Datasheet

R8C/24 Group, R8C/25 Group 1. Overview
Rev.3.00 Feb 29, 2008 Page 11 of 51
REJ03B0117-0300
1.6 Pin Functions
Table 1.5 lists Pin Functions.
I: Input O: Output I/O: Input and output
Table 1.5 Pin Functions
Type Symbol I/O Type Description
Power supply input VCC, VSS I Apply 2.2 V to 5.5 V to the VCC pin. Apply 0 V to the VSS pin.
Analog power
supply input
AVCC, AVSS I Power supply for the A/D converter.
Connect a capacitor between AVCC and AVSS.
Reset input
RESET
I Input “L” on this pin resets the MCU.
MODE MODE I Connect this pin to VCC via a resistor.
XIN clock input XIN I These pins are provided for XIN clock generation circuit I/O.
Connect a ceramic resonator or a crystal oscillator between
the XIN and XOUT pins. To use an external clock, input it to
the XIN pin and leave the XOUT pin open.
XIN clock output XOUT O
XCIN clock input XCIN I These pins are provided for XCIN clock generation circuit I/O.
Connect a crystal oscillator between the XCIN and XCOUT
pins. To use an external clock, input it to the XCIN pin and
leave the XCOUT pin open.
XCIN clock output XCOUT O
INT
interrupt input INT0 to INT3
I
INT
interrupt input pins.
INT0
is timer RD input pin. INT1 is timer RA input pin.
Key input interrupt
KI0 to KI3
I Key input interrupt input pins
Timer RA TRAIO I/O Timer RA I/O pin
TRAO O Timer RA output pin
Timer RB TRBO O Timer RB output pin
Timer RD TRDIOA0, TRDIOA1,
TRDIOB0, TRDIOB1,
TRDIOC0, TRDIOC1,
TRDIOD0, TRDIOD1
I/O Timer RD I/O ports
TRDCLK I External clock input pin
Timer RE TREO O Divided clock output pin
Serial interface CLK0, CLK1 I/O Transfer clock I/O pin
RXD0, RXD1 I Serial data input pins
TXD0, TXD1 O Serial data output pins
I
2
C bus interface
SCL I/O Clock I/O pin
SDA I/O Data I/O pin
Clock synchronous
serial I/O with chip
select
SSI I/O Data I/O pin
SCS
I/O Chip-select signal I/O pin
SSCK I/O Clock I/O pin
SSO I/O Data I/O pin
Reference voltage
input
VREF I Reference voltage input pin to A/D converter
A/D converter AN0 to AN11 I Analog input pins to A/D converter
I/O port P0_0 to P0_7,
P1_0 to P1_7,
P2_0 to P2_7,
P3_0, P3_1,
P3_3 to P3_5, P3_7,
P4_3 to P4_5,
P6_0 to P6_7
I/O CMOS I/O ports. Each port has an I/O select direction
register, allowing each pin in the port to be directed for input
or output individually.
Any port set to input can be set to use a pull-up resistor or not
by a program.
P2_0 to P2_7 also function as LED drive ports.
Input port P4_2, P4_6, P4_7 I Input-only ports