mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
targets/hal/TARGET_STM/TARGET_STM32F4XX/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:
- 20:4263a77256ae
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?
User | Revision | Line number | New contents of line |
---|---|---|---|
bogdanm | 20:4263a77256ae | 1 | /* mbed Microcontroller Library |
bogdanm | 20:4263a77256ae | 2 | * Copyright (c) 2006-2013 ARM Limited |
bogdanm | 20:4263a77256ae | 3 | * |
bogdanm | 20:4263a77256ae | 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
bogdanm | 20:4263a77256ae | 5 | * you may not use this file except in compliance with the License. |
bogdanm | 20:4263a77256ae | 6 | * You may obtain a copy of the License at |
bogdanm | 20:4263a77256ae | 7 | * |
bogdanm | 20:4263a77256ae | 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
bogdanm | 20:4263a77256ae | 9 | * |
bogdanm | 20:4263a77256ae | 10 | * Unless required by applicable law or agreed to in writing, software |
bogdanm | 20:4263a77256ae | 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
bogdanm | 20:4263a77256ae | 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
bogdanm | 20:4263a77256ae | 13 | * See the License for the specific language governing permissions and |
bogdanm | 20:4263a77256ae | 14 | * limitations under the License. |
bogdanm | 20:4263a77256ae | 15 | */ |
bogdanm | 20:4263a77256ae | 16 | #include <stddef.h> |
bogdanm | 20:4263a77256ae | 17 | #include "us_ticker_api.h" |
bogdanm | 20:4263a77256ae | 18 | #include "PeripheralNames.h" |
bogdanm | 20:4263a77256ae | 19 | |
bogdanm | 20:4263a77256ae | 20 | #define US_TICKER_TIMER TIM2 |
bogdanm | 20:4263a77256ae | 21 | #define US_TICKER_TIMER_IRQn TIM2_IRQn |
bogdanm | 20:4263a77256ae | 22 | |
bogdanm | 20:4263a77256ae | 23 | int us_ticker_inited = 0; |
bogdanm | 20:4263a77256ae | 24 | |
bogdanm | 20:4263a77256ae | 25 | void us_ticker_init(void) { |
bogdanm | 20:4263a77256ae | 26 | if (us_ticker_inited) return; |
bogdanm | 20:4263a77256ae | 27 | us_ticker_inited = 1; |
bogdanm | 20:4263a77256ae | 28 | |
bogdanm | 20:4263a77256ae | 29 | RCC->APB1ENR |= RCC_APB1ENR_TIM2EN; |
bogdanm | 20:4263a77256ae | 30 | |
bogdanm | 20:4263a77256ae | 31 | uint32_t PCLK = SystemCoreClock / 4; |
bogdanm | 20:4263a77256ae | 32 | |
bogdanm | 20:4263a77256ae | 33 | uint32_t prescale = PCLK / 1000000; // default to 1MHz (1 us ticks) |
bogdanm | 20:4263a77256ae | 34 | US_TICKER_TIMER->PSC = prescale - 1; |
bogdanm | 20:4263a77256ae | 35 | US_TICKER_TIMER->CR1 |= TIM_CR1_CEN; |
bogdanm | 20:4263a77256ae | 36 | // Trigger an update - this needs to happen after the counter is enabled. |
bogdanm | 20:4263a77256ae | 37 | US_TICKER_TIMER->EGR |= TIM_EGR_UG; |
bogdanm | 20:4263a77256ae | 38 | |
bogdanm | 20:4263a77256ae | 39 | NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler); |
bogdanm | 20:4263a77256ae | 40 | NVIC_EnableIRQ(US_TICKER_TIMER_IRQn); |
bogdanm | 20:4263a77256ae | 41 | } |
bogdanm | 20:4263a77256ae | 42 | |
bogdanm | 20:4263a77256ae | 43 | uint32_t us_ticker_read() { |
bogdanm | 20:4263a77256ae | 44 | if (!us_ticker_inited) |
bogdanm | 20:4263a77256ae | 45 | us_ticker_init(); |
bogdanm | 20:4263a77256ae | 46 | |
bogdanm | 20:4263a77256ae | 47 | return US_TICKER_TIMER->CNT; |
bogdanm | 20:4263a77256ae | 48 | } |
bogdanm | 20:4263a77256ae | 49 | |
mbed_official | 304:89b9c3a9a045 | 50 | void us_ticker_set_interrupt(timestamp_t timestamp) { |
bogdanm | 20:4263a77256ae | 51 | // set match value |
mbed_official | 304:89b9c3a9a045 | 52 | US_TICKER_TIMER->CCR1 = (uint32_t)timestamp; |
bogdanm | 20:4263a77256ae | 53 | // enable compare interrupt |
bogdanm | 20:4263a77256ae | 54 | US_TICKER_TIMER->DIER |= TIM_DIER_CC1IE; |
bogdanm | 20:4263a77256ae | 55 | } |
bogdanm | 20:4263a77256ae | 56 | |
bogdanm | 20:4263a77256ae | 57 | void us_ticker_disable_interrupt(void) { |
bogdanm | 20:4263a77256ae | 58 | US_TICKER_TIMER->DIER &= ~TIM_DIER_CC1IE; |
bogdanm | 20:4263a77256ae | 59 | } |
bogdanm | 20:4263a77256ae | 60 | |
bogdanm | 20:4263a77256ae | 61 | void us_ticker_clear_interrupt(void) { |
bogdanm | 20:4263a77256ae | 62 | US_TICKER_TIMER->SR &= ~TIM_SR_CC1IF; |
bogdanm | 20:4263a77256ae | 63 | } |