b luo / mbed-dev

mbed library sources. With a patch for the can_api

Fork of mbed-dev by mbed official

targets/TARGET_STM/TARGET_STM32F1/us_ticker.c@151:91825d030f9b, 2016-11-14 (annotated)

Committer:
DangerousElectrician
Date:
Mon Nov 14 04:39:23 2016 +0000
Revision:
151:91825d030f9b
Parent:
150:02e0a0aed4ec 
stuff changed?

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /* mbed Microcontroller Library
<> 144:ef7eb2e8f9f7 2 * Copyright (c) 2014, STMicroelectronics
<> 144:ef7eb2e8f9f7 3 * All rights reserved.
<> 144:ef7eb2e8f9f7 4 *
<> 144:ef7eb2e8f9f7 5 * Redistribution and use in source and binary forms, with or without
<> 144:ef7eb2e8f9f7 6 * modification, are permitted provided that the following conditions are met:
<> 144:ef7eb2e8f9f7 7 *
<> 144:ef7eb2e8f9f7 8 * 1. Redistributions of source code must retain the above copyright notice,
<> 144:ef7eb2e8f9f7 9 * this list of conditions and the following disclaimer.
<> 144:ef7eb2e8f9f7 10 * 2. Redistributions in binary form must reproduce the above copyright notice,
<> 144:ef7eb2e8f9f7 11 * this list of conditions and the following disclaimer in the documentation
<> 144:ef7eb2e8f9f7 12 * and/or other materials provided with the distribution.
<> 144:ef7eb2e8f9f7 13 * 3. Neither the name of STMicroelectronics nor the names of its contributors
<> 144:ef7eb2e8f9f7 14 * may be used to endorse or promote products derived from this software
<> 144:ef7eb2e8f9f7 15 * without specific prior written permission.
<> 144:ef7eb2e8f9f7 16 *
<> 144:ef7eb2e8f9f7 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
<> 144:ef7eb2e8f9f7 18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
<> 144:ef7eb2e8f9f7 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
<> 144:ef7eb2e8f9f7 20 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
<> 144:ef7eb2e8f9f7 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
<> 144:ef7eb2e8f9f7 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
<> 144:ef7eb2e8f9f7 23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
<> 144:ef7eb2e8f9f7 24 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
<> 144:ef7eb2e8f9f7 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
<> 144:ef7eb2e8f9f7 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
<> 144:ef7eb2e8f9f7 27 */
<> 144:ef7eb2e8f9f7 28 #include <stddef.h>
<> 144:ef7eb2e8f9f7 29 #include "us_ticker_api.h"
<> 144:ef7eb2e8f9f7 30 #include "PeripheralNames.h"
<> 144:ef7eb2e8f9f7 31
<> 144:ef7eb2e8f9f7 32 // Timer selection
<> 144:ef7eb2e8f9f7 33 #define TIM_MST TIM4
<> 144:ef7eb2e8f9f7 34
<> 144:ef7eb2e8f9f7 35 static TIM_HandleTypeDef TimMasterHandle;
<> 144:ef7eb2e8f9f7 36 static int us_ticker_inited = 0;
<> 144:ef7eb2e8f9f7 37
<> 144:ef7eb2e8f9f7 38 volatile uint32_t SlaveCounter = 0;
<> 144:ef7eb2e8f9f7 39 volatile uint32_t oc_int_part = 0;
<> 144:ef7eb2e8f9f7 40 volatile uint16_t oc_rem_part = 0;
<> 144:ef7eb2e8f9f7 41
<> 144:ef7eb2e8f9f7 42 void set_compare(uint16_t count)
<> 144:ef7eb2e8f9f7 43 {
<> 144:ef7eb2e8f9f7 44 TimMasterHandle.Instance = TIM_MST;
<> 144:ef7eb2e8f9f7 45 // Set new output compare value
<> 144:ef7eb2e8f9f7 46 __HAL_TIM_SetCompare(&TimMasterHandle, TIM_CHANNEL_1, count);
<> 144:ef7eb2e8f9f7 47 // Enable IT
