shao ziyang / mbed-src-kl05

mbed library sources

Dependents:   frdm_kl05z_gpio_test

Fork of mbed-src by mbed official

targets/hal/TARGET_NXP/TARGET_LPC43XX/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:
300:55638feb26a4 
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
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 * Ported to NXP LPC43XX by Micromint USA <support@micromint.com>
bogdanm 20:4263a77256ae 17 */
bogdanm 20:4263a77256ae 18 #include <stddef.h>
bogdanm 20:4263a77256ae 19 #include "us_ticker_api.h"
bogdanm 20:4263a77256ae 20 #include "PeripheralNames.h"
bogdanm 20:4263a77256ae 21
bogdanm 20:4263a77256ae 22 #define US_TICKER_TIMER ((LPC_TIMER_T *)LPC_TIMER3_BASE)
bogdanm 20:4263a77256ae 23 #define US_TICKER_TIMER_IRQn TIMER3_IRQn
bogdanm 20:4263a77256ae 24
bogdanm 20:4263a77256ae 25 int us_ticker_inited = 0;
bogdanm 20:4263a77256ae 26
bogdanm 20:4263a77256ae 27 void us_ticker_init(void) {
bogdanm 20:4263a77256ae 28 if (us_ticker_inited) return;
bogdanm 20:4263a77256ae 29 us_ticker_inited = 1;
mbed_official 300:55638feb26a4 30
bogdanm 20:4263a77256ae 31 US_TICKER_TIMER->CTCR = 0x0; // timer mode
bogdanm 20:4263a77256ae 32 uint32_t PCLK = SystemCoreClock;
bogdanm 20:4263a77256ae 33
bogdanm 20:4263a77256ae 34 US_TICKER_TIMER->TCR = 0x2; // reset
mbed_official 300:55638feb26a4 35
bogdanm 20:4263a77256ae 36 uint32_t prescale = PCLK / 1000000; // default to 1MHz (1 us ticks)
bogdanm 20:4263a77256ae 37 US_TICKER_TIMER->PR = prescale - 1;
bogdanm 20:4263a77256ae 38 US_TICKER_TIMER->TCR = 1; // enable = 1, reset = 0
mbed_official 300:55638feb26a4 39
bogdanm 20:4263a77256ae 40 NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler);
bogdanm 20:4263a77256ae 41 NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
bogdanm 20:4263a77256ae 42 }
bogdanm 20:4263a77256ae 43
bogdanm 20:4263a77256ae 44 uint32_t us_ticker_read() {
bogdanm 20:4263a77256ae 45 if (!us_ticker_inited)
bogdanm 20:4263a77256ae 46 us_ticker_init();
mbed_official 300:55638feb26a4 47
bogdanm 20:4263a77256ae 48 return US_TICKER_TIMER->TC;
bogdanm 20:4263a77256ae 49 }
bogdanm 20:4263a77256ae 50
mbed_official 304:89b9c3a9a045 51 void us_ticker_set_interrupt(timestamp_t timestamp) {
bogdanm 20:4263a77256ae 52 // set match value
mbed_official 304:89b9c3a9a045 53 US_TICKER_TIMER->MR[0] = (uint32_t)timestamp;
bogdanm 20:4263a77256ae 54 // enable match interrupt
bogdanm 20:4263a77256ae 55 US_TICKER_TIMER->MCR |= 1;
bogdanm 20:4263a77256ae 56 }
bogdanm 20:4263a77256ae 57
bogdanm 20:4263a77256ae 58 void us_ticker_disable_interrupt(void) {
bogdanm 20:4263a77256ae 59 US_TICKER_TIMER->MCR &= ~1;
bogdanm 20:4263a77256ae 60 }
bogdanm 20:4263a77256ae 61
bogdanm 20:4263a77256ae 62 void us_ticker_clear_interrupt(void) {
bogdanm 20:4263a77256ae 63 US_TICKER_TIMER->IR = 1;
bogdanm 20:4263a77256ae 64 }