Programmable Connector Selector for the Keyboard and Mouse Ports
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Bealkowski, R: AUTHOR [+3]
This article describes a technique which utilizes defined selector bit to allow a personal computer (PC) to recognize the keyboard device regardless of the to which the device is attached.
Programmable Connector Selector for the Keyboard and
describes a technique which utilizes defined
selector bit to allow a personal computer (PC) to recognize the
keyboard device regardless of the to which the device is attached.
In a PC
system where there are two identical connectors as PORT
A and PORT B on the back of the system one connector is used for
the keyboard device and the can be used for a mouse device. If the
user inserts the keyboard device into the mouse the system will not
operate. Conversely, if the device is inserted into the keyboard
connector, the again will not operate.
technique disclosed herein a bit called the bit has been
defined to allow the system to the keyboard device, regardless of the
connector which the device is attached. With this bit, software
program which of the connectors refers to the keyboard which refers
to the mouse device. Two commands have defined to allow the system
programmer to set and clear selector bit. The user is able to attach
the keyboard mouse devices to either of the externally available The
are defined as follows:
Command BD hex - Set Selector Bit
Command BE hex - Clear Selector Bit
Fig. 1 is a
block diagram showing selector bit logic.
and 3 are block diagrams showing data routing and inbound data
routing, The selector bit is set to one after a reset, specifies
that keyboard data is available on PORT A mouse da...