Intel 80C196NU Manuale Utente
C-31
REGISTERS
Px_MODE
P
x
_MODE
x
= 1–4
Address:
Reset State:
Table C-11
Each bit of the port
x
mode (P
x
_MODE) register controls whether the corresponding pin functions as a
standard I/O port pin or as a special-function signal.
7
0
x
= 1–3
PIN7
PIN6
PIN5
PIN4
PIN3
PIN2
PIN1
PIN0
7
0
x
= 4
—
—
—
—
PIN3
PIN2
PIN1
PIN0
Bit
Number
Bit
Mnemonic
Function
7:0
PIN7:0
Port
x
Pin
y
Mode
This bit determines the mode of the corresponding port pin:
0 = standard I/O port pin
1 = special-function signal
1 = special-function signal
Table C-12 lists the special-function signals for each pin.
Table C-11. P
x_MODE Addresses and Reset Values
Register
Address
Reset Value
P1_MODE
1FD0H
00H
P2_MODE
1FD1H
80H
P3_MODE
1FD8H
01H
P4_MODE
1FD9H
00H
Table C-12. Special-function Signals for Ports 1–4
Port 1
Port 2
Port 3
Port 4
Pin
Special-
function
Signal
Pin
Special-
function
Signal
Pin
Special-
function
Signal
Pin
Special-
function
Signal
P1.0
EPA0
P2.0
TXD
P3.0
CS0#
P4.0
PWM0
P1.1
EPA1
P2.1
RXD
P3.1
CS1#
P4.1
PWM1
P1.2
EPA2
P2.2
EXTINT0
P3.2
CS2#
P4.2
PWM2
P1.3
EPA3
P2.3
BREQ#
P3.3
CS3#
P4.3
—
P1.4
T1CLK
P2.4
EXTINT1
P3.4
CS4#
P1.5
T1DIR
P2.5
HOLD#
P3.5
CS5#
P1.6
T2CLK
P2.6
HLDA#
P3.6
EXTINT2
P1.7
T2DIR
P2.7
CLKOUT
P3.7
EXTINT3