2

µPD4702

BLOCK DIAGRAM

Reset

A

B

Phase

Discrimination

Edge Detection

8-Bit Up/Down Counter

8-Bit Latch

3-State Output

Carry

Borrow

STB

OE

PIN FUNCTIONS

Function

Incremental signal A phase and B phase signal input pins (Schmitt input)

Count data output pins. Activated when OE is “L”, high impedance outputs when OE

is “H”.

8-bit counter carry signal output pin (active-low)

8-bit counter borrow signal output pin (active-low)

8-bit counter reset signal output pin

Counter is reset when this pin is “H”.

Count data output control signal input pin

Counter data output latch signal. Data is latched on the fall of STB, and is held while

STB = “L”.

Power supply input pin

Ground pin

Pin Name

Input/Output

A, B

Input

(Schmitt)

Output

(3-state)

Carry

Output

Borrow

Output

RESET

Input

(Schmitt)

OE

Input

STB

Input

GND