Data Sheet

NUC123
May 3, 2017 Page 60 of 99 Rev.2.04
NUC123 SERIES DATASHEET
PS/2 Device Controller (PS2D) 6.12
6.12.1 Overview
PS/2 device controller provides basic timing control for PS/2 communication. All communication
between the device and the host is managed through the CLK and DATA pins. Unlike PS/2
keyboard or mouse device controller, the received/transmit code needs to be translated as
meaningful code by firmware. The device controller generates the CLK signal after receiving a
request to send, but host has ultimate control over communication. DATA sent from the host to
the device is read on the rising edge and DATA sent from device to the host is change after rising
edge. A 16 bytes FIFO is used to reduce CPU intervention. Software can select 1 to 16 bytes for
a continuous transmission.
6.12.2 Features
 Host communication inhibit and request to send detection
 Reception frame error detection
 Programmable 1 to 16 bytes transmit buffer to reduce CPU intervention
 Double buffer for data reception
 S/W override bus