232 lines
6.9 KiB
C
232 lines
6.9 KiB
C
/******************************************************************************
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* The MIT License
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*
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* Copyright (c) 2012 LeafLabs, LLC.
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*****************************************************************************/
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/**
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* @file rtc.c
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* @author Rod Gilchrist <rod@visibleassets.com>
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* @brief Real Time Clock interface
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*/
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#include "rtc_util.h"
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#define NR_RTC_HANDLERS 4
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static rtc_dev rtc = {
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.regs = RTC_BASE,
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.handlers = { [NR_RTC_HANDLERS - 1] = 0 },
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};
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rtc_dev *RTC = &rtc;
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/**
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* Initialize the RTC interface, and enable access to its register map and
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* the backup registers.
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*/
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void rtc_init(rtc_clk_src src) {
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bkp_init(); // turn on peripheral clocks to PWR and BKP and reset the backup domain via RCC registers.
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// (we reset the backup domain here because we must in order to change the rtc clock source).
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bkp_enable_writes(); // enable writes to the backup registers and the RTC registers via the DBP bit in the PWR control register
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RCC_BASE->BDCR &= ~RCC_BDCR_RTCSEL;
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switch (src) {
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case RTCSEL_NONE:
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RCC_BASE->BDCR = RCC_BDCR_RTCSEL_NONE;
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break;
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case RTCSEL_LSE:
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rcc_start_lse();
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RCC_BASE->BDCR |= RCC_BDCR_RTCSEL_LSE;
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break;
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case RTCSEL_LSI:
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case RTCSEL_DEFAULT:
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rcc_start_lsi();
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RCC_BASE->BDCR |= RCC_BDCR_RTCSEL_LSI;
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break;
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case RTCSEL_HSE: // This selection uses HSE/128 as the RTC source (i.e. 64 kHz with an 8 mHz xtal)
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rcc_start_hse();
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RCC_BASE->BDCR |= RCC_BDCR_RTCSEL_HSE;
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break;
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}
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bb_peri_set_bit(&RCC_BASE->BDCR, RCC_BDCR_RTCEN_BIT, 1); // Enable the RTC
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rtc_clear_sync();
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rtc_wait_sync();
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rtc_wait_finished();
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}
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/**
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* @brief Attach a RTC interrupt.
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* @param interrupt Interrupt number to attach to; this may be any rtc_interrupt_id.
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* @param handler Handler to attach to the given interrupt.
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* @see rtc_interrupt_id
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*/
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void rtc_attach_interrupt( uint8 interrupt,
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voidFuncPtr handler) {
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RTC->handlers[interrupt] = handler;
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rtc_enable_irq(interrupt);
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switch (interrupt) {
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case RTC_SECONDS_INTERRUPT: nvic_irq_enable(NVIC_RTC); break;
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case RTC_OVERFLOW_INTERRUPT: nvic_irq_enable(NVIC_RTC); break;
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case RTC_ALARM_GLOBAL_INTERRUPT: nvic_irq_enable(NVIC_RTC); break;
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case RTC_ALARM_SPECIFIC_INTERRUPT: nvic_irq_enable(NVIC_RTCALARM); break; // The alarm specific interrupt can wake us from deep sleep.
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}
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}
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/**
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* @brief Detach an rtc interrupt.
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* @param interrupt Interrupt number to detach.
