mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

Dependents:   Nucleo_Hello_Encoder BLE_iBeaconScan AM1805_DEMO DISCO-F429ZI_ExportTemplate1 ... more

targets/TARGET_NXP/TARGET_LPC176X/us_ticker.c@186:707f6e361f3e, 2018-06-22 (annotated)

Committer:
Anna Bridge
Date:
Fri Jun 22 16:45:37 2018 +0100
Revision:
186:707f6e361f3e
Parent:
174:b96e65c34a4d
Child:
188:bcfe06ba3d64
mbed-dev library. Release version 162

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
Anna Bridge 186:707f6e361f3e 20 const ticker_info_t* us_ticker_get_info()
Anna Bridge 186:707f6e361f3e 21 {
Anna Bridge 186:707f6e361f3e 22 static const ticker_info_t info = {
Anna Bridge 186:707f6e361f3e 23 1000000, // 1 MHz
Anna Bridge 186:707f6e361f3e 24 32 // 32 bit counter
Anna Bridge 186:707f6e361f3e 25 };
Anna Bridge 186:707f6e361f3e 26 return &info;
Anna Bridge 186:707f6e361f3e 27 }
Anna Bridge 186:707f6e361f3e 28
Anna Bridge 186:707f6e361f3e 29 static bool us_ticker_inited = false;
Anna Bridge 186:707f6e361f3e 30
<> 144:ef7eb2e8f9f7 31 #define US_TICKER_TIMER ((LPC_TIM_TypeDef *)LPC_TIM3_BASE)
<> 144:ef7eb2e8f9f7 32 #define US_TICKER_TIMER_IRQn TIMER3_IRQn
<> 144:ef7eb2e8f9f7 33
Anna Bridge 186:707f6e361f3e 34 void us_ticker_init(void) {
Anna Bridge 186:707f6e361f3e 35 if (us_ticker_inited) {
Anna Bridge 186:707f6e361f3e 36 /* calling init again should cancel current interrupt */
Anna Bridge 186:707f6e361f3e 37 us_ticker_disable_interrupt();
Anna Bridge 186:707f6e361f3e 38 return;
Anna Bridge 186:707f6e361f3e 39 }
Anna Bridge 186:707f6e361f3e 40 us_ticker_inited = true;
<> 144:ef7eb2e8f9f7 41
<> 144:ef7eb2e8f9f7 42 LPC_SC->PCONP |= 1 << 23; // Clock TIMER_3
Anna Bridge 186:707f6e361f3e 43
<> 144:ef7eb2e8f9f7 44 US_TICKER_TIMER->CTCR = 0x0; // timer mode
<> 144:ef7eb2e8f9f7 45 uint32_t PCLK = SystemCoreClock / 4;
Anna Bridge 186:707f6e361f3e 46
<> 144:ef7eb2e8f9f7 47 US_TICKER_TIMER->TCR = 0x2; // reset
Anna Bridge 186:707f6e361f3e 48
<> 144:ef7eb2e8f9f7 49 uint32_t prescale = PCLK / 1000000; // default to 1MHz (1 us ticks)
<> 144:ef7eb2e8f9f7 50 US_TICKER_TIMER->PR = prescale - 1;
<> 144:ef7eb2e8f9f7 51 US_TICKER_TIMER->TCR = 1; // enable = 1, reset = 0
Anna Bridge 186:707f6e361f3e 52
<> 144:ef7eb2e8f9f7 53 NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler);
<> 144:ef7eb2e8f9f7 54 NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
<> 144:ef7eb2e8f9f7 55 }
<> 144:ef7eb2e8f9f7 56
<> 144:ef7eb2e8f9f7 57 uint32_t us_ticker_read() {
<> 144:ef7eb2e8f9f7 58 return US_TICKER_TIMER->TC;
<> 144:ef7eb2e8f9f7 59 }
<> 144:ef7eb2e8f9f7 60
<> 144:ef7eb2e8f9f7 61 void us_ticker_set_interrupt(timestamp_t timestamp) {
<> 144:ef7eb2e8f9f7 62 // set match value
<> 144:ef7eb2e8f9f7 63 US_TICKER_TIMER->MR0 = (uint32_t)timestamp;
<> 144:ef7eb2e8f9f7 64 // enable match interrupt
<> 144:ef7eb2e8f9f7 65 US_TICKER_TIMER->MCR |= 1;
<> 144:ef7eb2e8f9f7 66 }
<> 144:ef7eb2e8f9f7 67
AnnaBridge 174:b96e65c34a4d 68 void us_ticker_fire_interrupt(void)
AnnaBridge 174:b96e65c34a4d 69 {
AnnaBridge 174:b96e65c34a4d 70 NVIC_SetPendingIRQ(US_TICKER_TIMER_IRQn);
AnnaBridge 174:b96e65c34a4d 71 }
AnnaBridge 174:b96e65c34a4d 72
<> 144:ef7eb2e8f9f7 73 void us_ticker_disable_interrupt(void) {
<> 144:ef7eb2e8f9f7 74 US_TICKER_TIMER->MCR &= ~1;
<> 144:ef7eb2e8f9f7 75 }
<> 144:ef7eb2e8f9f7 76
<> 144:ef7eb2e8f9f7 77 void us_ticker_clear_interrupt(void) {
<> 144:ef7eb2e8f9f7 78 US_TICKER_TIMER->IR = 1;
<> 144:ef7eb2e8f9f7 79 }