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.
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32 Note1: This driver is used specifically to provide an interface to the
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33 FreeRTOS+CLI command interpreter. It is *not* intended to be a generic
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34 serial port driver. Nor is it intended to be used as an example of an
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35 efficient implementation. In particular, a queue is used to buffer
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36 received characters, which is fine in this case as key presses arrive
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37 slowly, but a DMA and/or RAM buffer should be used in place of the queue in
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38 applications that expect higher throughput.
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40 Note2: This driver does not attempt to handle UART errors.
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43 /* Scheduler includes. */
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44 #include "FreeRTOS.h"
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49 /* Demo application includes. */
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52 /* Xilinx includes. */
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53 #include "xuartps.h"
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54 #include "xscugic.h"
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55 #include "xil_exception.h"
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57 /* The UART interrupts of interest when receiving. */
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58 #define serRECEIVE_INTERRUPT_MASK ( XUARTPS_IXR_RXOVR | XUARTPS_IXR_RXFULL | XUARTPS_IXR_TOUT )
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60 /* The UART interrupts of interest when transmitting. */
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61 #define serTRANSMIT_IINTERRUPT_MASK ( XUARTPS_IXR_TXEMPTY )
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63 /*-----------------------------------------------------------*/
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65 /* The UART being used. */
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66 static XUartPs xUARTInstance;
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68 /* The interrupt controller, which is configred by the hardware setup routines
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69 defined in main(). */
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70 extern XScuGic xInterruptController;
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72 /* The queue into which received key presses are placed. NOTE THE COMMENTS AT
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73 THE TOP OF THIS FILE REGARDING THE USE OF QUEUES FOR THIS PURPOSE. */
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74 static QueueHandle_t xRxQueue = NULL;
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76 /* The semaphore used to indicate the end of a transmission. */
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77 static SemaphoreHandle_t xTxCompleteSemaphore = NULL;
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79 /*-----------------------------------------------------------*/
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82 * The UART interrupt handler is defined in this file to provide more control,
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83 * but still uses parts of the Xilinx provided driver.
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85 void prvUART_Handler( void *pvNotUsed );
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87 /*-----------------------------------------------------------*/
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90 * See the serial2.h header file.
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92 xComPortHandle xSerialPortInitMinimal( uint32_t ulWantedBaud, UBaseType_t uxQueueLength )
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95 XUartPs_Config *pxConfig;
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97 /* Create the queue used to hold received characters. NOTE THE COMMENTS AT
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98 THE TOP OF THIS FILE REGARDING THE USE OF QUEUES FOR THIS PURPSOE. */
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99 xRxQueue = xQueueCreate( uxQueueLength, sizeof( char ) );
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100 configASSERT( xRxQueue );
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102 /* Create the semaphore used to signal the end of a transmission, then take
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103 the semaphore so it is in the correct state the first time
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104 xSerialSendString() is called. A block time of zero is used when taking
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105 the semaphore as it is guaranteed to be available (it was just created). */
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106 xTxCompleteSemaphore = xSemaphoreCreateBinary();
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107 configASSERT( xTxCompleteSemaphore );
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108 xSemaphoreTake( xTxCompleteSemaphore, 0 );
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110 /* Look up the UART configuration then initialise the dirver. */
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111 pxConfig = XUartPs_LookupConfig( XPAR_XUARTPS_0_DEVICE_ID );
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113 /* Initialise the driver. */
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114 xStatus = XUartPs_CfgInitialize( &xUARTInstance, pxConfig, XPAR_PS7_UART_1_BASEADDR );
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115 configASSERT( xStatus == XST_SUCCESS );
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116 ( void ) xStatus; /* Remove compiler warning if configASSERT() is not defined. */
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118 /* Misc. parameter configuration. */
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119 XUartPs_SetBaudRate( &xUARTInstance, ulWantedBaud );
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120 XUartPs_SetOperMode( &xUARTInstance, XUARTPS_OPER_MODE_NORMAL );
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122 /* Install the interrupt service routine that is defined within this
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124 xStatus = XScuGic_Connect( &xInterruptController, XPAR_XUARTPS_1_INTR, (Xil_ExceptionHandler) prvUART_Handler, (void *) &xUARTInstance );
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125 configASSERT( xStatus == XST_SUCCESS );
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126 ( void ) xStatus; /* Remove compiler warning if configASSERT() is not defined. */
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128 /* Ensure interrupts start clear. */
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129 XUartPs_WriteReg( XPAR_PS7_UART_1_BASEADDR, XUARTPS_ISR_OFFSET, XUARTPS_IXR_MASK );
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131 /* Enable the UART interrupt within the GIC. */
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132 XScuGic_Enable( &xInterruptController, XPAR_XUARTPS_1_INTR );
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134 /* Enable the interrupts of interest in the UART. */
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135 XUartPs_SetInterruptMask( &xUARTInstance, XUARTPS_IXR_RXFULL | XUARTPS_IXR_RXOVR | XUARTPS_IXR_TOUT | XUARTPS_IXR_TXEMPTY );
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137 /* Set the receive timeout. */
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138 XUartPs_SetRecvTimeout( &xUARTInstance, 8 );
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140 return ( xComPortHandle ) 0;
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142 /*-----------------------------------------------------------*/
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144 BaseType_t xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
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146 BaseType_t xReturn;
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148 /* Only a single port is supported. */
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151 /* Obtain a received character from the queue - entering the Blocked state
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152 (so not consuming any processing time) to wait for a character if one is not
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153 already available. */
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154 xReturn = xQueueReceive( xRxQueue, pcRxedChar, xBlockTime );
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157 /*-----------------------------------------------------------*/
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159 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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161 const TickType_t xMaxWait = 200UL / portTICK_PERIOD_MS;
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163 /* Only a single port is supported. */
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166 /* Start the transmission. The interrupt service routine will complete the
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167 transmission if necessary. */
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168 XUartPs_Send( &xUARTInstance, ( void * ) pcString, usStringLength );
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170 /* Wait until the string has been transmitted before exiting this function,
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171 otherwise there is a risk the calling function will overwrite the string
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172 pointed to by the pcString parameter while it is still being transmitted.
