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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29 /* FreeRTOS includes. */
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30 #include "FreeRTOS.h"
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33 /* Library includes. */
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37 * The FreeRTOS tick handler. This function must be installed as the handler
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38 * for the timer used to generate the tick interrupt. Note that the interrupt
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39 * generated by the PIT is shared by other system peripherals, so if the PIT is
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40 * used for Tick generation then FreeRTOS_Tick_Handler() can only be installed
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41 * directly as the PIT handler if no other system interrupts need to be
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42 * serviced. If system interrupts other than the PIT need to be serviced then
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43 * install System_Handler() as the PIT interrupt handler in place of
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44 * FreeRTOS_Tick_Handler() and add additional interrupt processing into the
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45 * implementation of System_Handler().
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47 extern void FreeRTOS_Tick_Handler( void );
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48 static void System_Handler( void );
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50 /*-----------------------------------------------------------*/
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52 static void System_Handler( void )
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54 /* See the comments above the function prototype in this file. */
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55 FreeRTOS_Tick_Handler();
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57 /*-----------------------------------------------------------*/
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60 * The application must provide a function that configures a peripheral to
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61 * create the FreeRTOS tick interrupt, then define configSETUP_TICK_INTERRUPT()
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62 * in FreeRTOSConfig.h to call the function. This file contains a function
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63 * that is suitable for use on the Atmel SAMA5.
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65 void vConfigureTickInterrupt( void )
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67 /* NOTE: The PIT interrupt is cleared by the configCLEAR_TICK_INTERRUPT()
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68 macro in FreeRTOSConfig.h. */
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70 /* Enable the PIT clock. */
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71 PMC->PMC_PCER0 = 1 << ID_PIT;
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73 /* Initialize the PIT to the desired frequency - specified in uS. */
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74 PIT_Init( 1000000UL / configTICK_RATE_HZ, ( BOARD_MCK / 2 ) / 1000000 );
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76 /* Enable IRQ / select PIT interrupt. */
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77 PMC->PMC_PCER1 = ( 1 << ( ID_IRQ - 32 ) );
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78 AIC->AIC_SSR = ID_PIT;
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80 /* Ensure interrupt is disabled before setting the mode and installing the
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81 handler. The priority of the tick interrupt should always be set to the
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83 AIC->AIC_IDCR = AIC_IDCR_INTD;
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84 AIC->AIC_SMR = AIC_SMR_SRCTYPE_EXT_POSITIVE_EDGE;
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85 AIC->AIC_SVR = ( uint32_t ) FreeRTOS_Tick_Handler;
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87 /* Start with the interrupt clear. */
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88 AIC->AIC_ICCR = AIC_ICCR_INTCLR;
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90 /* Enable the interrupt in the AIC and peripheral. */
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91 AIC_EnableIT( ID_PIT );
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94 /* Enable the peripheral. */
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97 /* Prevent compiler warnings in the case where System_Handler() is not used
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98 as the handler. See the comments above the System_Handler() function
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99 prototype at the top of this file. */
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100 ( void ) System_Handler;
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102 /*-----------------------------------------------------------*/
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