mirror of https://github.com/ARMmbed/mbed-os.git
122 lines
4.1 KiB
C
122 lines
4.1 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2015, STMicroelectronics
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. Neither the name of STMicroelectronics nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stddef.h>
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#include <stdbool.h>
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#include "us_ticker_api.h"
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#include "PeripheralNames.h"
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// Timer selection
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#define TIM_MST TIM21
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static TIM_HandleTypeDef TimMasterHandle;
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static int us_ticker_inited = 0;
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volatile uint16_t SlaveCounter = 0;
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volatile uint32_t oc_int_part = 0;
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volatile uint16_t oc_rem_part = 0;
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void set_compare(uint16_t count)
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{
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TimMasterHandle.Instance = TIM_MST;
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// Set new output compare value
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__HAL_TIM_SetCompare(&TimMasterHandle, TIM_CHANNEL_1, count);
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// Enable IT
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__HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC1);
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}
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void us_ticker_init(void)
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{
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if (us_ticker_inited) return;
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us_ticker_inited = 1;
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HAL_InitTick(0); // The passed value is not used
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}
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uint32_t us_ticker_read()
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{
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volatile uint16_t cntH_old, cntH, cntL;
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if (!us_ticker_inited) us_ticker_init();
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do {
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// For some reason on L0xx series we need to read and clear the
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// overflow flag which give extra time to propelry handle possible
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// hiccup after ~60s
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if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC1OF) == SET) {
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__HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_CC1OF);
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}
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cntH_old = SlaveCounter;
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if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_UPDATE) == SET) {
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cntH_old += 1;
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}
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cntL = TIM_MST->CNT;
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cntH = SlaveCounter;
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if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_UPDATE) == SET) {
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cntH += 1;
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}
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} while(cntH_old != cntH);
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// Glue the upper and lower part together to get a 32 bit timer
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return (uint32_t)(cntH << 16 | cntL);
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}
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void us_ticker_set_interrupt(timestamp_t timestamp)
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{
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int delta = (int)((uint32_t)timestamp - us_ticker_read());
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uint16_t cval = TIM_MST->CNT;
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if (delta <= 0) { // This event was in the past
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us_ticker_irq_handler();
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} else {
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oc_int_part = (uint32_t)(delta >> 16);
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oc_rem_part = (uint16_t)(delta & 0xFFFF);
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if (oc_rem_part <= (0xFFFF - cval)) {
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set_compare(cval + oc_rem_part);
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oc_rem_part = 0;
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} else {
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set_compare(0xFFFF);
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oc_rem_part = oc_rem_part - (0xFFFF - cval);
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}
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}
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}
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void us_ticker_disable_interrupt(void)
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{
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TimMasterHandle.Instance = TIM_MST;
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__HAL_TIM_DISABLE_IT(&TimMasterHandle, TIM_IT_CC1);
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}
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void us_ticker_clear_interrupt(void)
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{
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TimMasterHandle.Instance = TIM_MST;
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if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC1) == SET) {
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__HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_CC1);
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}
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}
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