Mouse code for the MacroRat
Diff: mbed-dev/targets/TARGET_Silicon_Labs/TARGET_EFM32/lp_ticker.c
- Revision:
- 18:6a4db94011d3
diff -r f713758f6238 -r 6a4db94011d3 mbed-dev/targets/TARGET_Silicon_Labs/TARGET_EFM32/lp_ticker.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-dev/targets/TARGET_Silicon_Labs/TARGET_EFM32/lp_ticker.c Sun May 14 23:18:57 2017 +0000 @@ -0,0 +1,193 @@ +/***************************************************************************//** + * @file lp_ticker.c + ******************************************************************************* + * @section License + * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b> + ******************************************************************************* + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed under the Apache License, Version 2.0 (the "License"); you may + * not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + ******************************************************************************/ + +#include "device.h" +#include "clocking.h" +#if DEVICE_LOWPOWERTIMER + +#include "rtc_api.h" +#include "rtc_api_HAL.h" +#include "lp_ticker_api.h" + +#include "mbed_critical.h" +#if (defined RTCC_COUNT) && (RTCC_COUNT > 0) +#include "em_rtcc.h" +#endif + +static int rtc_reserved = 0; + +void lp_ticker_init() +{ + if(!rtc_reserved) { + core_util_critical_section_enter(); + rtc_init_real(RTC_INIT_LPTIMER); + rtc_set_comp0_handler((uint32_t)lp_ticker_irq_handler); + rtc_reserved = 1; + core_util_critical_section_exit(); + } +} + +void lp_ticker_free() +{ + if(rtc_reserved) { + core_util_critical_section_enter(); + rtc_free_real(RTC_INIT_LPTIMER); + rtc_reserved = 0; + core_util_critical_section_exit(); + } +} + +#ifndef RTCC_COUNT + +/* RTC API */ + +void lp_ticker_set_interrupt(timestamp_t timestamp) +{ + uint64_t timestamp_ticks; + uint64_t current_ticks = RTC_CounterGet(); + timestamp_t current_time = ((uint64_t)(current_ticks * 1000000) / (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT)); + + /* Initialize RTC */ + lp_ticker_init(); + + /* calculate offset value */ + timestamp_t offset = timestamp - current_time; + if(offset > 0xEFFFFFFF) offset = 100; + + /* map offset to RTC value */ + // ticks = offset * RTC frequency div 1000000 + timestamp_ticks = ((uint64_t)offset * (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT)) / 1000000; + timestamp_ticks += current_ticks; + + /* RTC has 24 bit resolution */ + timestamp_ticks &= 0xFFFFFF; + + /* check for RTC limitation */ + if((timestamp_ticks - RTC_CounterGet()) >= 0x800000) timestamp_ticks = RTC_CounterGet() + 2; + + /* Set callback */ + RTC_FreezeEnable(true); + RTC_CompareSet(0, (uint32_t)timestamp_ticks); + RTC_IntEnable(RTC_IF_COMP0); + RTC_FreezeEnable(false); +} + +inline void lp_ticker_disable_interrupt() +{ + RTC_IntDisable(RTC_IF_COMP0); + lp_ticker_free(); +} + +inline void lp_ticker_clear_interrupt() +{ + RTC_IntClear(RTC_IF_COMP0); +} + +timestamp_t lp_ticker_read() +{ + lp_ticker_init(); + + uint64_t ticks_temp; + uint64_t ticks = RTC_CounterGet(); + + /* ticks = counter tick value + * timestamp = value in microseconds + * timestamp = ticks * 1.000.000 / RTC frequency + */ + + ticks_temp = (ticks * 1000000) / (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT); + return (timestamp_t) (ticks_temp & 0xFFFFFFFF); +} + +#else + +/* RTCC API */ + +void lp_ticker_set_interrupt(timestamp_t timestamp) +{ + uint64_t timestamp_ticks; + uint64_t current_ticks = RTCC_CounterGet(); + timestamp_t current_time = ((uint64_t)(current_ticks * 1000000) / (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT)); + + /* Initialize RTC */ + lp_ticker_init(); + + /* calculate offset value */ + timestamp_t offset = timestamp - current_time; + if(offset > 0xEFFFFFFF) offset = 100; + + /* map offset to RTC value */ + // ticks = offset * RTC frequency div 1000000 + timestamp_ticks = ((uint64_t)offset * (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT)) / 1000000; + // checking the rounding. If timeout is wanted between RTCC ticks, irq should be configured to + // trigger in the latter RTCC-tick. Otherwise ticker-api fails to send timer event to its client + if(((timestamp_ticks * 1000000) / (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT)) < offset){ + timestamp_ticks++; + } + + timestamp_ticks += current_ticks; + + /* RTCC has 32 bit resolution */ + timestamp_ticks &= 0xFFFFFFFF; + + /* check for RTCC limitation */ + if((timestamp_ticks - RTCC_CounterGet()) >= 0x80000000) timestamp_ticks = RTCC_CounterGet() + 2; + + /* init channel */ + RTCC_CCChConf_TypeDef ccchConf = RTCC_CH_INIT_COMPARE_DEFAULT; + RTCC_ChannelInit(0,&ccchConf); + /* Set callback */ + RTCC_ChannelCCVSet(0, (uint32_t)timestamp_ticks); + RTCC_IntEnable(RTCC_IF_CC0); +} + +inline void lp_ticker_disable_interrupt() +{ + RTCC_IntDisable(RTCC_IF_CC0); + lp_ticker_free(); +} + +inline void lp_ticker_clear_interrupt() +{ + RTCC_IntClear(RTCC_IF_CC0); +} + +timestamp_t lp_ticker_read() +{ + lp_ticker_init(); + + uint64_t ticks_temp; + uint64_t ticks = RTCC_CounterGet(); + + /* ticks = counter tick value + * timestamp = value in microseconds + * timestamp = ticks * 1.000.000 / RTC frequency + */ + + ticks_temp = (ticks * 1000000) / (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT); + return (timestamp_t) (ticks_temp & 0xFFFFFFFF); +} + +#endif /* RTCC */ + +#endif