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136 lines
3.8 KiB
C
136 lines
3.8 KiB
C
/**************************************************************************/
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/*!
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@file systick.c
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@author K. Townsend (microBuilder.eu)
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@date 22 March 2010
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@version 0.10
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@section DESCRIPTION
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Controls the 24-bit 'system tick' clock, which can be used as a
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generic timer or to control time sharing with an embedded real-time
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operating system (such as FreeRTOS).
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@section Example
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@code
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#include "core/cpu/cpu.h"
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#include "core/systick/systick.h"
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void main (void)
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{
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cpuInit();
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// Start systick timer with one tick every 10ms
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systickInit(10);
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while(1)
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{
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}
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}
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@endcode
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@section LICENSE
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Software License Agreement (BSD License)
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Copyright (c) 2010, microBuilder SARL
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. Neither the name of the copyright holders nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**************************************************************************/
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#include "systick.h"
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#ifdef CFG_SDCARD
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#include "drivers/fatfs/diskio.h"
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volatile uint32_t fatTicks = 0;
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#endif
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volatile uint32_t msTicks; // 1ms tick counter
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void SysTick_Handler (void)
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{
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msTicks++;
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#ifdef CFG_SDCARD
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fatTicks++;
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if (fatTicks == 10)
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{
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fatTicks = 0;
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disk_timerproc();
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}
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#endif
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}
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static uint32_t systickConfig(uint32_t ticks)
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{
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// Check if 'ticks' is greater than maximum value
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if (ticks > SYSTICK_STRELOAD_MASK)
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{
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return (1);
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}
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// Set reload register
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SYSTICK_STRELOAD = (ticks & SYSTICK_STRELOAD_MASK) - 1;
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// Load the systick counter value
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SYSTICK_STCURR = 0;
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// Enable systick IRQ and timer
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SYSTICK_STCTRL = SYSTICK_STCTRL_CLKSOURCE |
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SYSTICK_STCTRL_TICKINT |
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SYSTICK_STCTRL_ENABLE;
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return (0);
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}
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void systickInit (uint32_t delayMs)
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{
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systickConfig ((CFG_CPU_CCLK / 1000) * delayMs);
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}
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void systickDelay (uint32_t delayTicks)
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{
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uint32_t curTicks;
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curTicks = msTicks;
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// Make sure delay is at least 1 tick in case of division, etc.
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if (delayTicks == 0) delayTicks = 1;
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if (curTicks > 0x00FFFFFF - delayTicks)
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{
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// Rollover will occur during delay
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while (msTicks >= curTicks)
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{
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while (msTicks < (delayTicks - (0x00FFFFFF - curTicks)));
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}
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}
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else
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{
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while ((msTicks - curTicks) < delayTicks);
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}
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}
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