shao ziyang / mbed-src-kl05

mbed library sources

Dependents:   frdm_kl05z_gpio_test

Fork of mbed-src by mbed official

targets/hal/TARGET_STM/TARGET_NUCLEO_F334R8/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:
237:f3da66175598 
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 237:f3da66175598 1 /* mbed Microcontroller Library
mbed_official 237:f3da66175598 2 * Copyright (c) 2014, STMicroelectronics
mbed_official 237:f3da66175598 3 * All rights reserved.
mbed_official 237:f3da66175598 4 *
mbed_official 237:f3da66175598 5 * Redistribution and use in source and binary forms, with or without
mbed_official 237:f3da66175598 6 * modification, are permitted provided that the following conditions are met:
mbed_official 237:f3da66175598 7 *
mbed_official 237:f3da66175598 8 * 1. Redistributions of source code must retain the above copyright notice,
mbed_official 237:f3da66175598 9 * this list of conditions and the following disclaimer.
mbed_official 237:f3da66175598 10 * 2. Redistributions in binary form must reproduce the above copyright notice,
mbed_official 237:f3da66175598 11 * this list of conditions and the following disclaimer in the documentation
mbed_official 237:f3da66175598 12 * and/or other materials provided with the distribution.
mbed_official 237:f3da66175598 13 * 3. Neither the name of STMicroelectronics nor the names of its contributors
mbed_official 237:f3da66175598 14 * may be used to endorse or promote products derived from this software
mbed_official 237:f3da66175598 15 * without specific prior written permission.
mbed_official 237:f3da66175598 16 *
mbed_official 237:f3da66175598 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
mbed_official 237:f3da66175598 18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
mbed_official 237:f3da66175598 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
mbed_official 237:f3da66175598 20 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
mbed_official 237:f3da66175598 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
mbed_official 237:f3da66175598 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
mbed_official 237:f3da66175598 23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 237:f3da66175598 24 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
mbed_official 237:f3da66175598 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
mbed_official 237:f3da66175598 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
mbed_official 237:f3da66175598 27 */
mbed_official 237:f3da66175598 28 #include <stddef.h>
mbed_official 237:f3da66175598 29 #include "us_ticker_api.h"
mbed_official 237:f3da66175598 30 #include "PeripheralNames.h"
mbed_official 237:f3da66175598 31
mbed_official 237:f3da66175598 32 // 32-bit timer selection
mbed_official 237:f3da66175598 33 #define TIM_MST TIM2
mbed_official 237:f3da66175598 34 #define TIM_MST_IRQ TIM2_IRQn
mbed_official 237:f3da66175598 35 #define TIM_MST_RCC __TIM2_CLK_ENABLE()
mbed_official 237:f3da66175598 36
mbed_official 237:f3da66175598 37 static TIM_HandleTypeDef TimMasterHandle;
mbed_official 237:f3da66175598 38 static int us_ticker_inited = 0;
mbed_official 237:f3da66175598 39
mbed_official 237:f3da66175598 40 void us_ticker_init(void)
mbed_official 237:f3da66175598 41 {
mbed_official 237:f3da66175598 42 if (us_ticker_inited) return;
mbed_official 237:f3da66175598 43 us_ticker_inited = 1;
mbed_official 237:f3da66175598 44
mbed_official 237:f3da66175598 45 // Enable timer clock
mbed_official 237:f3da66175598 46 TIM_MST_RCC;
mbed_official 237:f3da66175598 47
mbed_official 237:f3da66175598 48 // Update the SystemCoreClock variable
mbed_official 237:f3da66175598 49 SystemCoreClockUpdate();
mbed_official 237:f3da66175598 50
mbed_official 237:f3da66175598 51 // Configure time base
mbed_official 237:f3da66175598 52 TimMasterHandle.Instance = TIM_MST;
mbed_official 237:f3da66175598 53 TimMasterHandle.Init.Period = 0xFFFFFFFF;
mbed_official 304:89b9c3a9a045 54 TimMasterHandle.Init.Prescaler = (uint32_t)(SystemCoreClock / 1000000) - 1; // 1 �s tick
mbed_official 237:f3da66175598 55 TimMasterHandle.Init.ClockDivision = 0;
mbed_official 237:f3da66175598 56 TimMasterHandle.Init.CounterMode = TIM_COUNTERMODE_UP;
mbed_official 237:f3da66175598 57 TimMasterHandle.Init.RepetitionCounter = 0;
mbed_official 237:f3da66175598 58 HAL_TIM_OC_Init(&TimMasterHandle);
mbed_official 237:f3da66175598 59
mbed_official 237:f3da66175598 60 NVIC_SetVector(TIM_MST_IRQ, (uint32_t)us_ticker_irq_handler);
mbed_official 237:f3da66175598 61 NVIC_EnableIRQ(TIM_MST_IRQ);
mbed_official 237:f3da66175598 62
mbed_official 237:f3da66175598 63 // Enable timer
mbed_official 237:f3da66175598 64 HAL_TIM_OC_Start(&TimMasterHandle, TIM_CHANNEL_1);
mbed_official 237:f3da66175598 65 }
mbed_official 237:f3da66175598 66
mbed_official 237:f3da66175598 67 uint32_t us_ticker_read()
mbed_official 237:f3da66175598 68 {
mbed_official 237:f3da66175598 69 if (!us_ticker_inited) us_ticker_init();
mbed_official 237:f3da66175598 70 return TIM_MST->CNT;
mbed_official 237:f3da66175598 71 }
mbed_official 237:f3da66175598 72
mbed_official 304:89b9c3a9a045 73 void us_ticker_set_interrupt(timestamp_t timestamp)
mbed_official 237:f3da66175598 74 {
mbed_official 237:f3da66175598 75 // Set new output compare value
mbed_official 304:89b9c3a9a045 76 __HAL_TIM_SetCompare(&TimMasterHandle, TIM_CHANNEL_1, (uint32_t)timestamp);
mbed_official 237:f3da66175598 77 // Enable IT
mbed_official 237:f3da66175598 78 __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC1);
mbed_official 237:f3da66175598 79 }
mbed_official 237:f3da66175598 80
mbed_official 237:f3da66175598 81 void us_ticker_disable_interrupt(void)
mbed_official 237:f3da66175598 82 {
mbed_official 237:f3da66175598 83 __HAL_TIM_DISABLE_IT(&TimMasterHandle, TIM_IT_CC1);
mbed_official 237:f3da66175598 84 }
mbed_official 237:f3da66175598 85
mbed_official 237:f3da66175598 86 void us_ticker_clear_interrupt(void)
mbed_official 237:f3da66175598 87 {
mbed_official 237:f3da66175598 88 __HAL_TIM_CLEAR_IT(&TimMasterHandle, TIM_IT_CC1);
mbed_official 237:f3da66175598 89 }