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/*
* FreeRTOS Kernel V10.2.1
* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/*
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 = ( uint8_t ) ( ( portTIMER_COMPARE_VALUE >> 8 ) & 0xff );
CCPR1L = ( uint8_t ) ( 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 = ( uint8_t ) 0x00;
TMR1L = ( uint8_t ) 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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