RV5C387A_03 datasheet(8/49 Pages) RICOH

Part #	RV5C387A

Description	I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC WITH VOLTAGE MONITORING FUNCTION

Download	49 Pages

Scroll/Zoom	100%

Manufacturer	RICOH [RICOH electronics devices division]

Direct Link	http://www.ricoh.com

Logo

8 / 49 page

RV5C387A

8

5. Oscillation Halt Sensing Function and Supply Voltage Monitoring Function

The RV5C387A incorporates an oscillation halt sensing circuit equipped with internal registers configured to record

any past oscillation halt, thereby identifying whether they are powered on from 0 volts or battery backed-up. As

such, the oscillation halt sensing circuit is useful for judging the validity of time data.

The RV5C387A also incorporates a supply voltage monitoring circuit equipped with internal registers configured to

record any drop in supply voltage below a certain threshold value. Supply voltage monitoring threshold settings can

be selected between 2.1 and 1.6 volts through internal register settings.

The oscillation halt sensing circuit is configured to confirm the established invalidation of time data in contrast to

the supply voltage monitoring circuit intended to confirm the potential invalidation of time data. Further, the supply

voltage monitoring circuit can be applied to battery supply voltage monitoring.

6. Periodic Interrupt Function

The RV5C387A incorporates a periodic interrupt circuit configured to generate periodic interrupt signals aside from

interrupt signals generated by the alarm circuit for output from the INTRA pin. Periodic interrupt signals have five

selectable frequency settings of 2Hz (once per 0.5 seconds), 1Hz (once per 1 second), 1/60Hz (once per 1 minute),

1/3600Hz (once per 1 hour), and monthly (the first day of every month). Further, periodic interrupt signals also

have two selectable waveforms of a normal pulse form (with a frequency of 2Hz or 1Hz) and special form adapted to

interruption from the CPU in the level mode (with second, minute, hour, and month interrupts). The register

records of periodic interrupt signals can be monitored by using a polling function.

7. 32-kHz Clock Output Function

The RV5C387A incorporates a 32-kHz clock circuit configured to generate clock pulses with the oscillation frequen-

cy of a 32.768-kHz crystal oscillator for output from the 32KOUT pin. The 32KOUT pin is Nch. open drain output.

The 32-kHz clock output can be disabled by certain register settings. But it cannot be disabled without manipulation

of any two registers with different addresses, to prevent disabling in such events as the runaway of the CPU. The

32-kHz clock circuit is enabled at power-on.

Similar Part No. - RV5C387A_03

Manufacturer	Part #	Datasheet	Description
RICOH electronics devic...	RV5C387A-E2	363Kb / 42P	I2C-bus Real-Time Clock ICs with Voltage Monitoring Function?

Manufacturer	Part #	Datasheet	Description
RICOH electronics devic...	RV5C386A	377Kb / 49P	I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC WITH VOLTAGE MONITORING FUNCTION
	RV5C387A	363Kb / 42P	I2C-bus Real-Time Clock ICs with Voltage Monitoring Function?
	RS5C372B-E2-F	402Kb / 57P	I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
	RV5C386A	362Kb / 42P	I2C-bus Real-Time Clock ICs with Voltage Monitoring Function
	RS5C372A-E2-F	402Kb / 57P	I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
	RV5C339A	364Kb / 46P	3-WIRE SERIAL INTERFACE REAL-TIME CLOCK IC WITH VOLTAGE MONITORING FUNCTION
	RV5C338A	440Kb / 52P	3-WIRE SERIAL INTERFACE REAL-TIME CLOCK ICs WITH VOLTAGE MONITORING FUNCTION?
	RV5C339A	421Kb / 51P	3-WIRE SERIAL INTERFACE REAL-TIME CLOCK ICs WITH VOLTAGE MONITORING FUNCTION???
	RS5C348A	452Kb / 53P	4-WIRE SERIAL INTERFACE REAL-TIME CLOCK ICs WITH VOLTAGE MONITORING FUNCTION?
	RS5C338A	578Kb / 51P	3-WIRE SERIAL INTERFACE REAL-TIME CLOCK ICs WITH VOLTAGE MONITORING FUNCTION