teralytic / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed by teralytic

targets/hal/TARGET_STM/TARGET_STM32L0/us_ticker.c@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
Child:
136:5728e9819171
Initial commit on mbed-dev



Replaces mbed-src (now inactive)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 0:9b334a45a8ff 1 /* mbed Microcontroller Library
bogdanm 0:9b334a45a8ff 2 * Copyright (c) 2015, STMicroelectronics
bogdanm 0:9b334a45a8ff 3 * All rights reserved.
bogdanm 0:9b334a45a8ff 4 *
bogdanm 0:9b334a45a8ff 5 * Redistribution and use in source and binary forms, with or without
bogdanm 0:9b334a45a8ff 6 * modification, are permitted provided that the following conditions are met:
bogdanm 0:9b334a45a8ff 7 *
bogdanm 0:9b334a45a8ff 8 * 1. Redistributions of source code must retain the above copyright notice,
bogdanm 0:9b334a45a8ff 9 * this list of conditions and the following disclaimer.
bogdanm 0:9b334a45a8ff 10 * 2. Redistributions in binary form must reproduce the above copyright notice,
bogdanm 0:9b334a45a8ff 11 * this list of conditions and the following disclaimer in the documentation
bogdanm 0:9b334a45a8ff 12 * and/or other materials provided with the distribution.
bogdanm 0:9b334a45a8ff 13 * 3. Neither the name of STMicroelectronics nor the names of its contributors
bogdanm 0:9b334a45a8ff 14 * may be used to endorse or promote products derived from this software
bogdanm 0:9b334a45a8ff 15 * without specific prior written permission.
bogdanm 0:9b334a45a8ff 16 *
bogdanm 0:9b334a45a8ff 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
bogdanm 0:9b334a45a8ff 18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
bogdanm 0:9b334a45a8ff 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
bogdanm 0:9b334a45a8ff 20 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
bogdanm 0:9b334a45a8ff 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
bogdanm 0:9b334a45a8ff 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
bogdanm 0:9b334a45a8ff 23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
bogdanm 0:9b334a45a8ff 24 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
bogdanm 0:9b334a45a8ff 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
bogdanm 0:9b334a45a8ff 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
bogdanm 0:9b334a45a8ff 27 */
bogdanm 0:9b334a45a8ff 28 #include <stddef.h>
bogdanm 0:9b334a45a8ff 29 #include "us_ticker_api.h"
bogdanm 0:9b334a45a8ff 30 #include "PeripheralNames.h"
bogdanm 0:9b334a45a8ff 31
bogdanm 0:9b334a45a8ff 32 // Timer selection
bogdanm 0:9b334a45a8ff 33 #define TIM_MST TIM21
bogdanm 0:9b334a45a8ff 34
bogdanm 0:9b334a45a8ff 35 static TIM_HandleTypeDef TimMasterHandle;
bogdanm 0:9b334a45a8ff 36 static int us_ticker_inited = 0;
bogdanm 0:9b334a45a8ff 37
bogdanm 0:9b334a45a8ff 38 volatile uint32_t SlaveCounter = 0;
bogdanm 0:9b334a45a8ff 39 volatile uint32_t oc_int_part = 0;
bogdanm 0:9b334a45a8ff 40 volatile uint16_t oc_rem_part = 0;
bogdanm 0:9b334a45a8ff 41
bogdanm 0:9b334a45a8ff 42 void set_compare(uint16_t count)
bogdanm 0:9b334a45a8ff 43 {
bogdanm 0:9b334a45a8ff 44 TimMasterHandle.Instance = TIM_MST;
bogdanm 0:9b334a45a8ff 45 // Set new output compare value
bogdanm 0:9b334a45a8ff 46 __HAL_TIM_SetCompare(&TimMasterHandle, TIM_CHANNEL_1, count);
bogdanm 0:9b334a45a8ff 47 // Enable IT
bogdanm 0:9b334a45a8ff 48 __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC1);
bogdanm 0:9b334a45a8ff 49 }
bogdanm 0:9b334a45a8ff 50
bogdanm 0:9b334a45a8ff 51 void us_ticker_init(void)
bogdanm 0:9b334a45a8ff 52 {
bogdanm 0:9b334a45a8ff 53 if (us_ticker_inited) return;
bogdanm 0:9b334a45a8ff 54 us_ticker_inited = 1;
bogdanm 0:9b334a45a8ff 55
bogdanm 0:9b334a45a8ff 56 HAL_InitTick(0); // The passed value is not used
bogdanm 0:9b334a45a8ff 57 }
bogdanm 0:9b334a45a8ff 58
bogdanm 0:9b334a45a8ff 59 uint32_t us_ticker_read()
bogdanm 0:9b334a45a8ff 60 {
bogdanm 0:9b334a45a8ff 61 uint32_t counter, counter2;
bogdanm 0:9b334a45a8ff 62 if (!us_ticker_inited) us_ticker_init();
bogdanm 0:9b334a45a8ff 63 // A situation might appear when Master overflows right after Slave is read and before the
bogdanm 0:9b334a45a8ff 64 // new (overflowed) value of Master is read. Which would make the code below consider the
bogdanm 0:9b334a45a8ff 65 // previous (incorrect) value of Slave and the new value of Master, which would return a
bogdanm 0:9b334a45a8ff 66 // value in the past. Avoid this by computing consecutive values of the timer until they
bogdanm 0:9b334a45a8ff 67 // are properly ordered.
