7477 datasheet(21/361 Pages) RENESAS

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HARDWARE

1.5 Pin description

7470/7471/7477/7478 GROUP USER’S MANUAL

1-14

Name

Power source

Analog power source

Reference voltage input

Reset input

Clock input

Clock output

I/O port P0

Functions

• Apply the following voltage to the VCC pin:

2.7 V to 4.5 V

(at f(XIN) = (2.2 VCC–2) MHz clock input oscillation frequency)

4.5 V to 5.5 V

(at f(XIN) = 8 MHz clock input oscillation frequency).

• Apply 0 V to the VSS pin.

• Ground level input pin for the A-D converter.

• Apply the same voltage as VSS pin to the AVSS pin.

Note: This pin is dedicated to 56P6N-A package

products among the 7471/7478 group.

• Reference voltage input pin for the A-D converter.

• When using the A-D converter, apply 0.5 VCC (Q

2) to VCC [V].

• When not using the A-D converter, connect to VCC.

• Reset input pin

• The microcomputer is put into a reset state by

keeping the RESET pin at “L” for 2

µs or more,

and the reset state is released by returning the

RESET

pin to “H.”

• An input pin and an output pin for the main clock

generating circuit.

• Connect a ceramic resonator or a quartz-crystal

oscillator between pins XIN and XOUT.

• A feedback resistor is incorporated between the

XIN and the XOUT pins.

• To use an external clock input, connect the clock

oscillation source to the XIN pin and leave the

XOUT pin open.

• Port P0 is an 8-bit I/O port.

• The output structure is CMOS output.

• In input mode, a pull-up transistor is connectable

in units of one bit.

• In input mode, a key-on wake up function is pro-

vided.

1.5 Pin description

Tables 1.5.1 to 1.5.3 show a pin description.

For pin functions in the EPROM mode of the built-in programmable ROM version, refer to “1.19.2 Pin

description.”

Table 1.5.1 Pin description (1)

Input/

Output

Input

Output

I/O

VCC, VSS

AVSS

VREF

RESET

XIN

XOUT

P00–P07

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