Browse Prior Art Database

Method for forced-odd mode, coupled strobe for source synchronous busses

IP.com Disclosure Number: IPCOM000010110D
Publication Date: 2002-Oct-23
Document File: 3 page(s) / 78K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for forced-odd mode, coupled strobe for source synchronous busses. Benefits include improved performance.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Method for forced-odd mode, coupled strobe for source synchronous busses

Disclosed is a method for forced-odd mode, coupled strobe for source synchronous busses. Benefits include improved performance.

Background

        � � � � � Conventional signaling for a front-side bus (FSB) has two strobes (STROBE_P and STROBE_N) that are 180° out of phase (see Figure 1). The data signals are clocked in by the falling edge of the strobe. The initial condition of the two strobes is a high voltage level.

General description

        � � � � � The disclosed method synchronizes two strobes in odd mode for all strobe transitions. The strobes are generally routed together to take advantage of this odd-coupled mode between the two strobes. The disclosed signaling scheme is more stable than conventional methods, due to clocking off the falling edge(s) rather than both the rising and falling edges.

Advantages

        � � � � � The disclosed method provides advantages, including improved performance due to improved timing.

Detailed description

        � � � � � Hold time is the time between the data signals starting a transition after being clocked in by a strobe. With the disclosed method, hold skew removes the 90° out of phase difference between the data and the strobe. The relationship between the hold skew and the flight time of the data and strobe signals can be described as follows: tHOLD_SKEW = tFLIGHT_DATA_MAX – tFLIGHT_STROBE_MIN.�

        � � � � � Signals routed as microstrips that have odd-mode coupling have a faster f...