Browse Prior Art Database

Keyboard Function Key Control

IP.com Disclosure Number: IPCOM000082032D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 55K

Publishing Venue

IBM

Related People

Duggan, CJ: AUTHOR

Abstract

Function toggle switches and push buttons normally included on a computer console are replaced by function keys on a keyboard, which are constantly enabled by mricrocode generated signals even though the keyboard itself may not be enabled.

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Keyboard Function Key Control

Function toggle switches and push buttons normally included on a computer console are replaced by function keys on a keyboard, which are constantly enabled by mricrocode generated signals even though the keyboard itself may not be enabled.

The microcode contained in storage 10, Fig. 1, is accessed by central processing unit (CPU) 20 to provide keyboard enabling signals to keyboard attachment 30. Keyboard 50 is attached to the computer system as an input/output (I/O) device and is selectively enabled and disabled under program control. In this instance, however, the microcode constantly enables certain function keys on the keyboard, while the remainder of the keyboard may be disabled.

Whenever any key on keyboard 50 is operated, a KBD GATE signal is generated and applied to set latch 31, Fig. 2, and thereby cause an interrupt to CPU 20, applied as a load signal for loading data from the keyboard over bus 51 into KBD DATA REG 32 and applied to set DATA GATE latch 33. The interrupt signal causes entry into a microprogram for interrogating the contents of register
32. This is accomplished by issuing a command over data bus out (DBO) 21, and providing proper control signals on control bus 22 to command decode logic 35 in attachment 30.

Logic 35 is responsive to the command and provides a SENSE KBD REG signal to AND circuit 36, whereby it passes the data from register 32 via OR circuit 37 and data bus in (DBI) 23 to CPU 20.

The microcode then determines if the data corresponding to the key depressed represents a key which is constantly enabled. If the key depressed does represent one which is constantly ena...