mirror of https://github.com/ARMmbed/mbed-os.git
122 lines
2.9 KiB
C
122 lines
2.9 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2016 - 2018 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#if DEVICE_LPTICKER
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#include "lp_ticker_api.h"
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#include "fsl_lptmr.h"
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#include "cmsis.h"
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const ticker_info_t* lp_ticker_get_info()
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{
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static const ticker_info_t info = {
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32768, // 32kHz
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16 // 16 bit counter
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};
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return &info;
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}
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#define OSC32K_CLK_HZ (32768)
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static bool lp_ticker_inited = false;
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static void lptmr_isr(void)
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{
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LPTMR_ClearStatusFlags(LPTMR0, kLPTMR_TimerCompareFlag);
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lp_ticker_irq_handler();
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}
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/** Initialize the low power ticker
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*
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*/
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void lp_ticker_init(void)
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{
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lptmr_config_t lptmrConfig;
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if (!lp_ticker_inited) {
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/* Setup high resolution clock - LPTMR */
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LPTMR_GetDefaultConfig(&lptmrConfig);
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/* Use 32kHz drive */
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CLOCK_SetXtal32Freq(OSC32K_CLK_HZ);
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lptmrConfig.prescalerClockSource = kLPTMR_PrescalerClock_2;
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lptmrConfig.enableFreeRunning = true;
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LPTMR_Init(LPTMR0, &lptmrConfig);
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LPTMR_DisableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
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NVIC_ClearPendingIRQ(LPTMR0_IRQn);
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NVIC_SetVector(LPTMR0_IRQn, (uint32_t)lptmr_isr);
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EnableIRQ(LPTMR0_IRQn);
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lp_ticker_inited = true;
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} else {
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lp_ticker_disable_interrupt();
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}
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}
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/** Read the current counter
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*
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* @return The current timer's counter value in ticks
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*/
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uint32_t lp_ticker_read(void)
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{
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return LPTMR_GetCurrentTimerCount(LPTMR0);
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}
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/** Set interrupt for specified timestamp
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*
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* @param timestamp The time in ticks to be set
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*/
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void lp_ticker_set_interrupt(timestamp_t timestamp)
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{
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if (timestamp == 0) {
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timestamp = 1;
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}
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LPTMR_SetTimerPeriod(LPTMR0, timestamp);
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LPTMR_ClearStatusFlags(LPTMR0, kLPTMR_TimerCompareFlag);
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LPTMR_EnableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
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LPTMR_StartTimer(LPTMR0);
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}
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void lp_ticker_fire_interrupt(void)
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{
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NVIC_SetPendingIRQ(LPTMR0_IRQn);
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}
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/** Disable low power ticker interrupt
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*
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*/
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void lp_ticker_disable_interrupt(void)
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{
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LPTMR_DisableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
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}
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/** Clear the low power ticker interrupt
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*
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*/
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void lp_ticker_clear_interrupt(void)
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{
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LPTMR_ClearStatusFlags(LPTMR0, kLPTMR_TimerCompareFlag);
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}
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void lp_ticker_free(void)
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{
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LPTMR_DisableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
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NVIC_DisableIRQ(LPTMR0_IRQn);
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}
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#endif /* DEVICE_LPTICKER */
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