455A Datasheet, PDF (5/148 Pages) Renesas Technology Corp – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

455A Group
PIN DESCRIPTION
Table 3 Pin description
Pin
VDD
VSS
CNVSS
VDCE
Name
Power source
Power source
CNVSS
Voltage drop detection
circuit enable
XIN
XOUT
XCIN
XCOUT
Main clock input
Main clock output
Sub clock input
Sub clock output
RESET Reset I/O
D0−D5
I/O port D
(Input is examined by
skip decision.)
D6, D7
I/O port D
(Input is examined by
skip decision.)
P00−P03 I/O port P0
P10−P13 I/O port P1
P20−P23 I/O port P2
P30−P33 I/O port P3
C
COM0−
COM3
SEG0−
SEG31
Output port C
Common output
Segment output
CNTR Timer I/O
INT
Interrupt input
VLC3−
VLC1
LCD power source
Input/Output
Function
−
Connected to a plus power supply.
−
Connected to a 0 V power supply.
−
Connect this pin to VSS and always apply “L”(0 V) to it.
Input
This pin is used to operate/stop the voltage drop detection circuit.
When “H“ level is input to this pin, the circuit starts operating.
When “L“ level is input to this pin, the circuit stops operating.
Input
Output
I/O pins of the main clock generating circuit. When using a ceramic resonator,
connect it between pins XIN and XOUT. A feedback resistor is built-in between them.
Input
Output
I/O pins of the sub-clock generating circuit. Connect a 32.768 kHz quartz-crystal
oscillator between pins XCIN and XCOUT. A feedback resistor is built-in between
them. XCIN and XCOUT pins are also used as ports D6 and D7, respectively.
I/O
I/O
I/O
I/O
I/O
I/O
I/O
Output
Output
Output
I/O
Input
−
An N-channel open-drain I/O pin for a system reset. When the SRST instruction,
watchdog timer, the built-in power-on reset or the voltage drop detection circuit
causes the system to be reset, the RESET pin outputs “L” level.
Each pin of port D has an independent 1-bit wide I/O function. The output structure
can be switched to N-channel open-drain or CMOS by software. For input use, set
the latch of the specified bit to “1” and select the N-channel open-drain. Port D0 to
D5 has a key-on wakeup function and a pull-up function. Both functions can be
switched by software.
Port D5 is also used as INT pin.
Each pin of port D has an independent 1-bit wide I/O function. The output structure
is N-channel open-drain. Port D6, D7 has a key-on wakeup function and a pull-up
function. Both functions can be switched by software.
Ports D6 and D7 are also used as XCIN pin and XCOUT pin, respectively.
Port P0 serves as a 4-bit I/O port. The output structure can be switched to N-
channel open-drain or CMOS by software. For input use, set the latch of the
specified bit to “1” and select the N-channel open-drain. Port P0 has a key-on
wakeup function and a pull-up function. Both functions can be switched by software.
Ports P00-P03 are also used as SEG16-SEG19, respectively.
Port P1 serves as a 4-bit I/O port. The output structure can be switched to N-
channel open-drain or CMOS by software. For input use, set the latch of the
specified bit to “1” and select the N-channel open-drain. Port P1 has a key-on
wakeup function and a pull-up function. Both functions can be switched by software.
Ports P10-P13 are also used as SEG20-SEG23, respectively.
Port P2 serves as a 4-bit I/O port. The output structure can be switched to N-
channel open-drain or CMOS by software. For input use, set the latch of the
specified bit to “1” and select the N-channel open-drain. Port P2 has a key-on
wakeup function and a pull-up function. Both functions can be switched by software.
Ports P20–P23 are also used as SEG24–SEG27, respectively.
Port P3 serves as a 4-bit I/O port. The output structure can be switched to N-
channel open-drain or CMOS by software. For input use, set the latch of the
specified bit to “1” and select the N-channel open-drain. Port P3 has a key-on
wakeup function and a pull-up function. Both functions can be switched by software.
Ports P30–P33 are also used as SEG28–SEG31, respectively.
1-bit output port. The output structure is CMOS. Port C is also used as CNTR pin.
LCD common output pins. Pins COM0 and COM1 are used at 1/2 duty, pins COM0–
COM2 are used at 1/3 duty and pins COM0–COM3 are used at 1/4 duty.
LCD segment output pins. SEG0–SEG2 pins are used as VLC3–VLC1 pins,
respectively. SEG16-SEG31 pins are used as Ports P00-P03, Ports P10-P13, Ports
P20-P23, and Ports P30-P33, respectively.
CNTR pin has the function to input the clock for the timer 1 event counter and to
output the PWM signal generated by timer 2. CNTR pin is also used as Port C.
INT pin accepts external interrupts. They have the key-on wakeup function which
can be switched by software. INT pin is also used as Port D5.
These are the LCD power supply pins. If an internal resistor is used, connect the
VLC3 pin to the VDD pin. (If brightness adjustment is required, connect via a resistor.)
When using an external power supply, apply voltage such that VSS ≤ VLC1 ≤ VLC2 ≤
VLC3 ≤ VDD. Pins VLC3 to VLC1 also function as pins SEG0 to SEG2.
Rev.1.01 Feb 15, 2008 Page 5 of 146
REJ03B0224-0101