RTC RV-3028-C7 Arduino Library

Application Manual

The RV-3028-C7 is an extremely precise, extremely low power, highly configurable RTC. Under ideal conditions it runs at approximately 40nA with +/-5ppm per year of deviation (+/- 160 seconds worst case per year). This library was originally forked from the Sparkfun RV-1805 library, and costumized and enhanced to the RV-3028-C7.

This library allows the user to:

• Set time using hard numbers or the BUILD_TIME from the Arduino compiler
• Read time
• Configure various aspects of the RTC including setting of alarms, countdown timers, periodic time update interrupts, trickle charging, power switchover mode and programmable clock output.

Examples are included to get you started (but still missing for CountdownTimer, PeriodicTimeUpdate Interrupt and Programmable Clock Output).

Repository Contents

• /examples - Example sketches for the library (.ino). Run these from the Arduino IDE.
• /src - Source files for the library (.cpp, .h).
• keywords.txt - Keywords from this library that will be highlighted in the Arduino IDE.
• library.properties - General library properties for the Arduino package manager.

Documentation

The library enables the following functions:

General functions

Please call begin() sometime after initializing the I2C interface with Wire.begin().

begin()

is12Hour()

isPM()

set12Hour()

set24Hour()

reset()

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Interrupt status

status()

clearInterrupts()

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Set Time functions

setTime(sec, min, hour, weekday, date, month, year);

setSeconds(value)

setMinutes(value)

setHours(value)

setWeekday(value)

setDate(value)

setMonth(value)

setYear(value)

setToCompilerTime()

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Get Time functions

Please call "updateTime()" before calling one of the other getTime functions.

updateTime()

getSeconds()

getMinutes()

getHours()

getWeekday()

getDate()

getMonth()

getYear()

stringDateUSA()

stringDate()

stringTime()

stringTimeStamp()

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UNIX Time functions

Attention: UNIX Time and real time are INDEPENDENT!

setUNIX(value)

getUNIX()

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Alarm Interrupt functions

enableAlarmInterrupt(min, hour, date_or_weekday, bool setWeekdayAlarm_not_Date, mode, bool enable_clock_output = false)

disableAlarmInterrupt()

readAlarmInterruptFlag()

clearAlarmInterruptFlag()

Set the alarm mode in the following way:
0: When minutes, hours and weekday/date match (once per weekday/date)
1: When hours and weekday/date match (once per weekday/date)
2: When minutes and weekday/date match (once per hour per weekday/date)
3: When weekday/date match (once per weekday/date)
4: When hours and minutes match (once per day)
5: When hours match (once per day)
6: When minutes match (once per hour)
7: All disabled – Default value
If you want to set a weekday alarm (setWeekdayAlarm_not_Date = true), set date_or_weekday from 0 (Sunday) to 6 (Saturday).
For further information about the alarm mode see Application Manual p. 68.

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Countdown Timer Interrupt functions

Thanks @JasonEdinburgh for this enhancement.

setTimer(bool timer_repeat, uint16_t timer_frequency, uint16_t timer_value, bool setInterrupt, bool start_timer, bool enable_clock_output = false)

enableTimer()

disableTimer()

enableTimerInterrupt()

disableTimerInterrupt()

readTimerInterruptFlag()

clearTimerInterruptFlag()

timer_repeat specifies either Single or Repeat Mode for the Periodic Countdown Timer.
Setting of timer_frequency:

timer_frequency		error on first time	max. duration (timer_value = 4095)
4096 (default)	4096Hz	122us	0.9998s
64	64Hz	7.813ms	63.984s
1	1Hz	7.813ms	4095s
60000	1/60Hz	7.813ms	4095min

Countdown Period [s] = Timer Value / Timer Frequency
See Application Manual p. 63 for more information.

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Periodic Time Update Interrupt functions

Thanks @JasonEdinburgh for this enhancement.

enablePeriodicUpdateInterrupt(bool every_second, bool enable_clock_output = false)

disablePeriodicUpdateInterrupt()

readPeriodicUpdateInterruptFlag()

clearPeriodicUpdateInterruptFlag()

every_second specifies the interrupt to occur either every second or every minute.

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Trickle Charge functions

enableTrickleCharge(uint8_t tcr = TCR_15K)

disableTrickleCharge()

At "enableTrickleCharge" you can choose the series resistor:
TCR_3K for 3kOhm
TCR_5K for 5kOhm
TCR_9K for 9kOhm
TCR_15K for 15kOhm
See Application Manual p. 48 for more information.

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Backup Switchover Mode

setBackupSwitchoverMode(mode)

0 = Switchover disabled
1 = Direct Switching Mode
2 = Standby Mode
3 = Level Switching Mode
See Application Manual p. 45 for more information.

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Programmable Clock Output

enableClockOut(uint8_t freq)

enableInterruptControlledClockout(uint8_t freq)

disableClockOut()

readClockOutputInterruptFlag()

clearClockOutputInterruptFlag()

Set Clockout Frequency freq as follows:

freq	result
FD_CLKOUT_32k	32.768 kHz
FD_CLKOUT_8192	8192 Hz
FD_CLKOUT_1024	1024 Hz
FD_CLKOUT_64	64 Hz
FD_CLKOUT_32	32 Hz
FD_CLKOUT_1	1 Hz
FD_CLKOUT_TIMER	Predefined periodic countdown timer interrupt
FD_CLKOUT_LOW	CLKOUT = LOW

See Application Manual p. 48 for more information. 'enableInterruptControlledClockout' generally enables the Interrupt Controlled Clockout (required for triggering Clockout at Alarm, PeriodicUpdate and CountdownTimer Interrupts).

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User EEPROM

writeUserEEPROM(uint8_t eepromaddr, uint8_t val)

readUserEEPROM(uint8_t eepromaddr)

License Information

This product is open source!

Please review the LICENSE.md file for license information.

If you have any questions or concerns on licensing, please contact [email protected].

Distributed as-is; no warranty is given.