Ken Todotani / mbed-src

mbed library sources

Fork of mbed-src by mbed official

targets/hal/TARGET_STM/TARGET_DISCO_F303VC/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:
157:90e3acc479a2 
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 157:90e3acc479a2 1 /* mbed Microcontroller Library
mbed_official 157:90e3acc479a2 2 * Copyright (c) 2014, STMicroelectronics
mbed_official 157:90e3acc479a2 3 * All rights reserved.
mbed_official 157:90e3acc479a2 4 *
mbed_official 157:90e3acc479a2 5 * Redistribution and use in source and binary forms, with or without
mbed_official 157:90e3acc479a2 6 * modification, are permitted provided that the following conditions are met:
mbed_official 157:90e3acc479a2 7 *
mbed_official 157:90e3acc479a2 8 * 1. Redistributions of source code must retain the above copyright notice,
mbed_official 157:90e3acc479a2 9 * this list of conditions and the following disclaimer.
mbed_official 157:90e3acc479a2 10 * 2. Redistributions in binary form must reproduce the above copyright notice,
mbed_official 157:90e3acc479a2 11 * this list of conditions and the following disclaimer in the documentation
mbed_official 157:90e3acc479a2 12 * and/or other materials provided with the distribution.
mbed_official 157:90e3acc479a2 13 * 3. Neither the name of STMicroelectronics nor the names of its contributors
mbed_official 157:90e3acc479a2 14 * may be used to endorse or promote products derived from this software
mbed_official 157:90e3acc479a2 15 * without specific prior written permission.
mbed_official 157:90e3acc479a2 16 *
mbed_official 157:90e3acc479a2 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
mbed_official 157:90e3acc479a2 18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
mbed_official 157:90e3acc479a2 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
mbed_official 157:90e3acc479a2 20 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
mbed_official 157:90e3acc479a2 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
mbed_official 157:90e3acc479a2 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
mbed_official 157:90e3acc479a2 23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 157:90e3acc479a2 24 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
mbed_official 157:90e3acc479a2 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
mbed_official 157:90e3acc479a2 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
mbed_official 157:90e3acc479a2 27 */
mbed_official 157:90e3acc479a2 28 #include <stddef.h>
mbed_official 157:90e3acc479a2 29 #include "us_ticker_api.h"
mbed_official 157:90e3acc479a2 30 #include "PeripheralNames.h"
mbed_official 157:90e3acc479a2 31
mbed_official 157:90e3acc479a2 32 // 32-bit timer selection
mbed_official 157:90e3acc479a2 33 #define TIM_MST TIM2
mbed_official 157:90e3acc479a2 34 #define TIM_MST_IRQ TIM2_IRQn
mbed_official 157:90e3acc479a2 35 #define TIM_MST_RCC RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE)
mbed_official 157:90e3acc479a2 36
mbed_official 157:90e3acc479a2 37 static int us_ticker_inited = 0;
mbed_official 157:90e3acc479a2 38
mbed_official 157:90e3acc479a2 39 void us_ticker_init(void) {
mbed_official 157:90e3acc479a2 40 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
mbed_official 157:90e3acc479a2 41
mbed_official 157:90e3acc479a2 42 if (us_ticker_inited) return;
mbed_official 157:90e3acc479a2 43 us_ticker_inited = 1;
mbed_official 157:90e3acc479a2 44
mbed_official 157:90e3acc479a2 45 // Enable timer clock
mbed_official 157:90e3acc479a2 46 TIM_MST_RCC;
mbed_official 157:90e3acc479a2 47
mbed_official 157:90e3acc479a2 48 // Configure time base
mbed_official 157:90e3acc479a2 49 TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
mbed_official 157:90e3acc479a2 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 157:90e3acc479a2 52 TIM_TimeBaseStructure.TIM_ClockDivision = 0;
mbed_official 157:90e3acc479a2 53 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
mbed_official 157:90e3acc479a2 54 TIM_TimeBaseInit(TIM_MST, &TIM_TimeBaseStructure);
mbed_official 157:90e3acc479a2 55
mbed_official 157:90e3acc479a2 56 NVIC_SetVector(TIM_MST_IRQ, (uint32_t)us_ticker_irq_handler);
mbed_official 157:90e3acc479a2 57 NVIC_EnableIRQ(TIM_MST_IRQ);
mbed_official 157:90e3acc479a2 58
mbed_official 157:90e3acc479a2 59 // Enable timer
mbed_official 157:90e3acc479a2 60 TIM_Cmd(TIM_MST, ENABLE);
mbed_official 157:90e3acc479a2 61 }
mbed_official 157:90e3acc479a2 62
mbed_official 157:90e3acc479a2 63 uint32_t us_ticker_read() {
mbed_official 157:90e3acc479a2 64 if (!us_ticker_inited) us_ticker_init();
mbed_official 157:90e3acc479a2 65 return TIM_MST->CNT;
mbed_official 157:90e3acc479a2 66 }
mbed_official 157:90e3acc479a2 67
mbed_official 304:89b9c3a9a045 68 void us_ticker_set_interrupt(timestamp_t timestamp) {
mbed_official 157:90e3acc479a2 69 // Set new output compare value
mbed_official 304:89b9c3a9a045 70 TIM_SetCompare1(TIM_MST, (uint32_t)timestamp);
mbed_official 157:90e3acc479a2 71 // Enable IT
mbed_official 157:90e3acc479a2 72 TIM_ITConfig(TIM_MST, TIM_IT_CC1, ENABLE);
mbed_official 157:90e3acc479a2 73 }
mbed_official 157:90e3acc479a2 74
mbed_official 157:90e3acc479a2 75 void us_ticker_disable_interrupt(void) {
mbed_official 157:90e3acc479a2 76 TIM_ITConfig(TIM_MST, TIM_IT_CC1, DISABLE);
mbed_official 157:90e3acc479a2 77 }
mbed_official 157:90e3acc479a2 78
mbed_official 157:90e3acc479a2 79 void us_ticker_clear_interrupt(void) {
mbed_official 157:90e3acc479a2 80 TIM_ClearITPendingBit(TIM_MST, TIM_IT_CC1);
mbed_official 157:90e3acc479a2 81 }