Figure 162. logic diagram of a bi-directional por – Intel 386 User Manual

Page 482

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16-3

INPUT/OUTPUT PORTS

Figure 16-2. Logic Diagram of a Bi-directional Port

0

1

S

Q

D

Q#

CK

P

n

LTC

From Internal
Peripheral

Read Port
Data latch

Write Port
Data Latch

Read Port
Pin State

To Internal
Peripheral

Write Port
Direction

Read Port
Direction

Write Port
Control

Read Port
Control

Internal Data
Bus (F-Bus)

SYNC

Pin

A3266-01

Q

D

Q#

CK

P

n

DIR

P

n

PIN

V

CC

or

VSS

0

1

S

0

1

S

Q

D

Q#

CK

P

n

CFG

From Internal
Peripheral
Direction
Control

Depends on peripheral's inactive state

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