free-dap/platform/same70/timer.c
2020-02-23 14:50:09 -08:00

125 lines
3.6 KiB
C

/*
* Copyright (c) 2020, Alex Taradov <alex@taradov.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*- Includes ----------------------------------------------------------------*/
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include "same70.h"
#include "timer.h"
/*- Variables ---------------------------------------------------------------*/
static Timer *g_timer_list[TIMER_COUNT];
/*- Implementations ---------------------------------------------------------*/
//-----------------------------------------------------------------------------
static inline void systick_start(void)
{
SysTick->CTRL = SysTick_CTRL_ENABLE_Msk | SysTick_CTRL_TICKINT_Msk;
}
//-----------------------------------------------------------------------------
static inline void systick_stop(void)
{
SysTick->CTRL = 0;
}
//-----------------------------------------------------------------------------
void timer_init(void)
{
SysTick->VAL = 0;
SysTick->LOAD = (F_CPU / 1000) * TIMER_TICK;
for (int i = 0; i < TIMER_COUNT; i++)
g_timer_list[i] = NULL;
systick_start();
}
//-----------------------------------------------------------------------------
void timer_start(Timer *timer)
{
timer->expired = false;
timer->interval = (timer->interval < TIMER_TICK) ? TIMER_TICK : timer->interval;
timer->timeout = timer->interval / TIMER_TICK;
systick_stop();
for (int i = 0; i < TIMER_COUNT; i++)
{
if (g_timer_list[i] == NULL)
{
g_timer_list[i] = timer;
break;
}
}
systick_start();
}
//-----------------------------------------------------------------------------
void timer_stop(Timer *timer)
{
systick_stop();
for (int i = 0; i < TIMER_COUNT; i++)
{
if (g_timer_list[i] == timer)
{
g_timer_list[i] = NULL;
break;
}
}
systick_start();
}
//-----------------------------------------------------------------------------
void irq_handler_sys_tick(void)
{
for (int i = 0; i < TIMER_COUNT; i++)
{
Timer *timer = g_timer_list[i];
if (timer == NULL)
continue;
if (--timer->timeout > 0)
continue;
timer->expired = true;
if (timer->repeat)
timer->timeout = timer->interval / TIMER_TICK;
else
g_timer_list[i] = NULL;
}
}