2 I C bus SERIAL INTERFACE REAL-TIME CLOCK IC WITH VOLTAGE MONITORING FUNCTION RV5C387A OUTLINE The RV5C387A is a CMOS real-time clock IC connected to the CPU by two signal, SCL and SDA, and configured to perform serial transmission of time and calendar data to the CPU. The periodic interrupt circuit is configured to generate interrupt signals with six selectable interrupts ranging from 0.5 seconds to 1 month. The 2 alarm circuits generate interrupt signals at preset times. The oscillation circuit is driven under constant voltage so that fluctuations in oscillation frequency due to voltage are small and supply current is also small (TYP. 0.35A for the RV5C387A at 3 volts). The oscillation halt sensing circuit can be used to judge the validity of internal data in such events as power-on. The supply voltage monitoring circuit is configured to record a drop in supply voltage below two selectable supply voltage monitoring threshold settings. The 32-kHz clock output function (Nch. open drain) is intended to output sub-clock pulses for the external microcomputer. The oscillation adjustment circuit is intended to adjust time counts with high precision by correcting deviations in the oscillation frequency of the crystal oscillator. The 32-kHz clock circuit can be disabled by certain register settings. This model comes in an ultra- compact 10-pin SSOP-G (with a height of 1.20mm and a pin pitch of 0.5mm). FEATURES Timekeeping supply voltage ranging from 1.45 to 5.5 volts Low supply current: TYP. 0.35A (MAX. 0.8A) at 3 volts Only two signal lines (SCL, SDA) required for connection to the CPU. 2 (I C bus compatible, 400kHz at VDD2.5V, address 7bits) Time counters (counting hours, minutes, and seconds) and calendar counters (counting years, months, days, and weeks) (in BCD format) 1900/2000 identification bit for Year 2000 compliance Interrupt circuit configured to generate interrupt signals (with interrupts ranging from 0.5 seconds to 1 month) to the CPU and provided with an interrupt flag and an interrupt halt circuit 2 alarm circuits (Alarm W for week, hour, and minute alarm settings and Alarm D for hour and minute alarm settings) 32-kHz clock circuit (Nch. open drain output) Oscillation halt sensing circuit which can be used to judge the validity of internal data Supply voltage monitoring circuit with two supply voltage monitoring threshold settings Automatic identification of leap years up to the year 2099 Selectable 12-hour and 24-hour mode settings Built-in oscillation stabilization capacitors (CG and CD) High precision oscillation adjustment circuit CMOS process Ultra-compact 10-pin SSOP-G(with a height of 1.20mm and size 4.0mm2.9mm) 1RV5C387A Note 2 I C bus is a trademark of PHILIPS ELECTRONICS N.V. 2 2 Purchase of I C components of Ricoh Company, Ltd. conveys a license under the Philips I C Patent Rights to 2 2 use these components in an I C system, provided that the system comforms to the I C Standard Specification as defined by Philips. BLOCK DIAGRAM ALARM W REGISTER COMPARATOR W 32KOUT 32kHz (MIN,HOUR,WEEK) OUTPUT VDD CONTROL ALARM D REGISTER VOLTAGE COMPARATOR D (MIN,HOUR) DETECT OSCIN DIVIDER VSS TIME COUNTER OSC CORREC DIV (SEC,MIN,HOUR,WEEK,DAY,MONTH,YEAR) -TION OSCOUT SCL OSC ADDRESS ADDRESS DETECT DECODER REGISTER INTRA SDA I/O CONTROL INTRB INTERRUPT CONTROL SHIFT REGISTER INTRC APPLICATIONS Communication devices (multi function phone, portable phone, PHS or pager) OA devices (fax, portable fax) Computer (desk-top and mobile PC, portable word-processor, PDA, electric note or video game) AV components (portable audio unit, video camera,camera, digital camera or remote controller) Home appliances (rice cooker, electric oven) Other (car navigation system, multi-function watch) PIN CONFIGURATION 10-pin SSOP-G 1 10 32KOUT VDD 2 9 OSCIN SCL 3 OSCOUT SDA 8 4 INTRC 7 INTRB VSS 5 6 INTRA 2