2 * FreeRTOS Kernel V10.0.0
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3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software. If you wish to use our Amazon
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14 * FreeRTOS name, please do so in a fair use way that does not cause confusion.
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16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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18 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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19 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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20 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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23 * http://www.FreeRTOS.org
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24 * http://aws.amazon.com/freertos
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26 * 1 tab == 4 spaces!
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30 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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32 ***Note*** This example uses queues to send each character into an interrupt
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33 service routine and out of an interrupt service routine individually. This
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34 is done to demonstrate queues being used in an interrupt, and to deliberately
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35 load the system to test the FreeRTOS port. It is *NOT* meant to be an
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36 example of an efficient implementation. An efficient implementation should
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37 use FIFOs or DMA if available, and only use FreeRTOS API functions when
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38 enough has been received to warrant a task being unblocked to process the
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42 /* Scheduler includes. */
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43 #include "FreeRTOS.h"
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46 #include "comtest2.h"
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48 /* Library includes. */
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49 #include "mb9bf506n.h"
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50 #include "system_mb9bf50x.h"
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52 /* Demo application includes. */
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54 /*-----------------------------------------------------------*/
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56 /* Register bit definitions. */
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57 #define serRX_INT_ENABLE 0x10
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58 #define serTX_INT_ENABLE 0x08
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59 #define serRX_ENABLE 0x02
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60 #define serTX_ENABLE 0x01
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61 #define serORE_ERROR_BIT 0x08
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62 #define serFRE_ERROR_BIT 0x10
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63 #define serPE_ERROR_BIT 0x20
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64 #define serRX_INT 0x04
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65 #define serTX_INT 0x02
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68 #define serINVALID_QUEUE ( ( QueueHandle_t ) 0 )
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69 #define serNO_BLOCK ( ( TickType_t ) 0 )
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71 /*-----------------------------------------------------------*/
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73 /* The queue used to hold received characters. */
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74 static QueueHandle_t xRxedChars;
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75 static QueueHandle_t xCharsForTx;
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77 /*-----------------------------------------------------------*/
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80 * See the serial2.h header file.
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82 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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84 /* Create the queues used to hold Rx/Tx characters. */
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85 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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86 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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88 /* If the queues were created correctly then setup the serial port
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90 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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92 /* Ensure interrupts don't fire during the init process. Interrupts
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93 will be enabled automatically when the first task start running. */
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94 portDISABLE_INTERRUPTS();
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96 /* Configure P21 and P22 for use by the UART. */
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97 FM3_GPIO->PFR2 |= ( 1 << 0x01 ) | ( 1 << 0x02 );
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99 /* SIN0_0 and SOT0_0. */
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100 FM3_GPIO->EPFR07 |= ( 1 << 6 );
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103 FM3_MFS0_UART->SCR = 0x80;
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105 /* Enable output in mode 0. */
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106 FM3_MFS0_UART->SMR = 0x01;
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108 /* Clear all errors that may already be present. */
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109 FM3_MFS0_UART->SSR = 0x00;
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110 FM3_MFS0_UART->ESCR = 0x00;
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112 FM3_MFS0_UART->BGR = ( configCPU_CLOCK_HZ / 2UL ) / ( ulWantedBaud - 1UL );
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114 /* Enable Rx, Tx, and the Rx interrupt. */
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115 FM3_MFS0_UART->SCR |= ( serRX_ENABLE | serTX_ENABLE | serRX_INT_ENABLE );
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117 /* Configure the NVIC for UART interrupts. */
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118 NVIC_ClearPendingIRQ( MFS0RX_IRQn );
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119 NVIC_EnableIRQ( MFS0RX_IRQn );
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121 /* The priority *MUST* be at or below
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122 configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY as FreeRTOS API functions
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123 are called in the interrupt handler. */
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124 NVIC_SetPriority( MFS0RX_IRQn, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
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126 /* Do the same for the Tx interrupts. */
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127 NVIC_ClearPendingIRQ( MFS0TX_IRQn );
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128 NVIC_EnableIRQ( MFS0TX_IRQn );
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130 /* The priority *MUST* be at or below
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131 configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY as FreeRTOS API functions
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132 are called in the interrupt handler. */
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133 NVIC_SetPriority( MFS0TX_IRQn, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
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136 /* This demo file only supports a single port but we have to return
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137 something to comply with the standard demo header file. */
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138 return ( xComPortHandle ) 0;
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140 /*-----------------------------------------------------------*/
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142 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
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144 /* The port handle is not required as this driver only supports one port. */
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147 /* Get the next character from the buffer. Return false if no characters
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148 are available, or arrive before xBlockTime expires. */
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149 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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158 /*-----------------------------------------------------------*/
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160 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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162 signed char *pxNext;
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164 /* A couple of parameters that this port does not use. */
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165 ( void ) usStringLength;
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168 /* NOTE: This implementation does not handle the queue being full as no
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169 block time is used! */
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171 /* The port handle is not required as this driver only supports one UART. */
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174 /* Send each character in the string, one at a time. */
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175 pxNext = ( signed char * ) pcString;
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178 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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182 /*-----------------------------------------------------------*/
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184 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
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186 signed portBASE_TYPE xReturn;
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188 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS )
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192 /* Enable the UART Tx interrupt. */
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193 FM3_MFS0_UART->SCR |= serTX_INT_ENABLE;
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202 /*-----------------------------------------------------------*/
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204 void vSerialClose( xComPortHandle xPort )
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206 /* Not supported as not required by the demo application. */
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208 /*-----------------------------------------------------------*/
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210 void MFS0RX_IRQHandler( void )
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212 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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215 if( ( FM3_MFS0_UART->SSR & ( serORE_ERROR_BIT | serFRE_ERROR_BIT | serPE_ERROR_BIT ) ) != 0 )
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217 /* A PE, ORE or FRE error occurred. Clear it. */
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218 FM3_MFS0_UART->SSR |= ( 1 << 7 );
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219 cChar = FM3_MFS0_UART->RDR;
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221 else if( FM3_MFS0_UART->SSR & serRX_INT )
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223 /* A character has been received on the USART, send it to the Rx
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225 cChar = FM3_MFS0_UART->RDR;
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226 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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229 /* If sending or receiving from a queue has caused a task to unblock, and
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230 the unblocked task has a priority equal to or higher than the currently
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231 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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232 will have automatically been set to pdTRUE within the queue send or receive
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233 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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234 directly to the higher priority unblocked task. */
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235 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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237 /*-----------------------------------------------------------*/
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239 void MFS0TX_IRQHandler( void )
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241 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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244 if( FM3_MFS0_UART->SSR & serTX_INT )
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246 /* The interrupt was caused by the TX register becoming empty. Are
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247 there any more characters to transmit? */
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248 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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250 /* A character was retrieved from the queue so can be sent to the
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252 FM3_MFS0_UART->TDR = cChar;
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256 /* Disable the Tx interrupt. */
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257 FM3_MFS0_UART->SCR &= ~serTX_INT_ENABLE;
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261 /* If sending or receiving from a queue has caused a task to unblock, and
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262 the unblocked task has a priority equal to or higher than the currently
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263 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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264 will have automatically been set to pdTRUE within the queue send or receive
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265 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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266 directly to the higher priority unblocked task. */
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267 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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