stm8s_delay.c

/*
 * This file is provided under a MIT license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * MIT License
 *
 * Copyright (c) 2020 Pavel Nadein
 *
 * 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.
 *
 * 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.
 *
 * STM8S open source driver
 *
 * Contact Information:
 * Pavel Nadein <pavelnadein@gmail.com>
 */

#include "stm8s_delay.h"
#include "stm8s_clk.h"

/**
  * @brief  Init TIM4 to be used for delay functions.
  * @retval none
  */
void delays_init(void)
{
	CLK->PCKENR1 |= CLK_PCKENR1_TIM4;
	TIM4->PSCR = 4 / ((CLK->CKDIVR >> 3) & 3);
	TIM4->EGR |= TIM4_EGR_UG;
	TIM4->SR1 = 0;
	TIM4->CR1 = TIM4_CR1_CEN;
}

/**
  * @brief  Wait us microseconds
  * @param  us: amount of microseconds to wait
  * @retval none
  */
void delay_us(u8 us)
{
	TIM4->CNTR = 0;
	while (TIM4->CNTR < us);
}

/**
  * @brief  Wait us milliseconds
  * @param  us: amount of milliseconds to wait
  * @retval none
  */
void delay_ms(u16 ms)
{
	ms = ms << 2;
	while (ms--) delay_us(250);
}