2 FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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32 >>>NOTE<<< The modification to the GPL is included to allow you to
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33 distribute a combined work that includes FreeRTOS without being obliged to
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34 provide the source code for proprietary components outside of the FreeRTOS
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35 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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36 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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37 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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38 more details. You should have received a copy of the GNU General Public
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39 License and the FreeRTOS license exception along with FreeRTOS; if not it
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40 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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41 by writing to Richard Barry, contact details for whom are available on the
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46 ***************************************************************************
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48 * Having a problem? Start by reading the FAQ "My application does *
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49 * not run, what could be wrong?" *
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51 * http://www.FreeRTOS.org/FAQHelp.html *
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53 ***************************************************************************
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56 http://www.FreeRTOS.org - Documentation, training, latest versions, license
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57 and contact details.
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59 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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60 including FreeRTOS+Trace - an indispensable productivity tool.
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62 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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63 the code with commercial support, indemnification, and middleware, under
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64 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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65 provide a safety engineered and independently SIL3 certified version under
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66 the SafeRTOS brand: http://www.SafeRTOS.com.
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70 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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72 ***Note*** This example uses queues to send each character into an interrupt
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73 service routine and out of an interrupt service routine individually. This
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74 is done to demonstrate queues being used in an interrupt, and to deliberately
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75 load the system to test the FreeRTOS port. It is *NOT* meant to be an
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76 example of an efficient implementation. An efficient implementation should
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77 use FIFOs or DMA if available, and only use FreeRTOS API functions when
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78 enough has been received to warrant a task being unblocked to process the
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82 /* Scheduler includes. */
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83 #include "FreeRTOS.h"
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86 #include "comtest2.h"
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88 /* Library includes. */
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91 /* Demo application includes. */
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93 /*-----------------------------------------------------------*/
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95 /* Register bit definitions. */
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96 #define serRX_INT_ENABLE 0x10
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97 #define serTX_INT_ENABLE 0x08
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98 #define serRX_ENABLE 0x02
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99 #define serTX_ENABLE 0x01
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100 #define serORE_ERROR_BIT 0x08
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101 #define serFRE_ERROR_BIT 0x10
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102 #define serPE_ERROR_BIT 0x20
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103 #define serRX_INT 0x04
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104 #define serTX_INT 0x02
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106 /* Misc defines. */
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107 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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108 #define serNO_BLOCK ( ( portTickType ) 0 )
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110 /*-----------------------------------------------------------*/
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112 /* The queue used to hold received characters. */
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113 static xQueueHandle xRxedChars;
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114 static xQueueHandle xCharsForTx;
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116 /*-----------------------------------------------------------*/
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119 * See the serial2.h header file.
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121 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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123 /* Create the queues used to hold Rx/Tx characters. */
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124 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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125 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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127 /* If the queues were created correctly then setup the serial port
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129 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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131 /* Ensure interrupts don't fire during the init process. Interrupts
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132 will be enabled automatically when the first task start running. */
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133 portDISABLE_INTERRUPTS();
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135 /* Configure P21 and P22 for use by the UART. */
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136 FM3_GPIO->PFR2 |= ( 1 << 0x01 ) | ( 1 << 0x02 );
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138 /* SIN0_0 and SOT0_0. */
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139 FM3_GPIO->EPFR07 |= ( 1 << 6 );
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142 FM3_MFS0_UART->SCR = 0x80;
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144 /* Enable output in mode 0. */
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145 FM3_MFS0_UART->SMR = 0x01;
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147 /* Clear all errors that may already be present. */
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148 FM3_MFS0_UART->SSR = 0x00;
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149 FM3_MFS0_UART->ESCR = 0x00;
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151 FM3_MFS0_UART->BGR = ( configCPU_CLOCK_HZ / 2UL ) / ( ulWantedBaud - 1UL );
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153 /* Enable Rx, Tx, and the Rx interrupt. */
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154 FM3_MFS0_UART->SCR |= ( serRX_ENABLE | serTX_ENABLE | serRX_INT_ENABLE );
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156 /* Configure the NVIC for UART interrupts. */
