Intel 386 - Manual (Page 612)

D-47
SYSTEM REGISTER QUICK REFERENCE
D.44 P nDIR
Port DIrection
P
nDIR (n=1–3)
(read/write)
Expanded Addr:
ISA Addr:
Reset State: F864H, F86CH, F874H
—
FFH
7 0
PD7 PD6 PD5 PD4 PD3 PD2 PD1 PD0
Bit
Number
Bit
Mnemonic
Function
7–0 PD7:0 Pin Direction:
0 = Configures the pin as a complementary output.
1 = Configures the pin as an open-drain output or high-impedance input.