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/* mbed Microcontroller Library
* Copyright (c) 2014, STMicroelectronics
* 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 of STMicroelectronics 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 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.
*/
#include <stddef.h>
#include "us_ticker_api.h"
#include "PeripheralNames.h"
// 32-bit timer selection
#define TIM_MST TIM2
#define TIM_MST_IRQ TIM2_IRQn
#define TIM_MST_RCC RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE)
static int us_ticker_inited = 0;
void us_ticker_init(void) {
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
if (us_ticker_inited) return;
us_ticker_inited = 1;
// Enable timer clock
TIM_MST_RCC;
// Configure time base
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_Period = 0xFFFFFFFF;
TIM_TimeBaseStructure.TIM_Prescaler = (uint16_t)(SystemCoreClock / 1000000) - 1; // 1 �s tick
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM_MST, &TIM_TimeBaseStructure);
NVIC_SetVector(TIM_MST_IRQ, (uint32_t)us_ticker_irq_handler);
NVIC_EnableIRQ(TIM_MST_IRQ);
// Enable timer
TIM_Cmd(TIM_MST, ENABLE);
}
uint32_t us_ticker_read() {
if (!us_ticker_inited) us_ticker_init();
return TIM_MST->CNT;
}
void us_ticker_set_interrupt(timestamp_t timestamp) {
// Set new output compare value
TIM_SetCompare1(TIM_MST, (uint32_t)timestamp);
// Enable IT
TIM_ITConfig(TIM_MST, TIM_IT_CC1, ENABLE);
}
void us_ticker_disable_interrupt(void) {
TIM_ITConfig(TIM_MST, TIM_IT_CC1, DISABLE);
}
void us_ticker_clear_interrupt(void) {
TIM_ClearITPendingBit(TIM_MST, TIM_IT_CC1);
}
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