Browse Prior Art Database

Control of a State Machine

IP.com Disclosure Number: IPCOM000104717D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Knauft, RG: AUTHOR [+3]

Abstract

The internal control of a clock chip is realized as a state machine. There are two kinds of states:

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Control of a State Machine

      The internal control of a clock chip is realized as a state
machine.  There are two kinds of states:

      Transient states and static states.  The transient states are
changed automatically whereas the static states may only be changed
by interaction of a service processor which is coupled to the clock
chip.

      According to the prior art the service processor diagnoses the
clock chip.  Therefore the service processor issues commands to the
clock chip in order to induce a change from one static state to
another.  This implies that the clock chip takes several intermediate
transient states there upon.  If one of these intermediate transient
states is incorrect, the service processor generally is not capable
to perform a proper diagnoses.

      This problem is helped by modifying the above described prior
art approach:

1.  Every state of the state machine may be defined to be a static
    state by an additional control-bit.

2.  The service processor may put the state machine in any static
    state by an additional command.  Preceding transient states are
    not passed through.

      These two measures give virtually unlimited control of the
state machine so that any incorrect state may be checked and
corrected by means of the service processor.