EL4121 Embedded System / mbed-os

mbed-os

Dependents:   cobaLCDJoyMotor_Thread odometry_omni_3roda_v3 odometry_omni_3roda_v1 odometry_omni_3roda_v2 ... more

targets/TARGET_NXP/TARGET_LPC176X/us_ticker.c@0:b74591d5ab33, 2017-12-11 (annotated)

Committer:
be_bryan
Date:
Mon Dec 11 17:54:04 2017 +0000
Revision:
0:b74591d5ab33
motor ++

Who changed what in which revision?

UserRevisionLine numberNew contents of line
be_bryan 0:b74591d5ab33 1 /* mbed Microcontroller Library
be_bryan 0:b74591d5ab33 2 * Copyright (c) 2006-2013 ARM Limited
be_bryan 0:b74591d5ab33 3 *
be_bryan 0:b74591d5ab33 4 * Licensed under the Apache License, Version 2.0 (the "License");
be_bryan 0:b74591d5ab33 5 * you may not use this file except in compliance with the License.
be_bryan 0:b74591d5ab33 6 * You may obtain a copy of the License at
be_bryan 0:b74591d5ab33 7 *
be_bryan 0:b74591d5ab33 8 * http://www.apache.org/licenses/LICENSE-2.0
be_bryan 0:b74591d5ab33 9 *
be_bryan 0:b74591d5ab33 10 * Unless required by applicable law or agreed to in writing, software
be_bryan 0:b74591d5ab33 11 * distributed under the License is distributed on an "AS IS" BASIS,
be_bryan 0:b74591d5ab33 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
be_bryan 0:b74591d5ab33 13 * See the License for the specific language governing permissions and
be_bryan 0:b74591d5ab33 14 * limitations under the License.
be_bryan 0:b74591d5ab33 15 */
be_bryan 0:b74591d5ab33 16 #include <stddef.h>
be_bryan 0:b74591d5ab33 17 #include "us_ticker_api.h"
be_bryan 0:b74591d5ab33 18 #include "PeripheralNames.h"
be_bryan 0:b74591d5ab33 19
be_bryan 0:b74591d5ab33 20 #define US_TICKER_TIMER ((LPC_TIM_TypeDef *)LPC_TIM3_BASE)
be_bryan 0:b74591d5ab33 21 #define US_TICKER_TIMER_IRQn TIMER3_IRQn
be_bryan 0:b74591d5ab33 22
be_bryan 0:b74591d5ab33 23 int us_ticker_inited = 0;
be_bryan 0:b74591d5ab33 24
be_bryan 0:b74591d5ab33 25 void us_ticker_init(void) {
be_bryan 0:b74591d5ab33 26 if (us_ticker_inited) return;
be_bryan 0:b74591d5ab33 27 us_ticker_inited = 1;
be_bryan 0:b74591d5ab33 28
be_bryan 0:b74591d5ab33 29 LPC_SC->PCONP |= 1 << 23; // Clock TIMER_3
be_bryan 0:b74591d5ab33 30
be_bryan 0:b74591d5ab33 31 US_TICKER_TIMER->CTCR = 0x0; // timer mode
be_bryan 0:b74591d5ab33 32 uint32_t PCLK = SystemCoreClock / 4;
be_bryan 0:b74591d5ab33 33
be_bryan 0:b74591d5ab33 34 US_TICKER_TIMER->TCR = 0x2; // reset
be_bryan 0:b74591d5ab33 35
be_bryan 0:b74591d5ab33 36 uint32_t prescale = PCLK / 1000000; // default to 1MHz (1 us ticks)
be_bryan 0:b74591d5ab33 37 US_TICKER_TIMER->PR = prescale - 1;
be_bryan 0:b74591d5ab33 38 US_TICKER_TIMER->TCR = 1; // enable = 1, reset = 0
be_bryan 0:b74591d5ab33 39
be_bryan 0:b74591d5ab33 40 NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler);
be_bryan 0:b74591d5ab33 41 NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
be_bryan 0:b74591d5ab33 42 }
be_bryan 0:b74591d5ab33 43
be_bryan 0:b74591d5ab33 44 uint32_t us_ticker_read() {
be_bryan 0:b74591d5ab33 45 if (!us_ticker_inited)
be_bryan 0:b74591d5ab33 46 us_ticker_init();
be_bryan 0:b74591d5ab33 47
be_bryan 0:b74591d5ab33 48 return US_TICKER_TIMER->TC;
be_bryan 0:b74591d5ab33 49 }
be_bryan 0:b74591d5ab33 50
be_bryan 0:b74591d5ab33 51 void us_ticker_set_interrupt(timestamp_t timestamp) {
be_bryan 0:b74591d5ab33 52 // set match value
be_bryan 0:b74591d5ab33 53 US_TICKER_TIMER->MR0 = (uint32_t)timestamp;
be_bryan 0:b74591d5ab33 54 // enable match interrupt
be_bryan 0:b74591d5ab33 55 US_TICKER_TIMER->MCR |= 1;
be_bryan 0:b74591d5ab33 56 }
be_bryan 0:b74591d5ab33 57
be_bryan 0:b74591d5ab33 58 void us_ticker_fire_interrupt(void)
be_bryan 0:b74591d5ab33 59 {
be_bryan 0:b74591d5ab33 60 NVIC_SetPendingIRQ(US_TICKER_TIMER_IRQn);
be_bryan 0:b74591d5ab33 61 }
be_bryan 0:b74591d5ab33 62
be_bryan 0:b74591d5ab33 63 void us_ticker_disable_interrupt(void) {
be_bryan 0:b74591d5ab33 64 US_TICKER_TIMER->MCR &= ~1;
be_bryan 0:b74591d5ab33 65 }
be_bryan 0:b74591d5ab33 66
be_bryan 0:b74591d5ab33 67 void us_ticker_clear_interrupt(void) {
be_bryan 0:b74591d5ab33 68 US_TICKER_TIMER->IR = 1;
be_bryan 0:b74591d5ab33 69 }