Intel 8XC196NT 87C196CB SUPPLEMENT, 2. Extended Port I/O Direction EPDIR Register, Epdir, Epmode

Models: 8XC196NT 87C196CB

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EP_DIR

87C196CB SUPPLEMENT

EP_DIR

Address:

1FE3H

 

Reset State:

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).

Any pin that is configured for its extended-address function is forced to the complementary output mode except during reset, hold, idle, and powerdown.

7

PIN7

PIN6

PIN5

PIN4

 

 

 

 

0

PIN3

PIN2

PIN1

PIN0

 

 

 

 

Bit

Bit

 

Function

Number

Mnemonic

 

 

 

 

 

 

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

 

 

 

 

Figure 5-2. Extended Port I/O Direction (EP_DIR) Register

EP_MODE

Address:

1FE1H

 

Reset State:

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.

7

0

PIN7

PIN6

PIN5

PIN4 PIN3

PIN2

PIN1

PIN0

Bit

Bit

 

Function

Number

Mnemonic

 

 

 

 

 

 

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

 

 

 

 

Figure 5-3. Extended Port Mode (EP_MODE) Register

5-2

Page 51
Image 51
Intel 8XC196NT 87C196CB SUPPLEMENT, 2. Extended Port I/O Direction EPDIR Register, 3. Extended Port Mode EPMODE Register