Logic Diagram Of A Bi-Directional Port - Intel 386 User Manual

From Internal
Peripheral
Read Port
Data latch
Write Port
Data Latch
Read Port
Pin State
To Internal
Peripheral
Internal Data
Bus (F-Bus)
Write Port
Direction
Read Port
Direction
From Internal
Peripheral
Direction
Control
Write Port
Control
Read Port
Control
Figure 16-2. Logic Diagram of a Bi-directional Port
P n LTC
Q
D
Q#
CK
P n PIN
P n DIR
Q
D
Q#
CK
P n CFG
Q
D
Q#
CK
INPUT/OUTPUT PORTS
0
1
S
SYNC
0
1
S
0
1
S
† Depends on peripheral's inactive state
Pin
V
CC
or
V SS†
A3266-01
16-3