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targets/TARGET_Maxim/TARGET_MAX32630/rtc_api.c
- Committer:
- amithy
- Date:
- 2017-11-09
- Revision:
- 178:c26431f84b0d
- Parent:
- 157:ff67d9f36b67
- Child:
- 165:e614a9f1c9e2
File content as of revision 178:c26431f84b0d:
/******************************************************************************* * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. * * Except as contained in this notice, the name of Maxim Integrated * Products, Inc. shall not be used except as stated in the Maxim Integrated * Products, Inc. Branding Policy. * * The mere transfer of this software does not imply any licenses * of trade secrets, proprietary technology, copyrights, patents, * trademarks, maskwork rights, or any other form of intellectual * property whatsoever. Maxim Integrated Products, Inc. retains all * ownership rights. ******************************************************************************* */ #include "rtc_api.h" #include "lp_ticker_api.h" #include "rtc.h" #include "lp.h" #define PRESCALE_VAL RTC_PRESCALE_DIV_2_0 // Set the divider for the 4kHz clock #define SHIFT_AMT (RTC_PRESCALE_DIV_2_12 - PRESCALE_VAL) #define WINDOW 1000 static int rtc_inited = 0; static volatile uint32_t overflow_cnt = 0; static uint64_t rtc_read64(void); //****************************************************************************** static void overflow_handler(void) { overflow_cnt++; RTC_ClearFlags(MXC_F_RTC_FLAGS_ASYNC_CLR_FLAGS); } //****************************************************************************** void rtc_init(void) { if (rtc_inited) { return; } rtc_inited = 1; overflow_cnt = 0; /* Enable power for RTC for all LPx states */ MXC_PWRSEQ->reg0 |= (MXC_F_PWRSEQ_REG0_PWR_RTCEN_RUN | MXC_F_PWRSEQ_REG0_PWR_RTCEN_SLP); /* Enable clock to synchronizers */ CLKMAN_SetClkScale(CLKMAN_CLK_SYNC, CLKMAN_SCALE_DIV_1); // Prepare interrupt handlers NVIC_SetVector(RTC0_IRQn, lp_ticker_irq_handler); NVIC_EnableIRQ(RTC0_IRQn); NVIC_SetVector(RTC3_IRQn, overflow_handler); NVIC_EnableIRQ(RTC3_IRQn); // Enable wakeup on RTC rollover LP_ConfigRTCWakeUp(0, 0, 0, 1); /* RTC registers are only reset on a power cycle. Do not reconfigure the RTC * if it is already running. */ if (!RTC_IsActive()) { rtc_cfg_t cfg = {0}; cfg.prescaler = PRESCALE_VAL; cfg.snoozeMode = RTC_SNOOZE_DISABLE; int retval = RTC_Init(&cfg); MBED_ASSERT(retval == E_NO_ERROR); RTC_EnableINT(MXC_F_RTC_FLAGS_OVERFLOW); RTC_Start(); } } //****************************************************************************** void lp_ticker_init(void) { rtc_init(); } //****************************************************************************** void rtc_free(void) { if (RTC_IsActive()) { // Clear and disable RTC MXC_RTCTMR->ctrl |= MXC_F_RTC_CTRL_CLEAR; RTC_Stop(); } } //****************************************************************************** int rtc_isenabled(void) { return RTC_IsActive(); } //****************************************************************************** time_t rtc_read(void) { uint32_t ovf_cnt_1, ovf_cnt_2, timer_cnt; uint32_t ovf1, ovf2; // Make sure RTC is setup before trying to read if (!rtc_inited) { rtc_init(); } // Ensure coherency between overflow_cnt and timer do { ovf_cnt_1 = overflow_cnt; ovf1 = RTC_GetFlags() & MXC_F_RTC_FLAGS_OVERFLOW; timer_cnt = RTC_GetCount(); ovf2 = RTC_GetFlags() & MXC_F_RTC_FLAGS_OVERFLOW; ovf_cnt_2 = overflow_cnt; } while ((ovf_cnt_1 != ovf_cnt_2) || (ovf1 != ovf2)); // Account for an unserviced interrupt if (ovf1) { ovf_cnt_1++; } return (timer_cnt >> SHIFT_AMT) + (ovf_cnt_1 << (32 - SHIFT_AMT)); } //****************************************************************************** static uint64_t rtc_read64(void) { uint32_t ovf_cnt_1, ovf_cnt_2, timer_cnt; uint32_t ovf1, ovf2; uint64_t current_us; // Make sure RTC is setup before trying to read if (!rtc_inited) { rtc_init(); } // Ensure coherency between overflow_cnt and timer do { ovf_cnt_1 = overflow_cnt; ovf1 = RTC_GetFlags() & MXC_F_RTC_FLAGS_OVERFLOW; timer_cnt = RTC_GetCount(); ovf2 = RTC_GetFlags() & MXC_F_RTC_FLAGS_OVERFLOW; ovf_cnt_2 = overflow_cnt; } while ((ovf_cnt_1 != ovf_cnt_2) || (ovf1 != ovf2)); // Account for an unserviced interrupt if (ovf1) { ovf_cnt_1++; } current_us = (((uint64_t)timer_cnt * 1000000) >> SHIFT_AMT) + (((uint64_t)ovf_cnt_1 * 1000000) << (32 - SHIFT_AMT)); return current_us; } //****************************************************************************** void rtc_write(time_t t) { // Make sure RTC is setup before accessing if (!rtc_inited) { rtc_init(); } RTC_Stop(); RTC_SetCount(t << SHIFT_AMT); overflow_cnt = t >> (32 - SHIFT_AMT); RTC_Start(); } //****************************************************************************** void lp_ticker_set_interrupt(timestamp_t timestamp) { uint32_t comp_value; uint64_t curr_ts64; uint64_t ts64; // Note: interrupts are disabled before this function is called. // Disable the alarm while it is prepared RTC_DisableINT(MXC_F_RTC_INTEN_COMP0); curr_ts64 = rtc_read64(); ts64 = (uint64_t)timestamp | (curr_ts64 & 0xFFFFFFFF00000000ULL); // If this event is older than a recent window, it must be in the future if ((ts64 < (curr_ts64 - WINDOW)) && ((curr_ts64 - WINDOW) < curr_ts64)) { ts64 += 0x100000000ULL; } uint32_t timer = RTC_GetCount(); if (ts64 <= curr_ts64) { // This event has already occurred. Set the alarm to expire immediately. comp_value = timer + 1; } else { comp_value = (ts64 << SHIFT_AMT) / 1000000; } // Ensure that the compare value is far enough in the future to guarantee the interrupt occurs. if ((comp_value < (timer + 2)) && (comp_value > (timer - 10))) { comp_value = timer + 2; } MXC_RTCTMR->comp[0] = comp_value; MXC_RTCTMR->flags = MXC_F_RTC_FLAGS_ASYNC_CLR_FLAGS; RTC_EnableINT(MXC_F_RTC_INTEN_COMP0); // Enable wakeup from RTC LP_ConfigRTCWakeUp(1, 0, 0, 1); // Wait for pending transactions while (MXC_RTCTMR->ctrl & MXC_F_RTC_CTRL_PENDING); } //****************************************************************************** inline void lp_ticker_disable_interrupt(void) { RTC_DisableINT(MXC_F_RTC_INTEN_COMP0); } //****************************************************************************** inline void lp_ticker_clear_interrupt(void) { RTC_ClearFlags(MXC_F_RTC_FLAGS_ASYNC_CLR_FLAGS); } //****************************************************************************** inline uint32_t lp_ticker_read(void) { return rtc_read64(); }