RV5C339A Datasheet, PDF (6/51 Pages) RICOH electronics devices division – 3-WIRE SERIAL INTERFACE REAL-TIME CLOCK ICs WITH VOLTAGE MONITORING FUNCTION

RV5C339A
PIN DESCRIPTIONS
Pin No. Symbol
Name
7
CE Chip Enable Input
Description
The CE pin is used for interfacing with the CPU. Should be held high to allow
access to the CPU. Incorporates a pull-down resistor. Should be held low or open
when the CPU is powered off. Allows a maximum input voltage of 5.5 volts regard-
less of supply voltage.
The SCLK pin is used to input clock pulses synchronizing the input and output of
2 SCLK Serial Clock Input data to and from the SIO pin. Allows a maximum input voltage of 5.5 volts regard-
less of supply voltage.
The SIO pin is used to input and output data intended for writing and reading in
3
SIO Serial Input/Output
synchronization with the SCLK pin. CMOS input/output.
The INTRA pin is used to output periodic interrupt signals to the CPU and alarm
6 INTRA Interrupt Output A interrupt signals (Alarm_D). Disabled at power-on from 0 volts.
Nch. open drain output.
The INTRB pin is used to output alarm interrupt signals (Alarm_W). Disable at
4 INTRB Interrupt Output B
power-on from 0 volts. Nch. open drain output.
The 32KOUT pin is used to output 32.768-kHz clock pulses. Enabled at power-on
1 32KOUT 32-kHz Clock Output from 0 volts. Nch. open drain output. The RV5C339A is designed to be disabled
32-kHz clock output in response to a command from the host computer.
9 OSCIN Oscillation Circuit
8 OSCOUT Input/Output
The OSCIN and OSCOUT pins are used to connect the 32.768-kHz crystal oscilla-
tor (with all other oscillation circuit components built into the RV5C339A.)
10 VDD Positive Power Supply Input
The VDD pin is connected to the power supply. The VSS pin is grounded.
5
VSS Negative Power Supply Input
3