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Synchronization of State Machines Using Multi-Port Buffers

IP.com Disclosure Number: IPCOM000036665D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Arimilli, RK: AUTHOR [+4]

Abstract

Problem definition: Two state machines are asynchronous to each other and transfer blocks of data between them. The transfer rate between the two state machines is unknown. The data is to be transferred from one state machine to the other asynchronously with minimum latency.

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Synchronization of State Machines Using Multi-Port Buffers

Problem definition: Two state machines are asynchronous to each other and transfer blocks of data between them. The transfer rate between the two state machines is unknown. The data is to be transferred from one state machine to the other asynchronously with minimum latency.

An effective way to synchronize two state machines is to synchronize them with one signal. This is necessary because multiple signals can get synchronized in different clock cycles due to variable delays. Synchronization using one signal is achieved by transferring the data through a buffer (random-access memory (RAM)). When transferring data between two state machines through this RAM, one state machine writes into the RAM and then grants the other state machine read permission from the RAM, which is multi-ported (having separate write and read address ports). The synchronization problem is now restricted to one signal from the first state machine, the read permission indication to the second state machine.

Performance can be maximized by granting the second state machine permission to read before the first machine has completed the write operation into the RAM. This is possible only if the RAM is multi- ported.

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