R×5C348A/B
PIN DESCRIPTIONS
Pin No. Symbol
Item
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 regardless of supply
voltage.
7
CE
Chip Enable Input
The SCLK pin is used to input clock pulses synchronizing the input and output of
data to and from the SI and SO pins. Allows a maximum input voltage of 5.5 volts
regardless of supply voltage.
2
4
SCLK
SI
Serial Clock Input
Serial Input
The SI pin is used to input data intended for writing in synchronization with the
SCLK pin. CMOS input. Allows a maximum input voltage of 5.5 volts regardless of
supply voltage.
The SO pin is used to output data intended for reading in synchronization with the
SCLK pin. CMOS output.
3
6
SO
Serial Output
The INTR pin is used to output periodic interrupt signals to the CPU and alarm
interrupt signals. Disabled at power-on from 0 volts. Nch. open drain output.
INTR
Interrupt Output
The 32KOUT pin is used to output 32.768-kHz clock pulses. Enabled at power-on
from 0 volts. Nch. open drain output. The R×5C348A is designed to be disabled
32-kHz clock output in response to a command from the host computer and the
R×5C348B is designed to keep 32-kHz output enabled.
1
32KOUT 32-kHz Clock Output
The OSCIN and OSCOUT pins are used to connect the 32.768-kHz crystal
oscillator (with all other oscillation circuit components built into the
R×5C348A/B).
9
8
OSCIN
Oscillatory Circuit
OSCOUT Input/Output
10
5
VDD
VSS
Positive Power Supply Input
Negative Power Supply Input
The VDD pin is connected to the power supply. The VSS pin is grounded.
3
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
