li lei / mbed-stm32l0l1-src

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Fork of mbed-stm32l0l1-src-1 by lzbp li

api_source/us_ticker.c@639:b32fded6b0ae, 2016-09-27 (annotated)

Committer:
floatlei
Date:
Tue Sep 27 09:40:53 2016 +0000
Revision:
639:b32fded6b0ae
Parent:
targets/hal/TARGET_STM/TARGET_STM32L0/us_ticker.c@531:47d2b67c511f 
sf

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 376:cb4d9db17537 1 /* mbed Microcontroller Library
mbed_official 531:47d2b67c511f 2 * Copyright (c) 2015, STMicroelectronics
mbed_official 376:cb4d9db17537 3 * All rights reserved.
mbed_official 376:cb4d9db17537 4 *
mbed_official 376:cb4d9db17537 5 * Redistribution and use in source and binary forms, with or without
mbed_official 376:cb4d9db17537 6 * modification, are permitted provided that the following conditions are met:
mbed_official 376:cb4d9db17537 7 *
mbed_official 376:cb4d9db17537 8 * 1. Redistributions of source code must retain the above copyright notice,
mbed_official 376:cb4d9db17537 9 * this list of conditions and the following disclaimer.
mbed_official 376:cb4d9db17537 10 * 2. Redistributions in binary form must reproduce the above copyright notice,
mbed_official 376:cb4d9db17537 11 * this list of conditions and the following disclaimer in the documentation
mbed_official 376:cb4d9db17537 12 * and/or other materials provided with the distribution.
mbed_official 376:cb4d9db17537 13 * 3. Neither the name of STMicroelectronics nor the names of its contributors
mbed_official 376:cb4d9db17537 14 * may be used to endorse or promote products derived from this software
mbed_official 376:cb4d9db17537 15 * without specific prior written permission.
mbed_official 376:cb4d9db17537 16 *
mbed_official 376:cb4d9db17537 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
mbed_official 376:cb4d9db17537 18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
mbed_official 376:cb4d9db17537 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
mbed_official 376:cb4d9db17537 20 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
mbed_official 376:cb4d9db17537 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
mbed_official 376:cb4d9db17537 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
mbed_official 376:cb4d9db17537 23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 376:cb4d9db17537 24 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
mbed_official 376:cb4d9db17537 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
mbed_official 376:cb4d9db17537 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
mbed_official 376:cb4d9db17537 27 */
mbed_official 376:cb4d9db17537 28 #include <stddef.h>
mbed_official 376:cb4d9db17537 29 #include "us_ticker_api.h"
mbed_official 376:cb4d9db17537 30 #include "PeripheralNames.h"
mbed_official 376:cb4d9db17537 31
mbed_official 439:c4382fcbbaed 32 // Timer selection
mbed_official 439:c4382fcbbaed 33 #define TIM_MST TIM21
mbed_official 376:cb4d9db17537 34
mbed_official 376:cb4d9db17537 35 static TIM_HandleTypeDef TimMasterHandle;
mbed_official 439:c4382fcbbaed 36 static int us_ticker_inited = 0;
mbed_official 376:cb4d9db17537 37
mbed_official 439:c4382fcbbaed 38 volatile uint32_t SlaveCounter = 0;
mbed_official 439:c4382fcbbaed 39 volatile uint32_t oc_int_part = 0;
mbed_official 439:c4382fcbbaed 40 volatile uint16_t oc_rem_part = 0;
mbed_official 376:cb4d9db17537 41
mbed_official 439:c4382fcbbaed 42 void set_compare(uint16_t count)
mbed_official 439:c4382fcbbaed 43 {
mbed_official 439:c4382fcbbaed 44 TimMasterHandle.Instance = TIM_MST;
mbed_official 376:cb4d9db17537 45 // Set new output compare value
mbed_official 376:cb4d9db17537 46 __HAL_TIM_SetCompare(&TimMasterHandle, TIM_CHANNEL_1, count);
mbed_official 376:cb4d9db17537 47 // Enable IT
mbed_official 376:cb4d9db17537 48 __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC1);
