Register-based programmable post-silicon system to patch and dynamically modify the behavior of synchronous state machines
US5949251A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 1, 1997 |
| Grant date | Sep 7, 1999 |
| Priority date | — |
| Expiry date | Aug 1, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/23289
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The present invention allows the behavior of a state machine to be readily modified by software after it has been fabricated in silicon. To perform these modifications, the present invention uses special patch registers, multiplexers, and comparators to bypass certain states within the sequence of states within the combinatorial logic of the state machine and/or add new state sequences. Each patch register stores a state to be patched, a next state, and outputs. The state to be patched is the state that will be modified, while the next state is the state the state machine transitions into from the state to be patched, and the outputs are the outputs generated and asserted by the state machine while within the next state. Many such patch registers can be used by the present invention to define many modifications. Using this patch mechanism, the present invention allows new states to be added and existing states to be removed from the sequence of states that the state machine cycles through. To implement the functionality of the patch registers within the present invention, a separate comparator is connected to each patch register to determine when the present state of the state mach…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.