ucChar = ( uint8_t ) ( ulChar & 0xffUL );
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287 xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken );
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290 /* If sending or receiving from a queue has caused a task to unblock, and
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291 the unblocked task has a priority equal to or higher than the currently
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292 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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293 will have automatically been set to pdTRUE within the queue send or receive
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294 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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295 directly to the higher priority unblocked task. */
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296 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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