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157 NVIC_ClearPendingIRQ( MFS0RX_IRQn );
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158 NVIC_EnableIRQ( MFS0RX_IRQn );
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160 /* The priority *MUST* be at or below
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161 configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY as FreeRTOS API functions
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162 are called in the interrupt handler. */
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163 NVIC_SetPriority( MFS0RX_IRQn, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
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165 /* Do the same for the Tx interrupts. */
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166 NVIC_ClearPendingIRQ( MFS0TX_IRQn );
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167 NVIC_EnableIRQ( MFS0TX_IRQn );
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169 /* The priority *MUST* be at or below
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170 configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY as FreeRTOS API functions
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171 are called in the interrupt handler. */
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172 NVIC_SetPriority( MFS0TX_IRQn, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
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175 /* This demo file only supports a single port but we have to return
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176 something to comply with the standard demo header file. */
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177 return ( xComPortHandle ) 0;
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179 /*-----------------------------------------------------------*/
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181 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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183 /* The port handle is not required as this driver only supports one port. */
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186 /* Get the next character from the buffer. Return false if no characters
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187 are available, or arrive before xBlockTime expires. */
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188 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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197 /*-----------------------------------------------------------*/
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199 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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201 signed char *pxNext;
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203 /* A couple of parameters that this port does not use. */
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204 ( void ) usStringLength;
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207 /* NOTE: This implementation does not handle the queue being full as no
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208 block time is used! */
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210 /* The port handle is not required as this driver only supports one UART. */
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213 /* Send each character in the string, one at a time. */
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214 pxNext = ( signed char * ) pcString;
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217 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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221 /*-----------------------------------------------------------*/
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223 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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225 signed portBASE_TYPE xReturn;
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227 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS )
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231 /* Enable the UART Tx interrupt. */
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232 FM3_MFS0_UART->SCR |= serTX_INT_ENABLE;
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241 /*-----------------------------------------------------------*/
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243 void vSerialClose( xComPortHandle xPort )
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245 /* Not supported as not required by the demo application. */
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247 /*-----------------------------------------------------------*/
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249 void MFS0RX_IRQHandler( void )
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251 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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254 if( ( FM3_MFS0_UART->SSR & ( serORE_ERROR_BIT | serFRE_ERROR_BIT | serPE_ERROR_BIT ) ) != 0 )
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256 /* A PE, ORE or FRE error occurred. Clear it. */
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257 FM3_MFS0_UART->SSR |= ( 1 << 7 );
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258 cChar = FM3_MFS0_UART->RDR;
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260 else if( FM3_MFS0_UART->SSR & serRX_INT )
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262 /* A character has been received on the USART, send it to the Rx
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264 cChar = FM3_MFS0_UART->RDR;
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265 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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268 /* If sending or receiving from a queue has caused a task to unblock, and
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269 the unblocked task has a priority equal to or higher than the currently
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270 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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271 will have automatically been set to pdTRUE within the queue send or receive
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272 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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273 directly to the higher priority unblocked task. */
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274 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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276 /*-----------------------------------------------------------*/
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278 void MFS0TX_IRQHandler( void )
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280 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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283 if( FM3_MFS0_UART->SSR & serTX_INT )
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285 /* The interrupt was caused by the TX register becoming empty. Are
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286 there any more characters to transmit? */
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287 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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289 /* A character was retrieved from the queue so can be sent to the
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291 FM3_MFS0_UART->TDR = cChar;
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295 /* Disable the Tx interrupt. */
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296 FM3_MFS0_UART->SCR &= ~serTX_INT_ENABLE;
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300 /* If sending or receiving from a queue has caused a task to unblock, and
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301 the unblocked task has a priority equal to or higher than the currently
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302 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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303 will have automatically been set to pdTRUE within the queue send or receive
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304 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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305 directly to the higher priority unblocked task. */
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306 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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