systick.c
2.75 KB
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/****************************************************************************
*
* Copyright (c) 2019 PX4 Development Team. 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. Neither the name PX4 nor the names of its contributors may 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 OWNER 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.
*
****************************************************************************/
#include "arm_arch.h"
#include "systick.h"
#include <nvic.h>
uint8_t systick_get_countflag(void)
{
return (getreg32(NVIC_SYSTICK_CTRL) & NVIC_SYSTICK_CTRL_COUNTFLAG) ? 1 : 0;
}
// See 2.2.3 SysTick external clock is not HCLK/8
uint32_t g_divisor = 1;
void systick_set_reload(uint32_t value)
{
putreg32((((value * g_divisor) << NVIC_SYSTICK_RELOAD_SHIFT) & NVIC_SYSTICK_RELOAD_MASK), NVIC_SYSTICK_RELOAD);
}
void systick_set_clocksource(uint8_t clocksource)
{
g_divisor = (clocksource == CLKSOURCE_EXTERNAL) ? 8 : 1;
modifyreg32(NVIC_SYSTICK_CTRL, NVIC_SYSTICK_CTRL_CLKSOURCE, clocksource & NVIC_SYSTICK_CTRL_CLKSOURCE);
}
void systick_counter_enable(void)
{
modifyreg32(NVIC_SYSTICK_CTRL, 0, NVIC_SYSTICK_CTRL_ENABLE);
}
void systick_counter_disable(void)
{
modifyreg32(NVIC_SYSTICK_CTRL, NVIC_SYSTICK_CTRL_ENABLE, 0);
putreg32(0, NVIC_SYSTICK_CURRENT);
}
void systick_interrupt_enable(void)
{
modifyreg32(NVIC_SYSTICK_CTRL, 0, NVIC_SYSTICK_CTRL_TICKINT);
}
void systick_interrupt_disable(void)
{
modifyreg32(NVIC_SYSTICK_CTRL, NVIC_SYSTICK_CTRL_TICKINT, 0);
}