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* @see rtc_interrupt_id
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*/
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void rtc_detach_interrupt(uint8 interrupt) {
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rtc_disable_irq(interrupt);
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RTC->handlers[interrupt] = NULL;
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}
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/*
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* IRQ handlers
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*/
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/* For dispatch routines which service multiple interrupts. */
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#define handle_irq(dier_sr, irq_mask, handlers, iid, handled_irq) do { \
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if ((dier_sr) & (irq_mask)) { \
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void (*__handler)(void) = (handlers)[iid]; \
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if (__handler) { \
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__handler(); \
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handled_irq |= (irq_mask); \
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} \
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} \
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} while (0)
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static inline void dispatch_multiple_rtc_irq() {
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rtc_reg_map *regs = RTC->regs;
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uint32 dsr = regs->CRH & regs->CRL;
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void (**hs)(void) = RTC->handlers;
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uint32 handled = 0;
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handle_irq(dsr, RTC_CRL_SECF, hs, RTC_SECONDS_INTERRUPT, handled);
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handle_irq(dsr, RTC_CRL_ALRF, hs, RTC_ALARM_GLOBAL_INTERRUPT, handled);
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handle_irq(dsr, RTC_CRL_OWF, hs, RTC_OVERFLOW_INTERRUPT, handled);
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regs->CRL &= ~handled;
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}
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void __irq_rtc(void) {
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dispatch_multiple_rtc_irq();
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}
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/* A special-case dispatch routine for single-interrupt NVIC lines.
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* This function assumes that the interrupt corresponding to `RTC_ALARM_INTERRUPT' has
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* in fact occurred (i.e., it doesn't check DIER & SR). */
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void __irq_rtcalarm(void) {
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void (*handler)(void) = RTC->handlers[RTC_ALARM_SPECIFIC_INTERRUPT];
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if (handler) {
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handler();
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*bb_perip(&EXTI_BASE->PR, EXTI_RTC_ALARM_BIT) = 1;
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//asm volatile("nop"); // See comment in exti.c. Doesn't seem to be required.
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//asm volatile("nop");
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}
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}
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/**
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* @brief Returns the rtc's counter (i.e. time/date) value.
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*
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* This value is likely to be inaccurate if the counter is running
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* with a low prescaler.
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*/
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uint32 rtc_get_count() {
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uint32 h, l;
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rtc_clear_sync();
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rtc_wait_sync();
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rtc_wait_finished();
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h = RTC->regs->CNTH & 0xffff;
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l = RTC->regs->CNTL & 0xffff;
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return (h << 16) | l;
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}
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/**
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* @brief Sets the counter value (i.e. time/date) for the rtc.
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* @param value New counter value
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*/
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void rtc_set_count(uint32 value) {
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rtc_clear_sync();
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rtc_wait_sync();
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rtc_wait_finished();
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rtc_enter_config_mode();
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RTC->regs->CNTH = (value >> 16) & 0xffff;
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RTC->regs->CNTL = value & 0xffff;
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rtc_exit_config_mode();
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rtc_wait_finished();
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}
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/**
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* @brief Sets the prescaler load value for the rtc.
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* @param value New prescaler load value (use 0x7fff to get 1 second period with 32.768 Hz clock).
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*/
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void rtc_set_prescaler_load(uint32 value) {
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rtc_clear_sync();
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rtc_wait_sync();
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rtc_wait_finished();
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rtc_enter_config_mode();
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RTC->regs->PRLH = (value >> 16) & 0xffff;
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RTC->regs->PRLL = value & 0xffff;
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rtc_exit_config_mode();
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rtc_wait_finished();
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}
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/**
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* @brief Returns the rtc's prescaler divider (i.e. current divider count) value.
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*/
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uint32 rtc_get_divider() {
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uint32 h, l;
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rtc_clear_sync();
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rtc_wait_sync();
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rtc_wait_finished();
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h = RTC->regs->DIVH & 0x000f;
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l = RTC->regs->DIVL & 0xffff;
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return (h << 16) | l;
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}
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/**
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* @brief Sets the alarm value (i.e. time/date) for the rtc.
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* @param value New alarm value
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*/
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void rtc_set_alarm(uint32 value) {
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rtc_clear_sync();
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rtc_wait_sync();
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rtc_wait_finished();
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rtc_enter_config_mode();
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RTC->regs->ALRH = (value >> 16) & 0xffff;
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RTC->regs->ALRL = value & 0xffff;
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rtc_exit_config_mode();
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rtc_wait_finished();
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} |