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/*
FreeRTOS.org V4.1.0 - Copyright (C) 2003-2006 Richard Barry.
This file is part of the FreeRTOS.org distribution.
FreeRTOS.org is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FreeRTOS.org is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FreeRTOS.org; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes FreeRTOS.org, without being obliged to provide
the source code for any proprietary components. See the licensing section
of http://www.FreeRTOS.org for full details of how and when the exception
can be applied.
***************************************************************************
See http://www.FreeRTOS.org for documentation, latest information, license
and contact details. Please ensure to read the configuration and relevant
port sections of the online documentation.
***************************************************************************
*/
/*
Changes from V3.0.0
+ ISRcode is pulled inline and portTICKisr() is therefore
deleted from this file.
+ Prescaler logic for Timer1 added to allow for a wider
range of TickRates.
Changes from V3.0.1
*/
#include <FreeRTOS.h>
#include <task.h>
/* IO port constants. */
#define portBIT_SET (1)
#define portBIT_CLEAR (0)
/*
* Hardware setup for the tick.
* We use a compare match on timer1. Depending on MPU-frequency
* and requested tickrate, a prescaled value with a matching
* prescaler are determined.
*/
#define portTIMER_COMPARE_BASE ((APROCFREQ/4)/configTICK_RATE_HZ)
#if portTIMER_COMPARE_BASE < 0x10000
#define portTIMER_COMPARE_VALUE (portTIMER_COMPARE_BASE)
#define portTIMER_COMPARE_PS1 (portBIT_CLEAR)
#define portTIMER_COMPARE_PS0 (portBIT_CLEAR)
#elif portTIMER_COMPARE_BASE < 0x20000
#define portTIMER_COMPARE_VALUE (portTIMER_COMPARE_BASE / 2)
#define portTIMER_COMPARE_PS1 (portBIT_CLEAR)
#define portTIMER_COMPARE_PS0 (portBIT_SET)
#elif portTIMER_COMPARE_BASE < 0x40000
#define portTIMER_COMPARE_VALUE (portTIMER_COMPARE_BASE / 4)
#define portTIMER_COMPARE_PS1 (portBIT_SET)
#define portTIMER_COMPARE_PS0 (portBIT_CLEAR)
#elif portTIMER_COMPARE_BASE < 0x80000
#define portTIMER_COMPARE_VALUE (portTIMER_COMPARE_BASE / 8)
#define portTIMER_COMPARE_PS1 (portBIT_SET)
#define portTIMER_COMPARE_PS0 (portBIT_SET)
#else
#error "TickRate out of range"
#endif
/*-----------------------------------------------------------*/
/*
* Setup a timer for a regular tick.
*/
void portSetupTick( void )
{
/*
* Interrupts are disabled when this function is called.
*/
/*
* Setup CCP1
* Provide the tick interrupt using a compare match on timer1.
*/
/*
* Set the compare match value.
*/
CCPR1H = ( unsigned portCHAR ) ( ( portTIMER_COMPARE_VALUE >> 8 ) & 0xff );
CCPR1L = ( unsigned portCHAR ) ( portTIMER_COMPARE_VALUE & 0xff );
/*
* Set Compare Special Event Trigger Mode
*/
bCCP1M3 = portBIT_SET;
bCCP1M2 = portBIT_CLEAR;
bCCP1M1 = portBIT_SET;
bCCP1M0 = portBIT_SET;
/*
* Enable CCP1 interrupt
*/
bCCP1IE = portBIT_SET;
/*
* We are only going to use the global interrupt bit, so disable
* interruptpriorities and enable peripheral interrupts.
*/
bIPEN = portBIT_CLEAR;
bPEIE = portBIT_SET;
/*
* Set up timer1
* It will produce the system tick.
*/
/*
* Clear the time count
*/
TMR1H = ( unsigned portCHAR ) 0x00;
TMR1L = ( unsigned portCHAR ) 0x00;
/*
* Setup the timer
*/
bRD16 = portBIT_SET; // 16-bit
bT1CKPS1 = portTIMER_COMPARE_PS1; // prescaler
bT1CKPS0 = portTIMER_COMPARE_PS0; // prescaler
bT1OSCEN = portBIT_SET; // Oscillator enable
bT1SYNC = portBIT_SET; // No external clock sync
bTMR1CS = portBIT_CLEAR; // Internal clock
bTMR1ON = portBIT_SET; // Start timer1
}
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