mbed_official 376:cb4d9db17537 49 }
mbed_official 376:cb4d9db17537 50
mbed_official 439:c4382fcbbaed 51 void us_ticker_init(void)
mbed_official 439:c4382fcbbaed 52 {
mbed_official 376:cb4d9db17537 53 if (us_ticker_inited) return;
mbed_official 376:cb4d9db17537 54 us_ticker_inited = 1;
mbed_official 376:cb4d9db17537 55
mbed_official 439:c4382fcbbaed 56 HAL_InitTick(0); // The passed value is not used
mbed_official 376:cb4d9db17537 57 }
mbed_official 376:cb4d9db17537 58
mbed_official 439:c4382fcbbaed 59 uint32_t us_ticker_read()
mbed_official 439:c4382fcbbaed 60 {
mbed_official 376:cb4d9db17537 61 uint32_t counter, counter2;
mbed_official 376:cb4d9db17537 62 if (!us_ticker_inited) us_ticker_init();
mbed_official 376:cb4d9db17537 63 // A situation might appear when Master overflows right after Slave is read and before the
mbed_official 376:cb4d9db17537 64 // new (overflowed) value of Master is read. Which would make the code below consider the
mbed_official 376:cb4d9db17537 65 // previous (incorrect) value of Slave and the new value of Master, which would return a
mbed_official 376:cb4d9db17537 66 // value in the past. Avoid this by computing consecutive values of the timer until they
mbed_official 376:cb4d9db17537 67 // are properly ordered.
mbed_official 376:cb4d9db17537 68 counter = (uint32_t)(SlaveCounter << 16);
mbed_official 376:cb4d9db17537 69 counter += TIM_MST->CNT;
mbed_official 376:cb4d9db17537 70 while (1) {
mbed_official 376:cb4d9db17537 71 counter2 = (uint32_t)(SlaveCounter << 16);
mbed_official 376:cb4d9db17537 72 counter2 += TIM_MST->CNT;
mbed_official 376:cb4d9db17537 73 if (counter2 > counter) {
mbed_official 376:cb4d9db17537 74 break;
mbed_official 376:cb4d9db17537 75 }
mbed_official 376:cb4d9db17537 76 counter = counter2;
mbed_official 376:cb4d9db17537 77 }
mbed_official 376:cb4d9db17537 78 return counter2;
mbed_official 376:cb4d9db17537 79 }
mbed_official 376:cb4d9db17537 80
mbed_official 439:c4382fcbbaed 81 void us_ticker_set_interrupt(timestamp_t timestamp)
mbed_official 439:c4382fcbbaed 82 {
mbed_official 376:cb4d9db17537 83 int delta = (int)((uint32_t)timestamp - us_ticker_read());
mbed_official 376:cb4d9db17537 84 uint16_t cval = TIM_MST->CNT;
mbed_official 376:cb4d9db17537 85
mbed_official 376:cb4d9db17537 86 if (delta <= 0) { // This event was in the past
mbed_official 376:cb4d9db17537 87 us_ticker_irq_handler();
mbed_official 376:cb4d9db17537 88 } else {
mbed_official 376:cb4d9db17537 89 oc_int_part = (uint32_t)(delta >> 16);
mbed_official 376:cb4d9db17537 90 oc_rem_part = (uint16_t)(delta & 0xFFFF);
mbed_official 376:cb4d9db17537 91 if (oc_rem_part <= (0xFFFF - cval)) {
mbed_official 376:cb4d9db17537 92 set_compare(cval + oc_rem_part);
mbed_official 376:cb4d9db17537 93 oc_rem_part = 0;
mbed_official 376:cb4d9db17537 94 } else {
mbed_official 376:cb4d9db17537 95 set_compare(0xFFFF);
mbed_official 376:cb4d9db17537 96 oc_rem_part = oc_rem_part - (0xFFFF - cval);
mbed_official 376:cb4d9db17537 97 }
mbed_official 376:cb4d9db17537 98 }
mbed_official 376:cb4d9db17537 99 }
mbed_official 376:cb4d9db17537 100
mbed_official 439:c4382fcbbaed 101 void us_ticker_disable_interrupt(void)
mbed_official 439:c4382fcbbaed 102 {
mbed_official 439:c4382fcbbaed 103 TimMasterHandle.Instance = TIM_MST;
mbed_official 376:cb4d9db17537 104 __HAL_TIM_DISABLE_IT(&TimMasterHandle, TIM_IT_CC1);
mbed_official 376:cb4d9db17537 105 }
mbed_official 376:cb4d9db17537 106
mbed_official 439:c4382fcbbaed 107 void us_ticker_clear_interrupt(void)
mbed_official 439:c4382fcbbaed 108 {
mbed_official 439:c4382fcbbaed 109 TimMasterHandle.Instance = TIM_MST;
mbed_official 439:c4382fcbbaed 110 if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC1) == SET) {
mbed_official 439:c4382fcbbaed 111 __HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_CC1);
mbed_official 439:c4382fcbbaed 112 }
mbed_official 376:cb4d9db17537 113 }