122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
/** @file bkp.h
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* Module handling the Backup (BKP) domain functionalities.
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*
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* This module includes management of the Real Time Clock (RTC), Tamper
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* protection system and a limited space (20 bytes) for persistent data storage
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*
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* All features present in this module stay running in standby mode / when
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* no-longer powered, so long as VBAT is maintained
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*/
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#ifndef _BKP_H_
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#define _BKP_H_
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//--includes--------------------------------------------------------------------
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#include "stdint.h"
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#include "tim.h"
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//--type definitions------------------------------------------------------------
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/**
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* Available clock sources for the RTC. See bkp_configure_rtc() for more
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* information
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*/
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enum BkpRtcClockSrc {
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BKP_RTC_CLOCK_SRC_LSE = 0x0,
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BKP_RTC_CLOCK_SRC_LSI = 0x1,
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BKP_RTC_CLOCK_SRC_HSE = 0x2,
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};
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/**
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* Available IRQ sources. This enum is passed to the RTC callback to allow
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* differentiating IRQ sources
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*/
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enum BkpRtcIrq {
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BKP_RTC_IRQ_NONE = 0,
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BKP_RTC_IRQ_SECOND = 0x1 << 0,
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BKP_RTC_IRQ_ALARM = 0x1 << 1,
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BKP_RTC_IRQ_OVERFLOW = 0x1 << 2,
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};
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enum BkpData {
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BKP_DATA_LSI_CALIB,
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BKP_DATA_1,
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BKP_DATA_2,
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BKP_DATA_3,
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BKP_DATA_4,
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BKP_DATA_5,
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BKP_DATA_6,
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BKP_DATA_7,
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BKP_DATA_8,
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BKP_DATA_9,
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};
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/**
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* Prototype of the IRQ callbacks that the applicative code can provide
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*/
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typedef void (*BkpRtcCallback)(enum BkpRtcIrq src);
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//--functions-------------------------------------------------------------------
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/**
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* Configures the RTC, starting it immediately. Configuration is saved between
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* boots as long as VBAT is present
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*
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* The RTC can run on a period of up to 1s and using one of 3 clocks. Clock
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* choice is a question of compromise :
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* - LSE consumes the less energy and continues to run in standby mode, but
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* requires an extra oscillator circuit
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* - LSI consumes little but isn't very accurate and requires extra calibration
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* (see bkp_callibrate_lsi)
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* - HSE consumes the most.
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* WARNING : once configured, the clock source can only changed by reseting the
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* whole backup domain via bkp_reset()
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* Clocks must be enabled prior to calling this function
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*
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* Mulitple IRQs can be enabled and redirected to single callback. The alarm
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* IRQ, triggered at the tick value specified by bkp_set_rtc_alam() can be
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* rerouted to an exti line for wakeup from stop and standby, in wich case it
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* doesn't need to be enabled here.
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*
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* Ensure backup domain writes are enabled (see pwr_configure_bkp_write()) while
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* calling this function
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*/
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void bkp_configure_rtc(uint32_t period_ms, enum BkpRtcClockSrc clock_src,
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enum BkpRtcIrq irq_mask, BkpRtcCallback callback);
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/**
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* Configure the alarm to trigger after the specified time in ticks, which can
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* be viewed as an offset to the current time value. This offset is only precise
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* to the tick and thus if the tick changes right after this function is
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* called, the observed offset will be close to 1 tick short
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*/
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void bkp_set_rtc_alam(uint32_t offset);
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/**
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* Returns the current counter value of the RTC
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*/
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uint32_t bkp_read_rtc(void);
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uint32_t bkp_read_rtc_div(void);
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/**
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* Resets the entire backup domain, composed of everything configured through
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* this module
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*/
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void bkp_reset(void);
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void bkp_write_data(enum BkpData data_index, uint16_t data);
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uint16_t bkp_read_data(enum BkpData data_index);
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void bkp_calibrate_lsi(enum TimPeriph timer);
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//unimplemented functions
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void bkp_configure_tamper();
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void bkp_configure_lse(bool enable);
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#endif //_BKP_H_
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