<> 144:ef7eb2e8f9f7 48 __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC1);
<> 144:ef7eb2e8f9f7 49 }
<> 144:ef7eb2e8f9f7 50
<> 144:ef7eb2e8f9f7 51 void us_ticker_init(void)
<> 144:ef7eb2e8f9f7 52 {
<> 144:ef7eb2e8f9f7 53 if (us_ticker_inited) return;
<> 144:ef7eb2e8f9f7 54 us_ticker_inited = 1;
<> 144:ef7eb2e8f9f7 55
<> 144:ef7eb2e8f9f7 56 HAL_InitTick(0); // The passed value is not used
<> 144:ef7eb2e8f9f7 57 }
<> 144:ef7eb2e8f9f7 58
<> 144:ef7eb2e8f9f7 59 uint32_t us_ticker_read()
<> 144:ef7eb2e8f9f7 60 {
<> 150:02e0a0aed4ec 61 uint32_t counter, counter2;
<> 144:ef7eb2e8f9f7 62 if (!us_ticker_inited) us_ticker_init();
<> 150:02e0a0aed4ec 63 // A situation might appear when Master overflows right after Slave is read and before the
<> 150:02e0a0aed4ec 64 // new (overflowed) value of Master is read. Which would make the code below consider the
<> 150:02e0a0aed4ec 65 // previous (incorrect) value of Slave and the new value of Master, which would return a
<> 150:02e0a0aed4ec 66 // value in the past. Avoid this by computing consecutive values of the timer until they
<> 150:02e0a0aed4ec 67 // are properly ordered.
<> 144:ef7eb2e8f9f7 68 counter = (uint32_t)(SlaveCounter << 16);
<> 150:02e0a0aed4ec 69 counter += TIM_MST->CNT;
<> 150:02e0a0aed4ec 70 while (1) {
<> 150:02e0a0aed4ec 71 counter2 = (uint32_t)(SlaveCounter << 16);
<> 150:02e0a0aed4ec 72 counter2 += TIM_MST->CNT;
<> 150:02e0a0aed4ec 73 if (counter2 > counter) {
<> 150:02e0a0aed4ec 74 break;
<> 150:02e0a0aed4ec 75 }
<> 150:02e0a0aed4ec 76 counter = counter2;
<> 150:02e0a0aed4ec 77 }
<> 150:02e0a0aed4ec 78 return counter2;
<> 144:ef7eb2e8f9f7 79 }
<> 144:ef7eb2e8f9f7 80
<> 144:ef7eb2e8f9f7 81 void us_ticker_set_interrupt(timestamp_t timestamp)
<> 144:ef7eb2e8f9f7 82 {
<> 144:ef7eb2e8f9f7 83 int delta = (int)((uint32_t)timestamp - us_ticker_read());
<> 144:ef7eb2e8f9f7 84 uint16_t cval = TIM_MST->CNT;
<> 144:ef7eb2e8f9f7 85
<> 144:ef7eb2e8f9f7 86 if (delta <= 0) { // This event was in the past
<> 144:ef7eb2e8f9f7 87 us_ticker_irq_handler();
<> 144:ef7eb2e8f9f7 88 } else {
<> 144:ef7eb2e8f9f7 89 oc_int_part = (uint32_t)(delta >> 16);
<> 144:ef7eb2e8f9f7 90 oc_rem_part = (uint16_t)(delta & 0xFFFF);
<> 144:ef7eb2e8f9f7 91 if (oc_rem_part <= (0xFFFF - cval)) {
<> 144:ef7eb2e8f9f7 92 set_compare(cval + oc_rem_part);
<> 144:ef7eb2e8f9f7 93 oc_rem_part = 0;
<> 144:ef7eb2e8f9f7 94 } else {
<> 144:ef7eb2e8f9f7 95 set_compare(0xFFFF);
<> 144:ef7eb2e8f9f7 96 oc_rem_part = oc_rem_part - (0xFFFF - cval);
<> 144:ef7eb2e8f9f7 97 }
<> 144:ef7eb2e8f9f7 98 }
<> 144:ef7eb2e8f9f7 99 }
<> 144:ef7eb2e8f9f7 100
<> 144:ef7eb2e8f9f7 101 void us_ticker_disable_interrupt(void)
<> 144:ef7eb2e8f9f7 102 {
<> 144:ef7eb2e8f9f7 103 TimMasterHandle.Instance = TIM_MST;
<> 144:ef7eb2e8f9f7 104 __HAL_TIM_DISABLE_IT(&TimMasterHandle, TIM_IT_CC1);
<> 144:ef7eb2e8f9f7 105 }
<> 144:ef7eb2e8f9f7 106
<> 144:ef7eb2e8f9f7 107 void us_ticker_clear_interrupt(void)
<> 144:ef7eb2e8f9f7 108 {
<> 144:ef7eb2e8f9f7 109 TimMasterHandle.Instance = TIM_MST;
<> 144:ef7eb2e8f9f7 110 if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC1) == SET) {
<> 144:ef7eb2e8f9f7 111 __HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_CC1);
<> 144:ef7eb2e8f9f7 112 }
<> 144:ef7eb2e8f9f7 113 }