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Byte Decode for Determining Setup Mode

IP.com Disclosure Number: IPCOM000104253D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 24K

Publishing Venue

IBM

Related People

Agoglia, RJ: AUTHOR [+5]

Abstract

Disclosed is a method for determining whether a circuit is in a setup mode or in the normal operating mode. The values stored in all of the bit registers of a port are provided as inputs to a decoding circuit which thereby decodes the entire byte stored in the registers.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Byte Decode for Determining Setup Mode

      Disclosed is a method for determining whether a circuit is in a
setup mode or in the normal operating mode.  The values stored in all
of the bit registers of a port are provided as inputs to a decoding
circuit which thereby decodes the entire byte stored in the
registers.

      In a preferred version of this method, an I/O controller
circuit is placed in setup mode when Bit 6 of Port 94H is at a zero
level.  The other bits of Port 94H are used to determine which other
circuits are in a setup mode.  However, the outputs of the other bit
registers of Port 94H are also used in the decode circuit associated
with the I/O control- ler, assuring that they each are at a one level
whenever the I/O controller circuit is placed in the setup mode.  The
decode circuit is formed with conventional logic gates.  This method
assures that the I/O controller circuit is not placed in the setup
mode inadvertently by code which places one of the other circuits in
setup mode without setting all other bits, including Bit 6, to a one
level.

Disclosed Anonymously.