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
7
CE
Chip Enable Input
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.
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 SI and SO pins. Allows a maximum input voltage of 5.5 volts
regardless of supply voltage.
The SI pin is used to input data intended for writing in synchronization with the
4
SI
Serial Input
SCLK pin. CMOS input. Allows a maximum input voltage of 5.5 volts regardless of
supply voltage.
3
SO
Serial Output
The SO pin is used to output data intended for reading in synchronization with the
SCLK pin. CMOS 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.
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 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.
9
8
10
5
OSCIN
OSCOUT
VDD
VSS
Oscillatory Circuit
Input/Output
Positive Power Supply Input
Negative Power Supply Input
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).
The VDD pin is connected to the power supply. The VSS pin is grounded.
6
INTR
Interrupt Output
3
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
