Umar Naeem / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed-dev by Umar Naeem

targets/TARGET_NXP/TARGET_LPC176X/us_ticker.c@165:2dd56e6daeec, 2017-05-23 (annotated)

Committer:
ranaumarnaeem
Date:
Tue May 23 12:54:50 2017 +0000
Revision:
165:2dd56e6daeec
Parent:
149:156823d33999 
jhjg

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /* mbed Microcontroller Library
<> 144:ef7eb2e8f9f7 2 * Copyright (c) 2006-2013 ARM Limited
<> 144:ef7eb2e8f9f7 3 *
<> 144:ef7eb2e8f9f7 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 144:ef7eb2e8f9f7 5 * you may not use this file except in compliance with the License.
<> 144:ef7eb2e8f9f7 6 * You may obtain a copy of the License at
<> 144:ef7eb2e8f9f7 7 *
<> 144:ef7eb2e8f9f7 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 144:ef7eb2e8f9f7 9 *
<> 144:ef7eb2e8f9f7 10 * Unless required by applicable law or agreed to in writing, software
<> 144:ef7eb2e8f9f7 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 144:ef7eb2e8f9f7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 144:ef7eb2e8f9f7 13 * See the License for the specific language governing permissions and
<> 144:ef7eb2e8f9f7 14 * limitations under the License.
<> 144:ef7eb2e8f9f7 15 */
<> 144:ef7eb2e8f9f7 16 #include <stddef.h>
<> 144:ef7eb2e8f9f7 17 #include "us_ticker_api.h"
<> 144:ef7eb2e8f9f7 18 #include "PeripheralNames.h"
<> 144:ef7eb2e8f9f7 19
<> 144:ef7eb2e8f9f7 20 #define US_TICKER_TIMER ((LPC_TIM_TypeDef *)LPC_TIM3_BASE)
<> 144:ef7eb2e8f9f7 21 #define US_TICKER_TIMER_IRQn TIMER3_IRQn
<> 144:ef7eb2e8f9f7 22
<> 144:ef7eb2e8f9f7 23 int us_ticker_inited = 0;
<> 144:ef7eb2e8f9f7 24
<> 144:ef7eb2e8f9f7 25 void us_ticker_init(void) {
<> 144:ef7eb2e8f9f7 26 if (us_ticker_inited) return;
<> 144:ef7eb2e8f9f7 27 us_ticker_inited = 1;
<> 144:ef7eb2e8f9f7 28
<> 144:ef7eb2e8f9f7 29 LPC_SC->PCONP |= 1 << 23; // Clock TIMER_3
<> 144:ef7eb2e8f9f7 30
<> 144:ef7eb2e8f9f7 31 US_TICKER_TIMER->CTCR = 0x0; // timer mode
<> 144:ef7eb2e8f9f7 32 uint32_t PCLK = SystemCoreClock / 4;
<> 144:ef7eb2e8f9f7 33
<> 144:ef7eb2e8f9f7 34 US_TICKER_TIMER->TCR = 0x2; // reset
<> 144:ef7eb2e8f9f7 35
<> 144:ef7eb2e8f9f7 36 uint32_t prescale = PCLK / 1000000; // default to 1MHz (1 us ticks)
<> 144:ef7eb2e8f9f7 37 US_TICKER_TIMER->PR = prescale - 1;
<> 144:ef7eb2e8f9f7 38 US_TICKER_TIMER->TCR = 1; // enable = 1, reset = 0
<> 144:ef7eb2e8f9f7 39
<> 144:ef7eb2e8f9f7 40 NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler);
<> 144:ef7eb2e8f9f7 41 NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
<> 144:ef7eb2e8f9f7 42 }
<> 144:ef7eb2e8f9f7 43
<> 144:ef7eb2e8f9f7 44 uint32_t us_ticker_read() {
<> 144:ef7eb2e8f9f7 45 if (!us_ticker_inited)
<> 144:ef7eb2e8f9f7 46 us_ticker_init();
<> 144:ef7eb2e8f9f7 47
<> 144:ef7eb2e8f9f7 48 return US_TICKER_TIMER->TC;
<> 144:ef7eb2e8f9f7 49 }
<> 144:ef7eb2e8f9f7 50
<> 144:ef7eb2e8f9f7 51 void us_ticker_set_interrupt(timestamp_t timestamp) {
<> 144:ef7eb2e8f9f7 52 // set match value
<> 144:ef7eb2e8f9f7 53 US_TICKER_TIMER->MR0 = (uint32_t)timestamp;
<> 144:ef7eb2e8f9f7 54 // enable match interrupt
<> 144:ef7eb2e8f9f7 55 US_TICKER_TIMER->MCR |= 1;
<> 144:ef7eb2e8f9f7 56 }
<> 144:ef7eb2e8f9f7 57
<> 144:ef7eb2e8f9f7 58 void us_ticker_disable_interrupt(void) {
<> 144:ef7eb2e8f9f7 59 US_TICKER_TIMER->MCR &= ~1;
<> 144:ef7eb2e8f9f7 60 }
<> 144:ef7eb2e8f9f7 61
<> 144:ef7eb2e8f9f7 62 void us_ticker_clear_interrupt(void) {
<> 144:ef7eb2e8f9f7 63 US_TICKER_TIMER->IR = 1;
<> 144:ef7eb2e8f9f7 64 }