CN102779078A - Method for improving cable compatibility of rear panel - Google Patents

Abstract

The invention provides a method for improving cable compatibility of a rear panel. The method includes reducing sideband signal cross talk by increasing descending time of clock signals to achieve the effect that the rear panel is compatible with various Minisas cables and increase the descending time of the clock signals. The method includes the specific steps: 1) improving resistance of a clock signal pull-up resistor and increasing the descending time of the clock signals to reduce signal cross talk by increasing the resistance of the pull-up resistor of the clock signals; and 2) increasing a grounded capacitor at the clock signal end. The descending time of the clock signals can be effectively increased by increasing capacitance, but the descending time cannot be larger than 20ns.

Description

A kind of compatible method of backboard cable that improves

Technical field

The present invention relates to computer communication field, specifically is to utilize to increase the clock signal method of fall time, solves the hard disk backboard problem compatible to the Minisas cable., specifically a kind of compatible method of backboard cable that improves.

Background technology

The SAS hard disk backboard is widely used in taking in the server product effect of " increment cable ", to server machine performance and stable important influence.Along with the continuous variation of client's application demand, the variation that server master board also becomes to the Minisas cable between the hard disk backboard.

Comprised the four edges band signal in the Minisas line, the status indicator lamp of hard disk backboard has been controlled through sideband signals.Sideband signals is deferred to the SFF-8485 agreement, ≤20ns fall time of clock signal.Through to clock signal actual measurement on the backboard; The signal negative edge is usually about 2ns; Because it is too fast that clock signal changes; For the poor slightly Minisas line of sideband lines shielding, can on adjacent sideband lines, cause certain crosstalking, thereby make the status indicator lamp misoperation on the hard disk backboard.

To above problem; Through analysing in depth, we have summed up a kind of mould and have improved the compatible method of backboard cable: thus reach and make the compatibility of backboard through reducing crosstalking between sideband signals the fall time that increases clock signal multiple Minisas cable.

Summary of the invention

The purpose of this invention is to provide a kind of compatible method of backboard cable that improves.

The objective of the invention is to realize that through reducing crosstalking between sideband signals the fall time that increases clock signal, make the compatibility of backboard to multiple Minisas cable thereby reach, concrete grammar fall time that increases clock signal is following by following mode:

1) resistance of increase clock signal pull-up resistor; Thereby through reducing crosstalking between signal the fall time that the pull-up resistor resistance that increases clock signal can increase clock signal;

2) increase a electric capacity at clock signal terminal to ground; Can effectively increase the fall time of clock signal through increasing electric capacity, but it should be noted that fall time can not be greater than 20ns.

The invention has the beneficial effects as follows:, our backboard can be provided cost savings the Minisas cable compatibility of plurality of specifications and manufacturer through top improvement to backboard.

Description of drawings

Fig. 1 is the electrical block diagram that increases the pull-up resistor resistance;

Fig. 2 is the electrical block diagram that is increased to earth capacitance.

Embodiment

Explanation at length below with reference to Figure of description method of the present invention being done.

Increase the fall time of clock signal through the mode that increases resistance and increase electric capacity; Reach and make the compatibility of backboard to multiple Minisas cable thereby reduce crosstalking between sideband signals, concrete grammar fall time that increases clock signal can be divided into following two:

A) resistance of increase clock signal pull-up resistor R1 is as shown in Figure 1;

B) increase a capacitor C 1 at clock signal terminal to ground, as shown in Figure 2;

Carry out more detailed elaboration in the face of content of the present invention down:

First method, thereby through reducing crosstalking between signal the fall time that the pull-up resistor resistance that increases clock signal can increase clock signal;

Second method increases the electric capacity of clock signal to ground, needs to revise earlier the schematic diagram and the PCB of back plate design.Can effectively increase the fall time of clock signal through increasing electric capacity, but it should be noted that fall time can not be greater than 20ns.

Except that the described technical characterictic of instructions, be the known technology of those skilled in the art.

Claims (1)

1. one kind is improved the compatible method of backboard cable; It is characterized in that; Reduce crosstalking between sideband signals the fall time through increasing clock signal, makes the compatibility of backboard to multiple Minisas cable thereby reach, and concrete grammar fall time that increases clock signal is following:

1) resistance of increase clock signal pull-up resistor; Thereby through reducing crosstalking between signal the fall time that the pull-up resistor resistance that increases clock signal can increase clock signal;

2) increase a electric capacity at clock signal terminal to ground; Can effectively increase the fall time of clock signal through increasing electric capacity, but it should be noted that fall time can not be greater than 20ns.

Images