Thomas Byrne / mbed-src-stm32f030k6

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targets/hal/TARGET_STM/TARGET_STM32F3XX/us_ticker.c@304:89b9c3a9a045, 2014-08-29 (annotated)

Committer:
mbed_official
Date:
Fri Aug 29 17:15:07 2014 +0100
Revision:
304:89b9c3a9a045
Parent:
155:8435094ec241 
Synchronized with git revision 734f365d7da26ef199751f4b0d91611479b495ea



Full URL: https://github.com/mbedmicro/mbed/commit/734f365d7da26ef199751f4b0d91611479b495ea/



1. timestamp_t as an abstraction for time values managed by

   Ticker. Using uint64_t for timestamp_t allows a wraparound-free

   Ticker. This change forces us to update the definitions of usTicker

   for all platforms; but the changes beyond nRF51822 aren't major.



2. reduce power consumption on the nRF51822 by removing the need for

   the high-frequency processor timer; and reimplementing it using the

   RTC.



I've also replaced high-frequency clock with low-frequency external

clock during system startup of the nRF51822. This brings a major win

in power consumption.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 155:8435094ec241 1 /* mbed Microcontroller Library
mbed_official 155:8435094ec241 2 * Copyright (c) 2014, STMicroelectronics
mbed_official 155:8435094ec241 3 * All rights reserved.
mbed_official 155:8435094ec241 4 *
mbed_official 155:8435094ec241 5 * Redistribution and use in source and binary forms, with or without
mbed_official 155:8435094ec241 6 * modification, are permitted provided that the following conditions are met:
mbed_official 155:8435094ec241 7 *
mbed_official 155:8435094ec241 8 * 1. Redistributions of source code must retain the above copyright notice,
mbed_official 155:8435094ec241 9 * this list of conditions and the following disclaimer.
mbed_official 155:8435094ec241 10 * 2. Redistributions in binary form must reproduce the above copyright notice,
mbed_official 155:8435094ec241 11 * this list of conditions and the following disclaimer in the documentation
mbed_official 155:8435094ec241 12 * and/or other materials provided with the distribution.
mbed_official 155:8435094ec241 13 * 3. Neither the name of STMicroelectronics nor the names of its contributors
mbed_official 155:8435094ec241 14 * may be used to endorse or promote products derived from this software
mbed_official 155:8435094ec241 15 * without specific prior written permission.
mbed_official 155:8435094ec241 16 *
mbed_official 155:8435094ec241 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
mbed_official 155:8435094ec241 18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
mbed_official 155:8435094ec241 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
mbed_official 155:8435094ec241 20 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
mbed_official 155:8435094ec241 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
mbed_official 155:8435094ec241 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
mbed_official 155:8435094ec241 23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 155:8435094ec241 24 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
mbed_official 155:8435094ec241 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
mbed_official 155:8435094ec241 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
mbed_official 155:8435094ec241 27 */
mbed_official 155:8435094ec241 28 #include <stddef.h>
mbed_official 155:8435094ec241 29 #include "us_ticker_api.h"
mbed_official 155:8435094ec241 30 #include "PeripheralNames.h"
mbed_official 155:8435094ec241 31
mbed_official 155:8435094ec241 32 // 32-bit timer selection
mbed_official 155:8435094ec241 33 #define TIM_MST TIM2
mbed_official 155:8435094ec241 34 #define TIM_MST_IRQ TIM2_IRQn
mbed_official 155:8435094ec241 35 #define TIM_MST_RCC RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE)
mbed_official 155:8435094ec241 36
mbed_official 155:8435094ec241 37 static int us_ticker_inited = 0;
mbed_official 155:8435094ec241 38
mbed_official 155:8435094ec241 39 void us_ticker_init(void) {
mbed_official 155:8435094ec241 40 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
mbed_official 155:8435094ec241 41
mbed_official 155:8435094ec241 42 if (us_ticker_inited) return;
mbed_official 155:8435094ec241 43 us_ticker_inited = 1;
mbed_official 155:8435094ec241 44
mbed_official 155:8435094ec241 45 // Enable timer clock
mbed_official 155:8435094ec241 46 TIM_MST_RCC;
mbed_official 155:8435094ec241 47
mbed_official 155:8435094ec241 48 // Configure time base
mbed_official 155:8435094ec241 49 TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
mbed_official 155:8435094ec241 50 TIM_TimeBaseStructure.TIM_Period = 0xFFFFFFFF;
mbed_official 304:89b9c3a9a045 51 TIM_TimeBaseStructure.TIM_Prescaler = (uint16_t)(SystemCoreClock / 1000000) - 1; // 1 �s tick
mbed_official 155:8435094ec241 52 TIM_TimeBaseStructure.TIM_ClockDivision = 0;
mbed_official 155:8435094ec241 53 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
mbed_official 155:8435094ec241 54 TIM_TimeBaseInit(TIM_MST, &TIM_TimeBaseStructure);
mbed_official 155:8435094ec241 55
mbed_official 155:8435094ec241 56 NVIC_SetVector(TIM_MST_IRQ, (uint32_t)us_ticker_irq_handler);
mbed_official 155:8435094ec241 57 NVIC_EnableIRQ(TIM_MST_IRQ);
mbed_official 155:8435094ec241 58
mbed_official 155:8435094ec241 59 // Enable timer
mbed_official 155:8435094ec241 60 TIM_Cmd(TIM_MST, ENABLE);
mbed_official 155:8435094ec241 61 }
mbed_official 155:8435094ec241 62
mbed_official 155:8435094ec241 63 uint32_t us_ticker_read() {
mbed_official 155:8435094ec241 64 if (!us_ticker_inited) us_ticker_init();
mbed_official 155:8435094ec241 65 return TIM_MST->CNT;
mbed_official 155:8435094ec241 66 }
mbed_official 155:8435094ec241 67
mbed_official 304:89b9c3a9a045 68 void us_ticker_set_interrupt(timestamp_t timestamp) {
mbed_official 155:8435094ec241 69 // Set new output compare value
mbed_official 304:89b9c3a9a045 70 TIM_SetCompare1(TIM_MST, (uint32_t)timestamp);
mbed_official 155:8435094ec241 71 // Enable IT
mbed_official 155:8435094ec241 72 TIM_ITConfig(TIM_MST, TIM_IT_CC1, ENABLE);
mbed_official 155:8435094ec241 73 }
mbed_official 155:8435094ec241 74
mbed_official 155:8435094ec241 75 void us_ticker_disable_interrupt(void) {
mbed_official 155:8435094ec241 76 TIM_ITConfig(TIM_MST, TIM_IT_CC1, DISABLE);
mbed_official 155:8435094ec241 77 }
mbed_official 155:8435094ec241 78
mbed_official 155:8435094ec241 79 void us_ticker_clear_interrupt(void) {
mbed_official 155:8435094ec241 80 TIM_ClearITPendingBit(TIM_MST, TIM_IT_CC1);
mbed_official 155:8435094ec241 81 }