1 /* mbed Microcontroller Library
2 * Copyright (c) 2014, STMicroelectronics
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
8 * 1. Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 * this list of conditions and the following disclaimer in the documentation
12 * and/or other materials provided with the distribution.
13 * 3. Neither the name of STMicroelectronics nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
24 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 #include "us_ticker_api.h"
30 #include "PeripheralNames.h"
32 // 32-bit timer selection
34 #define TIM_MST_IRQ TIM2_IRQn
35 #define TIM_MST_RCC RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE)
37 static int us_ticker_inited = 0;
39 void us_ticker_init(void) {
40 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
42 if (us_ticker_inited) return;
48 // Configure time base
49 TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
50 TIM_TimeBaseStructure.TIM_Period = 0xFFFFFFFF;
51 TIM_TimeBaseStructure.TIM_Prescaler = (uint16_t)(SystemCoreClock / 1000000) - 1; // 1 �s tick
52 TIM_TimeBaseStructure.TIM_ClockDivision = 0;
53 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
54 TIM_TimeBaseInit(TIM_MST, &TIM_TimeBaseStructure);
56 NVIC_SetVector(TIM_MST_IRQ, (uint32_t)us_ticker_irq_handler);
57 NVIC_EnableIRQ(TIM_MST_IRQ);
60 TIM_Cmd(TIM_MST, ENABLE);
63 uint32_t us_ticker_read() {
64 if (!us_ticker_inited) us_ticker_init();
68 void us_ticker_set_interrupt(timestamp_t timestamp) {
69 // Set new output compare value
70 TIM_SetCompare1(TIM_MST, (uint32_t)timestamp);
72 TIM_ITConfig(TIM_MST, TIM_IT_CC1, ENABLE);
75 void us_ticker_disable_interrupt(void) {
76 TIM_ITConfig(TIM_MST, TIM_IT_CC1, DISABLE);
79 void us_ticker_clear_interrupt(void) {
80 TIM_ClearITPendingBit(TIM_MST, TIM_IT_CC1);