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173 The calling task will wait in the Blocked state (so not consuming any
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174 processing time) until the semaphore is available. */
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175 xSemaphoreTake( xTxCompleteSemaphore, xMaxWait );
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177 /*-----------------------------------------------------------*/
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179 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
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181 /* Only a single port is supported. */
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184 /* Send the character. */
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185 XUartPs_Send( &xUARTInstance, ( void * ) &cOutChar, sizeof( cOutChar ) );
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187 /* Wait for the transmission to be complete so the semaphore is left in the
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188 correct state for the next time vSerialPutString() is called. */
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189 xSemaphoreTake( xTxCompleteSemaphore, xBlockTime );
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193 /*-----------------------------------------------------------*/
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195 void vSerialClose(xComPortHandle xPort)
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197 /* Not supported as not required by the demo application. */
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200 /*-----------------------------------------------------------*/
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202 void prvUART_Handler( void *pvNotUsed )
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204 extern unsigned int XUartPs_SendBuffer( XUartPs *InstancePtr );
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205 uint32_t ulActiveInterrupts, ulChannelStatusRegister;
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206 BaseType_t xHigherPriorityTaskWoken = pdFALSE;
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209 configASSERT( pvNotUsed == &xUARTInstance );
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211 /* Remove compile warnings if configASSERT() is not defined. */
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212 ( void ) pvNotUsed;
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214 /* Read the interrupt ID register to see which interrupt is active. */
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215 ulActiveInterrupts = XUartPs_ReadReg(XPAR_PS7_UART_1_BASEADDR, XUARTPS_IMR_OFFSET);
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216 ulActiveInterrupts &= XUartPs_ReadReg(XPAR_PS7_UART_1_BASEADDR, XUARTPS_ISR_OFFSET);
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218 /* Are any receive events of interest active? */
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219 if( ( ulActiveInterrupts & serRECEIVE_INTERRUPT_MASK ) != 0 )
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221 /* Read the Channel Status Register to determine if there is any data in
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223 ulChannelStatusRegister = XUartPs_ReadReg( XPAR_PS7_UART_1_BASEADDR, XUARTPS_SR_OFFSET );
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225 /* Move data from the Rx FIFO to the Rx queue. NOTE THE COMMENTS AT THE
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226 TOP OF THIS FILE ABOUT USING QUEUES FOR THIS PURPSOE. */
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227 while( ( ulChannelStatusRegister & XUARTPS_SR_RXEMPTY ) == 0 )
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229 cChar = XUartPs_ReadReg( XPAR_PS7_UART_1_BASEADDR, XUARTPS_FIFO_OFFSET );
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231 /* If writing to the queue unblocks a task, and the unblocked task
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232 has a priority above the currently running task (the task that this
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233 interrupt interrupted), then xHigherPriorityTaskWoken will be set
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234 to pdTRUE inside the xQueueSendFromISR() function.
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235 xHigherPriorityTaskWoken is then passed to portYIELD_FROM_ISR() at
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236 the end of this interrupt handler to request a context switch so the
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237 interrupt returns directly to the (higher priority) unblocked
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239 xQueueSendFromISR( xRxQueue, &cChar, &xHigherPriorityTaskWoken );
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240 ulChannelStatusRegister = XUartPs_ReadReg( XPAR_PS7_UART_1_BASEADDR, XUARTPS_SR_OFFSET );
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244 /* Are any transmit events of interest active? */
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245 if( ( ulActiveInterrupts & serTRANSMIT_IINTERRUPT_MASK ) != 0 )
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247 if( xUARTInstance.SendBuffer.RemainingBytes == 0 )
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249 /* Give back the semaphore to indicate that the tranmission is
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250 complete. If giving the semaphore unblocks a task, and the
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251 unblocked task has a priority above the currently running task (the
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252 task that this interrupt interrupted), then xHigherPriorityTaskWoken
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253 will be set to pdTRUE inside the xSemaphoreGiveFromISR() function.
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254 xHigherPriorityTaskWoken is then passed to portYIELD_FROM_ISR() at
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255 the end of this interrupt handler to request a context switch so the
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256 interrupt returns directly to the (higher priority) unblocked
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258 xSemaphoreGiveFromISR( xTxCompleteSemaphore, &xHigherPriorityTaskWoken );
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260 /* No more data to transmit. */
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261 XUartPs_WriteReg( XPAR_PS7_UART_1_BASEADDR, XUARTPS_IDR_OFFSET, XUARTPS_IXR_TXEMPTY );
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265 /* More data to send. */
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266 XUartPs_SendBuffer( &xUARTInstance );
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270 /* portYIELD_FROM_ISR() will request a context switch if executing this
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271 interrupt handler caused a task to leave the blocked state, and the task
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272 that left the blocked state has a higher priority than the currently running
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273 task (the task this interrupt interrupted). See the comment above the calls
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274 to xSemaphoreGiveFromISR() and xQueueSendFromISR() within this function. */
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275 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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277 /* Clear the interrupt status. */
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278 XUartPs_WriteReg( XPAR_PS7_UART_1_BASEADDR, XUARTPS_ISR_OFFSET, ulActiveInterrupts );
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