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HARDWARE
7531 Group User’s Manual
1-8
PIN DESCRIPTION
Table 1 Pin description
Function
Apply voltage of 2.2–5.5 V to Vcc, and 0 V to Vss.
Reference voltage input pin for A-D converter
Chip operating mode control pin, which is always connected to Vss.
Reset input pin for active “L”
Input and output pins for main clock generating circuit
Connect a ceramic resonator or quartz crystal oscillator between the XIN and XOUT pins.
For using RC oscillator, short between the XIN and XOUT pins, and connect the capacitor and resistor.
If an external clock is used, connect the clock source to the XIN pin and leave the XOUT pin open.
Function expect a port function
Name
Power source (Note 1)
Analog reference
voltage
CNVss
Reset input
Clock input
Pin
Vcc, Vss
VREF
CNVss
RESET
XIN
P00–P07
P10/RxD
P11/TxD
P12/SCLK
P13/SDATA
P14/CNTR0
P20/AN0–
P27/AN7
P30–P35
P36/INT1
P37/INT0
I/O port P0
I/O port P1
I/O port P2 (Note 2)
I/O port P3 (Note 3)
8-bit I/O port.
I/O direction register allows each pin to be individually pro-
grammed as either input or output.
CMOS compatible input level
CMOS 3-state output structure
Whether a built-in pull-up resistor is to be used or not can be
determined by program.
5-bit I/O port
I/O direction register allows each pin to be individually pro-
grammed as either input or output.
CMOS compatible input level
CMOS 3-state output structure
CMOS/TTL level can be switched for P10, P12 and P13
8-bit I/O port having almost the same function as P0
CMOS compatible input level
CMOS 3-state output structure
8-bit I/O port
I/O direction register allows each pin to be individually programmed as either input or output.
CMOS compatible input level (CMOS/TTL level can be switched for P36 and P37).
CMOS 3-state output structure
P30 to P36 can output a large current for driving LED.
Key-input (key-on wake up
interrupt input) pins
Serial I/O1 function pin
Serial I/O2 function pin
Timer X function pin
Input pins for A-D converter
Interrupt input pins
Whether a built-in pull-up resistor is to be used or not can be
determined by program.
XOUT
Clock output
PIN DESCRIPTION
Notes 1: VCC = 2.4 to 5.5 V for the extended operating temperature version (–40 to 85
°C) and the extended operating temperature 125 °C
version (–40 to 125
°C).
2: 6-bit I/O port (P20–P25) for the 32-pin version.
3: 6-bit I/O port (P30–P34, P37/INT0) for the 32-pin version.