mirror of https://github.com/ARMmbed/mbed-os.git
109 lines
3.2 KiB
C
109 lines
3.2 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2017-2018 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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/**
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* Supports the Low Power Ticker for mbed by implementing \ref lp_ticker_api.h,
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* using both timers in a CMSDK Dual Timer \ref dualtimer_cmsdk_dev_t.
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*/
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#include "dualtimer_cmsdk_drv.h"
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#include "lp_ticker_api.h"
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#include "platform_devices.h"
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static uint32_t last_read = 0;
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/* Initializes both timers in the Dualtimer:
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* -Timer1 as the free running timer
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* -Timer2 as the interval timer
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* Both timers are set:
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* -32 bit size
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* -256 Clk divisor
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* -Maximum reload value
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*/
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void lp_ticker_init(void)
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{
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dualtimer_cmsdk_init(&LP_TIMER_DEV);
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dualtimer_cmsdk_set_size_both_timers(&LP_TIMER_DEV,
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DUALTIMER_CMSDK_SIZE_32BIT);
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dualtimer_cmsdk_set_prescale_both_timers(&LP_TIMER_DEV,
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DUALTIMER_CMSDK_CLOCK_DIV256);
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dualtimer_cmsdk_disable_both_timers(&LP_TIMER_DEV);
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dualtimer_cmsdk_set_reload_both_timers(&LP_TIMER_DEV,
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TIMER_CMSDK_MAX_RELOAD);
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dualtimer_cmsdk_reset_both_timers(&LP_TIMER_DEV);
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NVIC_EnableIRQ(LP_INTERVAL_IRQ);
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dualtimer_cmsdk_enable_both_timers(&LP_TIMER_DEV);
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}
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void lp_ticker_free(void)
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{
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dualtimer_cmsdk_free(&LP_TIMER_DEV);
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}
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uint32_t lp_ticker_read()
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{
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uint32_t tick = dualtimer_cmsdk_get_elapsed_value_timer1(&LP_TIMER_DEV);
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last_read = tick >> LP_REPORTED_SHIFT;
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return last_read;
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}
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void lp_ticker_set_interrupt(timestamp_t timestamp)
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{
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uint32_t reload = (timestamp - last_read) << LP_REPORTED_SHIFT;
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dualtimer_cmsdk_disable_timer2(&LP_TIMER_DEV);
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dualtimer_cmsdk_set_reload_timer2(&LP_TIMER_DEV, reload);
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dualtimer_cmsdk_reset_timer2(&LP_TIMER_DEV);
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dualtimer_cmsdk_enable_interrupt_timer2(&LP_TIMER_DEV);
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dualtimer_cmsdk_enable_timer2(&LP_TIMER_DEV);
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}
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void lp_ticker_disable_interrupt(void)
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{
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dualtimer_cmsdk_disable_interrupt_timer2(&LP_TIMER_DEV);
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}
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void lp_ticker_clear_interrupt(void)
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{
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dualtimer_cmsdk_clear_interrupt_timer2(&LP_TIMER_DEV);
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}
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void lp_ticker_fire_interrupt(void)
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{
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NVIC_SetPendingIRQ(LP_INTERVAL_IRQ);
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}
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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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LP_REPORTED_FREQ_HZ,
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LP_REPORTED_BITS
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};
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return &info;
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}
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#ifndef lp_interval_irq_handler
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#error "lp_interval_irq_handler should be defined, check device_cfg.h!"
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#endif
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/* According to mbed's specification, the free running timer shouldn't fire
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* interrupt, since the upper layer polls that and handles the overflow,
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* by cumulating the read values.
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*/
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void lp_interval_irq_handler(void)
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{
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lp_ticker_disable_interrupt();
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lp_ticker_irq_handler();
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}
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