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mbed SDK library sources

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Development branch of the mbed library sources. This library is kept in synch with the latest changes from the mbed SDK and it is not guaranteed to work.

If you are looking for a stable and tested release, please import one of the official mbed library releases:

Import librarymbed

The official Mbed 2 C/C++ SDK provides the software platform and libraries to build your applications.

Last commit 20 Feb 2019 by mbed official

targets/hal/TARGET_NXP/TARGET_LPC81X/us_ticker.c@46:bebbbd80dd87, 2013-11-11 (annotated)

Committer:
mbed_official
Date:
Mon Nov 11 13:30:09 2013 +0000
Revision:
46:bebbbd80dd87
Synchronized with git revision b2733e9b9af906952b295cd6abcf916bf79780ab

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 46:bebbbd80dd87 1 /* mbed Microcontroller Library
mbed_official 46:bebbbd80dd87 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 46:bebbbd80dd87 3 *
mbed_official 46:bebbbd80dd87 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 46:bebbbd80dd87 5 * you may not use this file except in compliance with the License.
mbed_official 46:bebbbd80dd87 6 * You may obtain a copy of the License at
mbed_official 46:bebbbd80dd87 7 *
mbed_official 46:bebbbd80dd87 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 46:bebbbd80dd87 9 *
mbed_official 46:bebbbd80dd87 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 46:bebbbd80dd87 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 46:bebbbd80dd87 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 46:bebbbd80dd87 13 * See the License for the specific language governing permissions and
mbed_official 46:bebbbd80dd87 14 * limitations under the License.
mbed_official 46:bebbbd80dd87 15 */
mbed_official 46:bebbbd80dd87 16 #include <stddef.h>
mbed_official 46:bebbbd80dd87 17 #include "us_ticker_api.h"
mbed_official 46:bebbbd80dd87 18 #include "PeripheralNames.h"
mbed_official 46:bebbbd80dd87 19
mbed_official 46:bebbbd80dd87 20 #define US_TICKER_TIMER_IRQn SCT_IRQn
mbed_official 46:bebbbd80dd87 21
mbed_official 46:bebbbd80dd87 22 int us_ticker_inited = 0;
mbed_official 46:bebbbd80dd87 23
mbed_official 46:bebbbd80dd87 24 void us_ticker_init(void) {
mbed_official 46:bebbbd80dd87 25 if (us_ticker_inited) return;
mbed_official 46:bebbbd80dd87 26 us_ticker_inited = 1;
mbed_official 46:bebbbd80dd87 27
mbed_official 46:bebbbd80dd87 28 // Enable the SCT clock
mbed_official 46:bebbbd80dd87 29 LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 8);
mbed_official 46:bebbbd80dd87 30
mbed_official 46:bebbbd80dd87 31 // Clear peripheral reset the SCT:
mbed_official 46:bebbbd80dd87 32 LPC_SYSCON->PRESETCTRL |= (1 << 8);
mbed_official 46:bebbbd80dd87 33
mbed_official 46:bebbbd80dd87 34 // Unified counter (32 bits)
mbed_official 46:bebbbd80dd87 35 LPC_SCT->CONFIG |= 1;
mbed_official 46:bebbbd80dd87 36
mbed_official 46:bebbbd80dd87 37 // halt and clear the counter
mbed_official 46:bebbbd80dd87 38 LPC_SCT->CTRL_L |= (1 << 2) | (1 << 3);
mbed_official 46:bebbbd80dd87 39
mbed_official 46:bebbbd80dd87 40 // System Clock (12)MHz -> us_ticker (1)MHz
mbed_official 46:bebbbd80dd87 41 LPC_SCT->CTRL_L |= ((SystemCoreClock/1000000 - 1) << 5);
mbed_official 46:bebbbd80dd87 42
mbed_official 46:bebbbd80dd87 43 // unhalt the counter:
mbed_official 46:bebbbd80dd87 44 // - clearing bit 2 of the CTRL register
mbed_official 46:bebbbd80dd87 45 LPC_SCT->CTRL_L &= ~(1 << 2);
mbed_official 46:bebbbd80dd87 46
mbed_official 46:bebbbd80dd87 47 NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler);
mbed_official 46:bebbbd80dd87 48 NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
mbed_official 46:bebbbd80dd87 49 }
mbed_official 46:bebbbd80dd87 50
mbed_official 46:bebbbd80dd87 51 uint32_t us_ticker_read() {
mbed_official 46:bebbbd80dd87 52 if (!us_ticker_inited)
mbed_official 46:bebbbd80dd87 53 us_ticker_init();
mbed_official 46:bebbbd80dd87 54
mbed_official 46:bebbbd80dd87 55 return LPC_SCT->COUNT_U;
mbed_official 46:bebbbd80dd87 56 }
mbed_official 46:bebbbd80dd87 57
mbed_official 46:bebbbd80dd87 58 void us_ticker_set_interrupt(unsigned int timestamp) {
mbed_official 46:bebbbd80dd87 59 // halt the counter:
mbed_official 46:bebbbd80dd87 60 // - setting bit 2 of the CTRL register
mbed_official 46:bebbbd80dd87 61 LPC_SCT->CTRL_L |= (1 << 2);
mbed_official 46:bebbbd80dd87 62
mbed_official 46:bebbbd80dd87 63 // set timestamp in compare register
mbed_official 46:bebbbd80dd87 64 LPC_SCT->MATCH[0].U = timestamp;
mbed_official 46:bebbbd80dd87 65
mbed_official 46:bebbbd80dd87 66 // unhalt the counter:
mbed_official 46:bebbbd80dd87 67 // - clearing bit 2 of the CTRL register
mbed_official 46:bebbbd80dd87 68 LPC_SCT->CTRL_L &= ~(1 << 2);
mbed_official 46:bebbbd80dd87 69
mbed_official 46:bebbbd80dd87 70 // if events are not enabled, enable them
mbed_official 46:bebbbd80dd87 71 if (!(LPC_SCT->EVEN & 0x01)) {
mbed_official 46:bebbbd80dd87 72
mbed_official 46:bebbbd80dd87 73 // comb mode = match only
mbed_official 46:bebbbd80dd87 74 LPC_SCT->EVENT[0].CTRL = (1 << 12);
mbed_official 46:bebbbd80dd87 75
mbed_official 46:bebbbd80dd87 76 // ref manual:
mbed_official 46:bebbbd80dd87 77 // In simple applications that do not
mbed_official 46:bebbbd80dd87 78 // use states, write 0x01 to this
mbed_official 46:bebbbd80dd87 79 // register to enable an event
mbed_official 46:bebbbd80dd87 80 LPC_SCT->EVENT[0].STATE |= 0x1;
mbed_official 46:bebbbd80dd87 81
mbed_official 46:bebbbd80dd87 82 // enable events
mbed_official 46:bebbbd80dd87 83 LPC_SCT->EVEN |= 0x1;
mbed_official 46:bebbbd80dd87 84 }
mbed_official 46:bebbbd80dd87 85 }
mbed_official 46:bebbbd80dd87 86
mbed_official 46:bebbbd80dd87 87 void us_ticker_disable_interrupt(void) {
mbed_official 46:bebbbd80dd87 88 LPC_SCT->EVEN &= ~1;
mbed_official 46:bebbbd80dd87 89 }
mbed_official 46:bebbbd80dd87 90
mbed_official 46:bebbbd80dd87 91 void us_ticker_clear_interrupt(void) {
mbed_official 46:bebbbd80dd87 92 LPC_SCT->EVFLAG = 1;
mbed_official 46:bebbbd80dd87 93 }