/** @addtogroup rtc_file */ /* * This file is part of the libopencm3 project. * * Copyright (C) 2012 Karl Palsson * * This library is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library. If not, see . */ /**@{*/ #include /*---------------------------------------------------------------------------*/ /** @brief Set RTC prescalars. This sets the RTC synchronous and asynchronous prescalars. */ void rtc_set_prescaler(u32 sync, u32 async) { /* * Even if only one of the two fields needs to be changed, * 2 separate write accesses must be performed to the RTC_PRER register. */ RTC_PRER = (sync & RTC_PRER_PREDIV_S_MASK); RTC_PRER |= (async << RTC_PRER_PREDIV_A_SHIFT); } /*---------------------------------------------------------------------------*/ /** @brief Wait for RTC registers to be synchronised with the APB1 bus Time and Date are accessed through shadow registers which must be synchronized */ void rtc_wait_for_synchro(void) { /* Unlock RTC registers */ RTC_WPR = 0xca; RTC_WPR = 0x53; RTC_ISR &= ~(RTC_ISR_RSF); while (!(RTC_ISR & RTC_ISR_RSF)) { ; } /* disable write protection again */ RTC_WPR = 0xff; } /*---------------------------------------------------------------------------*/ /** @brief Unlock write access to the RTC registers */ void rtc_unlock(void) { RTC_WPR = 0xca; RTC_WPR = 0x53; } /*---------------------------------------------------------------------------*/ /** @brief Lock write access to the RTC registers */ void rtc_lock(void) { RTC_WPR = 0xff; } /**@}*/