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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Source/] [portable/] [WizC/] [PIC18/] [Drivers/] [Tick/] [Tick.c] - Blame information for rev 572

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1 572 jeremybenn
/*
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    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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    ***************************************************************************
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    *                                                                         *
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    * If you are:                                                             *
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    *                                                                         *
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    *    + New to FreeRTOS,                                                   *
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    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
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    *    + Looking for basic training,                                        *
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    *    + Wanting to improve your FreeRTOS skills and productivity           *
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    *                                                                         *
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    * then take a look at the FreeRTOS books - available as PDF or paperback  *
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    *                                                                         *
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    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
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    *                  http://www.FreeRTOS.org/Documentation                  *
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    *                                                                         *
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    * A pdf reference manual is also available.  Both are usually delivered   *
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    * to your inbox within 20 minutes to two hours when purchased between 8am *
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    * and 8pm GMT (although please allow up to 24 hours in case of            *
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    * exceptional circumstances).  Thank you for your support!                *
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    *                                                                         *
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    ***************************************************************************
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    This file is part of the FreeRTOS distribution.
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    FreeRTOS is free software; you can redistribute it and/or modify it under
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    the terms of the GNU General Public License (version 2) as published by the
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    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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    ***NOTE*** The exception to the GPL is included to allow you to distribute
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    a combined work that includes FreeRTOS without being obliged to provide the
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    source code for proprietary components outside of the FreeRTOS kernel.
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    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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    more details. You should have received a copy of the GNU General Public
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    License and the FreeRTOS license exception along with FreeRTOS; if not it
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    can be viewed here: http://www.freertos.org/a00114.html and also obtained
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    by writing to Richard Barry, contact details for whom are available on the
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    FreeRTOS WEB site.
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    1 tab == 4 spaces!
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    http://www.FreeRTOS.org - Documentation, latest information, license and
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    contact details.
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    http://www.SafeRTOS.com - A version that is certified for use in safety
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    critical systems.
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    http://www.OpenRTOS.com - Commercial support, development, porting,
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    licensing and training services.
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*/
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/*
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Changes from V3.0.0
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        + ISRcode is pulled inline and portTICKisr() is therefore
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          deleted from this file.
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        + Prescaler logic for Timer1 added to allow for a wider
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          range of TickRates.
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Changes from V3.0.1
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*/
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#include <FreeRTOS.h>
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#include <task.h>
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/* IO port constants. */
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#define portBIT_SET             (1)
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#define portBIT_CLEAR   (0)
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/*
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 * Hardware setup for the tick.
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 * We use a compare match on timer1. Depending on MPU-frequency
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 * and requested tickrate, a prescaled value with a matching
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 * prescaler are determined.
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 */
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#define portTIMER_COMPARE_BASE                  ((APROCFREQ/4)/configTICK_RATE_HZ)
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#if portTIMER_COMPARE_BASE   < 0x10000
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        #define portTIMER_COMPARE_VALUE         (portTIMER_COMPARE_BASE)
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        #define portTIMER_COMPARE_PS1           (portBIT_CLEAR)
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        #define portTIMER_COMPARE_PS0           (portBIT_CLEAR)
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#elif portTIMER_COMPARE_BASE < 0x20000
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        #define portTIMER_COMPARE_VALUE         (portTIMER_COMPARE_BASE / 2)
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        #define portTIMER_COMPARE_PS1           (portBIT_CLEAR)
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        #define portTIMER_COMPARE_PS0           (portBIT_SET)
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#elif portTIMER_COMPARE_BASE < 0x40000
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        #define portTIMER_COMPARE_VALUE         (portTIMER_COMPARE_BASE / 4)
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        #define portTIMER_COMPARE_PS1           (portBIT_SET)
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        #define portTIMER_COMPARE_PS0           (portBIT_CLEAR)
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#elif portTIMER_COMPARE_BASE < 0x80000
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        #define portTIMER_COMPARE_VALUE         (portTIMER_COMPARE_BASE / 8)
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        #define portTIMER_COMPARE_PS1           (portBIT_SET)
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        #define portTIMER_COMPARE_PS0           (portBIT_SET)
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#else
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        #error "TickRate out of range"
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#endif
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/*-----------------------------------------------------------*/
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/*
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 * Setup a timer for a regular tick.
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 */
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void portSetupTick( void )
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{
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        /*
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         * Interrupts are disabled when this function is called.
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         */
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        /*
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         * Setup CCP1
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         * Provide the tick interrupt using a compare match on timer1.
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         */
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        /*
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         * Set the compare match value.
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         */
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        CCPR1H = ( unsigned char ) ( ( portTIMER_COMPARE_VALUE >> 8 ) & 0xff );
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        CCPR1L = ( unsigned char )   ( portTIMER_COMPARE_VALUE & 0xff );
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        /*
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         * Set Compare Special Event Trigger Mode
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         */
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        bCCP1M3         = portBIT_SET;
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        bCCP1M2         = portBIT_CLEAR;
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        bCCP1M1         = portBIT_SET;
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        bCCP1M0         = portBIT_SET;
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        /*
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         * Enable CCP1 interrupt
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         */
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        bCCP1IE         = portBIT_SET;
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        /*
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         * We are only going to use the global interrupt bit, so disable
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         * interruptpriorities and enable peripheral interrupts.
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         */
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        bIPEN           = portBIT_CLEAR;
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        bPEIE           = portBIT_SET;
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        /*
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         * Set up timer1
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         * It will produce the system tick.
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         */
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        /*
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         * Clear the time count
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         */
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        TMR1H = ( unsigned char ) 0x00;
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        TMR1L = ( unsigned char ) 0x00;
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        /*
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         * Setup the timer
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         */
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        bRD16           = portBIT_SET;                          // 16-bit
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        bT1CKPS1        = portTIMER_COMPARE_PS1;        // prescaler
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        bT1CKPS0        = portTIMER_COMPARE_PS0;        // prescaler
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        bT1OSCEN        = portBIT_SET;                          // Oscillator enable
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        bT1SYNC         = portBIT_SET;                          // No external clock sync
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        bTMR1CS         = portBIT_CLEAR;                        // Internal clock
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        bTMR1ON         = portBIT_SET;                          // Start timer1
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}

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