2 FreeRTOS V9.0.0rc2 - 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 UART0.
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74 /* Standard includes. */
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77 /* Scheduler includes. */
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78 #include "FreeRTOS.h"
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81 /* Demo application includes. */
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84 /* Atmel library includes. */
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85 #include <usart/usart.h>
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86 #include <aic/aic.h>
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87 #include <pmc/pmc.h>
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89 /*-----------------------------------------------------------*/
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91 /* Location of the COM0 registers. */
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92 #define serCOM0 ( ( AT91PS_USART ) AT91C_BASE_US0 )
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94 /* Interrupt control macros. */
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95 #define serINTERRUPT_LEVEL ( 5 )
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96 #define vInterruptOn() serCOM0->US_IER = ( AT91C_US_TXRDY | AT91C_US_RXRDY )
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97 #define vInterruptOff() serCOM0->US_IDR = AT91C_US_TXRDY
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99 /* Misc constants. */
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100 #define serINVALID_QUEUE ( ( QueueHandle_t ) 0 )
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101 #define serHANDLE ( ( xComPortHandle ) 1 )
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102 #define serNO_BLOCK ( ( TickType_t ) 0 )
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103 #define serNO_TIMEGUARD ( ( unsigned long ) 0 )
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104 #define serNO_PERIPHERAL_B_SETUP ( ( unsigned long ) 0 )
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107 /* Queues used to hold received characters, and characters waiting to be
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109 static QueueHandle_t xRxedChars;
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110 static QueueHandle_t xCharsForTx;
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112 /*-----------------------------------------------------------*/
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114 /* The interrupt service routine. */
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115 __arm void vSerialISR( void );
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117 /*-----------------------------------------------------------*/
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120 * See the serial2.h header file.
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122 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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124 xComPortHandle xReturn = serHANDLE;
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126 /* Create the queues used to hold Rx and Tx characters. */
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127 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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128 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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130 /* If the queues were created correctly then setup the serial port
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132 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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134 PMC_EnablePeripheral( AT91C_ID_US0 );
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135 portENTER_CRITICAL();
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137 USART_Configure( serCOM0, ( AT91C_US_CHRL_8_BITS | AT91C_US_PAR_NONE ), ulWantedBaud, configCPU_CLOCK_HZ );
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139 /* Enable Rx and Tx. */
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140 USART_SetTransmitterEnabled( serCOM0, pdTRUE );
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141 USART_SetReceiverEnabled( serCOM0, pdTRUE );
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143 /* Enable the Rx interrupts. The Tx interrupts are not enabled
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144 until there are characters to be transmitted. */
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145 serCOM0->US_IER = AT91C_US_RXRDY;
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147 /* Enable the interrupts in the AIC. */
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148 AIC_ConfigureIT( AT91C_ID_US0, AT91C_AIC_PRIOR_LOWEST, ( void (*)( void ) ) vSerialISR );
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149 AIC_EnableIT( AT91C_ID_US0 );
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151 portEXIT_CRITICAL();
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155 xReturn = ( xComPortHandle ) 0;
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158 /* This demo file only supports a single port but we have to return
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159 something to comply with the standard demo header file. */
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162 /*-----------------------------------------------------------*/
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164 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
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166 /* The port handle is not required as this driver only supports one port. */
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169 /* Get the next character from the buffer. Return false if no characters
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170 are available, or arrive before xBlockTime expires. */
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171 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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180 /*-----------------------------------------------------------*/
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182 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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184 signed char *pxNext;
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186 /* A couple of parameters that this port does not use. */
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187 ( void ) usStringLength;
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190 /* NOTE: This implementation does not handle the queue being full as no
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191 block time is used! */
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193 /* The port handle is not required as this driver only supports UART0. */
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196 /* Send each character in the string, one at a time. */
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197 pxNext = ( signed char * ) pcString;
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200 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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204 /*-----------------------------------------------------------*/
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206 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
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208 /* Just to remove compiler warning. */
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211 /* Place the character in the queue of characters to be transmitted. */
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212 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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217 /* Turn on the Tx interrupt so the ISR will remove the character from the
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218 queue and send it. This does not need to be in a critical section as
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219 if the interrupt has already removed the character the next interrupt
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220 will simply turn off the Tx interrupt again. */
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225 /*-----------------------------------------------------------*/
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227 void vSerialClose( xComPortHandle xPort )
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229 /* Not supported as not required by the demo application. */
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232 /*-----------------------------------------------------------*/
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234 /* Serial port ISR. This can cause a context switch so is not defined as a
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235 standard ISR using the __irq keyword. Instead a wrapper function is defined
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236 within serialISR.s79 which in turn calls this function. See the port
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237 documentation on the FreeRTOS.org website for more information. */
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238 __arm void vSerialISR( void )
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240 unsigned long ulStatus;
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242 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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244 /* What caused the interrupt? */
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245 ulStatus = serCOM0->US_CSR &= serCOM0->US_IMR;
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247 if( ulStatus & AT91C_US_TXRDY )
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249 /* The interrupt was caused by the THR becoming empty. Are there any
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250 more characters to transmit? */
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251 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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253 /* A character was retrieved from the queue so can be sent to the
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255 serCOM0->US_THR = cChar;
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259 /* Queue empty, nothing to send so turn off the Tx interrupt. */
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264 if( ulStatus & AT91C_US_RXRDY )
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266 /* The interrupt was caused by a character being received. Grab the
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267 character from the RHR and place it in the queue or received
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269 cChar = serCOM0->US_RHR;
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270 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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273 /* If a task was woken by either a character being received or a character
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274 being transmitted then we may need to switch to another task. */
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275 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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277 /* End the interrupt in the AIC. */
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278 AT91C_BASE_AIC->AIC_EOICR = 0;
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