bogdanm 0:9b334a45a8ff 68 counter = (uint32_t)(SlaveCounter << 16);
bogdanm 0:9b334a45a8ff 69 counter += TIM_MST->CNT;
bogdanm 0:9b334a45a8ff 70 while (1) {
bogdanm 0:9b334a45a8ff 71 counter2 = (uint32_t)(SlaveCounter << 16);
bogdanm 0:9b334a45a8ff 72 counter2 += TIM_MST->CNT;
bogdanm 0:9b334a45a8ff 73 if (counter2 > counter) {
bogdanm 0:9b334a45a8ff 74 break;
bogdanm 0:9b334a45a8ff 75 }
bogdanm 0:9b334a45a8ff 76 counter = counter2;
bogdanm 0:9b334a45a8ff 77 }
bogdanm 0:9b334a45a8ff 78 return counter2;
bogdanm 0:9b334a45a8ff 79 }
bogdanm 0:9b334a45a8ff 80
bogdanm 0:9b334a45a8ff 81 void us_ticker_set_interrupt(timestamp_t timestamp)
bogdanm 0:9b334a45a8ff 82 {
bogdanm 0:9b334a45a8ff 83 int delta = (int)((uint32_t)timestamp - us_ticker_read());
bogdanm 0:9b334a45a8ff 84 uint16_t cval = TIM_MST->CNT;
bogdanm 0:9b334a45a8ff 85
bogdanm 0:9b334a45a8ff 86 if (delta <= 0) { // This event was in the past
bogdanm 0:9b334a45a8ff 87 us_ticker_irq_handler();
bogdanm 0:9b334a45a8ff 88 } else {
bogdanm 0:9b334a45a8ff 89 oc_int_part = (uint32_t)(delta >> 16);
bogdanm 0:9b334a45a8ff 90 oc_rem_part = (uint16_t)(delta & 0xFFFF);
bogdanm 0:9b334a45a8ff 91 if (oc_rem_part <= (0xFFFF - cval)) {
bogdanm 0:9b334a45a8ff 92 set_compare(cval + oc_rem_part);
bogdanm 0:9b334a45a8ff 93 oc_rem_part = 0;
bogdanm 0:9b334a45a8ff 94 } else {
bogdanm 0:9b334a45a8ff 95 set_compare(0xFFFF);
bogdanm 0:9b334a45a8ff 96 oc_rem_part = oc_rem_part - (0xFFFF - cval);
bogdanm 0:9b334a45a8ff 97 }
bogdanm 0:9b334a45a8ff 98 }
bogdanm 0:9b334a45a8ff 99 }
bogdanm 0:9b334a45a8ff 100
bogdanm 0:9b334a45a8ff 101 void us_ticker_disable_interrupt(void)
bogdanm 0:9b334a45a8ff 102 {
bogdanm 0:9b334a45a8ff 103 TimMasterHandle.Instance = TIM_MST;
bogdanm 0:9b334a45a8ff 104 __HAL_TIM_DISABLE_IT(&TimMasterHandle, TIM_IT_CC1);
bogdanm 0:9b334a45a8ff 105 }
bogdanm 0:9b334a45a8ff 106
bogdanm 0:9b334a45a8ff 107 void us_ticker_clear_interrupt(void)
bogdanm 0:9b334a45a8ff 108 {
bogdanm 0:9b334a45a8ff 109 TimMasterHandle.Instance = TIM_MST;
bogdanm 0:9b334a45a8ff 110 if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC1) == SET) {
bogdanm 0:9b334a45a8ff 111 __HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_CC1);
bogdanm 0:9b334a45a8ff 112 }
bogdanm 0:9b334a45a8ff 113 }