PC87351 datasheet(21/86 Pages) NSC

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1.0 Signal/Pin Connection and Description (Continued)

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1.4.7

Keyboard and Mouse Controller (KBC)

Signal

Pin/s

I/O

Buffer Type

Description

GA20

I/O

INTS/OD4

Gate A20. KBC gate A20 (P21) output.

KBCLK

100

I/O

INTS/OD4

Keyboard Clock. Transfers the keyboard clock between the SuperI/O chip

and the external keyboard using the PS/2 protocol.

This pin is driven by the internal, inverted KBC P26 signal, and is

connected internally to the T0 signal of the KBC. External pull-up resistor

to 5V is required (for PS/2 compliance). The pin is monitored for wake-up

event detection. However, to enable the activity during power off, it must be

pulled up to Keyboard and Mouse standby voltage.

KBDAT

101

I/O

INTS/OD4

Keyboard Data. Transfers the keyboard data between the SuperI/O chip

and the external keyboard using the PS/2 protocol.

This pin is driven by the internal, inverted KBC P27 signal, and is

connected internally to KBC P10. External pull-up resistor to 5V is required

(for PS/2 compliance). The pin is monitored for wake-up event detection.

To enable the activity, it must be pulled up to Keyboard and Mouse standby

voltage.

KBRST

I/O

INTS/OD4

KBD Reset. Keyboard Reset (P20) output.

MCLK

102

I/O

INTS/OD4

Mouse Clock. Transfers the mouse clock between the SuperI/O chip and

the external keyboard using the PS/2 protocol.

This pin is driven by the internal, inverted KBC P23 signal, and is

connected internally to KBC’s T1. External pull-up resistor to 5V is

required (for PS/2 compliance). The pin is monitored for wake-up event

detection. To enable the activity, it must be pulled up to Keyboard and

Mouse standby voltage.

MDAT

103

I/O

INTS/OD4

Mouse Data. Transfers the mouse data between the SuperI/O chip and

the external keyboard using the PS/2 protocol.

This pin is driven by the internal, inverted KBC P22 signal, and is

connected internally to KBC’s P11. External pull-up resistor to 5V is

required (for PS/2 compliance). The pin is monitored for wake-up event

detection. To enable the activity, it must be pulled up to Keyboard and

Mouse standby voltage.

P12

42, 98,

127

I/O

INTS/OD4

I/O Port. KBC open-drain signal for general-purpose input and output,

controlled by KBC ﬁrmware.

P17

41, 42,

128

I/O

INTS/OD4

I/O Port. KBC open-drain signal for general-purpose input and output,

controlled by KBC ﬁrmware.

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