Intel 87C196CB Manual De Usuario
5-2
87C196CB SUPPLEMENT
EP_DIR
Address:
Reset State:
1FE3H
FFH
In I/O mode, each bit of the extended port I/O direction (EP_DIR) register controls the direction of the
corresponding pin. Clearing a bit configures a pin as a complementary output; setting a bit configures
a pin as either an input or an open-drain output. (Open-drain outputs require external pull-ups).
corresponding pin. Clearing a bit configures a pin as a complementary output; setting a bit configures
a pin as either an input or an open-drain output. (Open-drain outputs require external pull-ups).
Any pin that is configured for its extended-address function is forced to the complementary output
mode except during reset, hold, idle, and powerdown.
mode except during reset, hold, idle, and powerdown.
7
0
PIN7
PIN6
PIN5
PIN4
PIN3
PIN2
PIN1
PIN0
Bit
Number
Bit
Mnemonic
Function
7:0
PIN7:0
Extended Address Port Pin
x
Direction
This bit configures EPORT.
x
as a complementary output or an
input/open-drain output.
0 = complementary output
1 = input or an open-drain output
1 = input or an open-drain output
Figure 5-2. Extended Port I/O Direction (EP_DIR) Register
EP_MODE
Address:
Reset State:
1FE1H
FFH
Each bit of the extended port mode (EP_MODE) register controls whether the corresponding pin
functions as a standard I/O port pin or as an extended-address signal. Setting a bit configures a pin as
an extended-address signal; clearing a bit configures a pin as a standard I/O port pin.
functions as a standard I/O port pin or as an extended-address signal. Setting a bit configures a pin as
an extended-address signal; clearing a bit configures a pin as a standard I/O port pin.
7
0
PIN7
PIN6
PIN5
PIN4
PIN3
PIN2
PIN1
PIN0
Bit
Number
Bit
Mnemonic
Function
7:0
PIN7:0
Extended Address Port Pin
x
Mode
This bit determines the mode of EPORT.
x
:
0 = standard I/O port pin
1 = extended-address signal
1 = extended-address signal
Figure 5-3. Extended Port Mode (EP_MODE) Register