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targets/hal/TARGET_NXP/TARGET_LPC23XX/us_ticker.c@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
Initial commit on mbed-dev



Replaces mbed-src (now inactive)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 0:9b334a45a8ff 1 /* mbed Microcontroller Library
bogdanm 0:9b334a45a8ff 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 0:9b334a45a8ff 3 *
bogdanm 0:9b334a45a8ff 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 0:9b334a45a8ff 5 * you may not use this file except in compliance with the License.
bogdanm 0:9b334a45a8ff 6 * You may obtain a copy of the License at
bogdanm 0:9b334a45a8ff 7 *
bogdanm 0:9b334a45a8ff 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 0:9b334a45a8ff 9 *
bogdanm 0:9b334a45a8ff 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 0:9b334a45a8ff 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 0:9b334a45a8ff 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 0:9b334a45a8ff 13 * See the License for the specific language governing permissions and
bogdanm 0:9b334a45a8ff 14 * limitations under the License.
bogdanm 0:9b334a45a8ff 15 */
bogdanm 0:9b334a45a8ff 16 #include <stddef.h>
bogdanm 0:9b334a45a8ff 17 #include "us_ticker_api.h"
bogdanm 0:9b334a45a8ff 18 #include "PeripheralNames.h"
bogdanm 0:9b334a45a8ff 19
bogdanm 0:9b334a45a8ff 20 #define US_TICKER_TIMER ((LPC_TIM_TypeDef *)LPC_TIM3_BASE)
bogdanm 0:9b334a45a8ff 21 #define US_TICKER_TIMER_IRQn TIMER3_IRQn
bogdanm 0:9b334a45a8ff 22
bogdanm 0:9b334a45a8ff 23 int us_ticker_inited = 0;
bogdanm 0:9b334a45a8ff 24
bogdanm 0:9b334a45a8ff 25 void us_ticker_init(void) {
bogdanm 0:9b334a45a8ff 26 if (us_ticker_inited) return;
bogdanm 0:9b334a45a8ff 27 us_ticker_inited = 1;
bogdanm 0:9b334a45a8ff 28
bogdanm 0:9b334a45a8ff 29 LPC_SC->PCONP |= 1 << 23; // Clock TIMER_3
bogdanm 0:9b334a45a8ff 30
bogdanm 0:9b334a45a8ff 31 US_TICKER_TIMER->CTCR = 0x0; // timer mode
bogdanm 0:9b334a45a8ff 32 uint32_t PCLK = SystemCoreClock / 4;
bogdanm 0:9b334a45a8ff 33
bogdanm 0:9b334a45a8ff 34 US_TICKER_TIMER->TCR = 0x2; // reset
bogdanm 0:9b334a45a8ff 35
bogdanm 0:9b334a45a8ff 36 uint32_t prescale = PCLK / 1000000; // default to 1MHz (1 us ticks)
bogdanm 0:9b334a45a8ff 37 US_TICKER_TIMER->PR = prescale - 1;
bogdanm 0:9b334a45a8ff 38 US_TICKER_TIMER->TCR = 1; // enable = 1, reset = 0
bogdanm 0:9b334a45a8ff 39
bogdanm 0:9b334a45a8ff 40 NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler);
bogdanm 0:9b334a45a8ff 41 NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
bogdanm 0:9b334a45a8ff 42 }
bogdanm 0:9b334a45a8ff 43
bogdanm 0:9b334a45a8ff 44 uint32_t us_ticker_read() {
bogdanm 0:9b334a45a8ff 45 if (!us_ticker_inited)
bogdanm 0:9b334a45a8ff 46 us_ticker_init();
bogdanm 0:9b334a45a8ff 47
bogdanm 0:9b334a45a8ff 48 return US_TICKER_TIMER->TC;
bogdanm 0:9b334a45a8ff 49 }
bogdanm 0:9b334a45a8ff 50
bogdanm 0:9b334a45a8ff 51 void us_ticker_set_interrupt(timestamp_t timestamp) {
bogdanm 0:9b334a45a8ff 52 // set match value
bogdanm 0:9b334a45a8ff 53 US_TICKER_TIMER->MR0 = (uint32_t)timestamp;
bogdanm 0:9b334a45a8ff 54 // enable match interrupt
bogdanm 0:9b334a45a8ff 55 US_TICKER_TIMER->MCR |= 1;
bogdanm 0:9b334a45a8ff 56 }
bogdanm 0:9b334a45a8ff 57
bogdanm 0:9b334a45a8ff 58 void us_ticker_disable_interrupt(void) {
bogdanm 0:9b334a45a8ff 59 US_TICKER_TIMER->MCR &= ~1;
bogdanm 0:9b334a45a8ff 60 }
bogdanm 0:9b334a45a8ff 61
bogdanm 0:9b334a45a8ff 62 void us_ticker_clear_interrupt(void) {
bogdanm 0:9b334a45a8ff 63 US_TICKER_TIMER->IR = 1;
bogdanm 0:9b334a45a8ff 64 }