INPUT/OUTPUT PORTS

.

Ω

ON

 

.

Ω

OFF

 

R=500.

 

R=500.

 

VCC

 

 

P1

 

VCC

 

 

P1

 

.

 

 

 

.

 

 

 

Ω

ON

IOH

Ω

ON

IOH

R=10k.

R=10k.

.

 

 

P2

 

.

 

 

P2

 

 

Ω

ON

 

 

Ω

ON

 

R=100k.

 

R=100k.

 

 

 

 

P3

 

 

 

 

P3

 

INTERNAL

 

 

 

 

INTERNAL

 

 

 

 

BUS

 

 

 

 

BUS

 

 

 

 

READ

 

 

OFF

N

READ

 

 

OFF

N

 

 

 

 

 

 

(A) When accelerator circuit is activated

(B) When "1" data is held

 

.

Ω

OFF

 

 

 

 

 

 

R=500.

 

 

 

 

 

 

VCC

 

 

P1

 

 

 

 

 

 

.

 

 

 

 

 

 

 

 

Ω

OFF

 

 

 

 

 

 

R=10k.

 

 

 

 

 

 

.

 

 

P2

 

 

 

 

 

 

 

Ω

OFF

 

 

 

 

 

 

R=100k.

 

 

 

 

 

 

 

 

 

P3

 

 

 

 

 

 

INTERNAL

 

 

 

 

 

 

 

 

 

BUS

 

 

 

 

 

 

 

 

 

READ

 

 

ON

IOL

 

 

 

 

 

 

 

 

N

 

 

 

 

 

(C) When "0" data is held

Figure 5-5 Quasi-bidirectional port equivalent circuit

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Image 204
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