NCT6627UD Nuvoton Technology Corporation of America, NCT6627UD Datasheet - Page 146

• Manufacturer Part Number: NCT6627UD
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of NCT6627UD

• Lead Free Status / Rohs Status: Supplier Unconfirmed

12. KEYBOARD CONTROLLER
The W83627UHG KBC (8042 with licensed KB BIOS) circuit is designed to provide the functions needed to
interface a CPU with a keyboard and/or a PS/2 mouse and can be used with IBM
computers or PS/2-based systems. The controller receives serial data from the keyboard or PS/2 mouse, checks
the parity of the data, and presents the data to the system as a byte of data in its output buffer. Then, the
controller asserts an interrupt to the system when data are placed in its output buffer. The keyboard and PS/2
mouse are required to acknowledge all data transmissions. No transmission should be sent to the keyboard or
PS/2 mouse until an acknowledgement is received for the previous data byte.
12.1 Output Buffer
The output buffer is an 8-bit, read-only register at I/O address 60H (Default, PnP programmable I/O address LD5-
CR60 and LD5-CR61). The keyboard controller uses the output buffer to send the scan code (from the keyboard)
and required command bytes to the system. The output buffer can only be read when the output buffer full bit in
the register (in the status register) is logical 1.
12.2 Input Buffer
The input buffer is an 8-bit, write-only register at I/O address 60h or 64h (Default, PnP programmable I/O address
LD5-CR60, LD5-CR61, LD5-CR62, and LD5-CR63). Writing to address 60h sets a flag to indicate a data write;
writing to address 64h sets a flag to indicate a command write. Data written to I/O address 60h is sent to the
keyboard (unless the keyboard controller is expecting a data byte) through the controller’s input buffer only if the
input buffer full bit (in the status register) is logical 0.
Multiplex I/O PINS
GP I/O PINS
KINH
Figure 12-1 Keyboard and Mouse Interface
P17
P12~P16
8042
-137-
P25
P21
T0
W83627UHG/NCT6627UD
P24
P20
P27
P10
P26
P23
T1
P22
P11
Publication Release Date: October 26, 2010
MCLK
MDAT
KIRQ
MIRQ
KDAT
KCLK
GATEA20
KBRST
®
-
compatible personal
Revision 1.7