CN103812566A - Ethernet Small Form Pluggable (SFP) electric module and method for realizing isochronous Ethernet - Google Patents

Abstract

The invention discloses an Ethernet Small Form Pluggable (SFP) electric module and a method for realizing isochronous Ethernet. The module comprises an Ethernet Media Independent Interface (MII) interface, a Physical (PHY) module and a micro-control unit (MCU), wherein a TxDisable signal in the interface and a local clock signal are connected with an RefCLK signal input pin on the PHY module through a first alternative selector; an RcvCLK signal outputted by the PHY module and a low level signal are connected to a Txfault signal pin in the interface through a second alternative selector; the MCU controls the first alternative selector through a reference clock control signal CLKSEL0 and selects an input signal of a TxDisable pin or the local clock signal as a reference clock input signal; and MCU controls the second alternative selector by a restoration clock control signal CLKSEL1 and restores a clock at an output line of the Txfault pin or outputs low level. According to the Ethernet SFP electric module and the method for realizing isochronous Ethernet, by utilizing the two pins which are only relevant with an optical module, the system clock is transferred to the module as a PHY reference clock, a line clock extracted by PHY is transferred to a system as a system phase-locked loop reference source, and thereby realizing the synchronizing processing of the Ethernet SFP electric module.

Description

Ethernet SFP electricity module and realize the method for synchronous ethernet

Technical field

The present invention relates to synchronous ethernet, be specifically related to Ethernet SFP electricity module and realize the method for synchronous ethernet.

Background technology

SFP(SMALL FORM PLUGGABLE) module is as the hot-swappable little package module of one, and its effect is the mutual conversion that realizes light signal and the signal of telecommunication, is widely applied in telecommunications and data communication field.

SFP module is carried out standard by the multilateral agreement (MSA) between an opponent, can only realize the simple conversion mutually of light signal and the signal of telecommunication, does not relate to code conversion.But along with ethernet standard popularizing gradually at field of telecommunications, following on the basis of MSA standard, much module manufacturer starts to release a kind of so-called " Ethernet SFP electricity module ", be built in SFP electricity module printed circuit board circuit by the chip of realizing physical layer function (PHY) of ethernet standard definition, to reduce taking of circuit board space to equipment main system, realize flexible replacing, speed upgrade simultaneously or change the object of transmission medium.PHY(Physical, physical layer) define data transmission and received needed electricity and light signal, line status, clock reference, data encoding and circuit etc. according to ethernet standard (IEEE802.3x), and provide standard interface to data link layer device.MAC(Medium Access Control on system equipment, media access control layer) according to ethernet standard (IEEE802.3x) definition, provide addressing mechanism, Frame structure, data error inspection, transfer control, the function such as data-interface of standard is provided to network layer.Between MAC and PHY by SGMII(Serial Gigabit Media Independent Interface, serial gigabit media independent interface) Ethernet serial differential bus signals communicates.

As shown in Figure 1, printed board circuit mainly realizes the code conversion between SGMII bus and cable signal, realizes circuit as shown in Figure 2 for the structure of this Ethernet SFP electricity module and application scenarios.

In the SFP of Ethernet shown in Fig. 2 electricity module, left side interface signal is MSA standard (INF-8074i) the SFP attachment unit interface signal that industry is known, wherein RD ± and TD ± be the SGMII difference serial bus signal of module and system equipment interface; RX in the interface of right side on socket RJ45 and TX signal are Ethernet cable signal, and the function of Ethernet SFP electricity module has been exactly the code conversion of SGMII bus signals to Ethernet cable signal.PHY chip adopts internal clocking oscillation source (OSC) as its reference work clock (RefCLK) input.Although TD ± signal contains the clock information of system equipment, but PHY is the transition process completing from TD ± signal decoding to socket signal TX recompile, simultaneously also by the signal TD that originally contains system equipment clock information ± be transformed into only containing the cable signal TX of internal clocking oscillation source (OSC) clock information, lost system equipment clock information, this has just run counter to the principle of synchronous ethernet; On other direction, PHY is decoded to the transition process of RD ± signal recompile completing from socket signal RX, also the signal RX that contains line clock information has been transformed into only simultaneously the signal RD containing internal clocking oscillation source (OSC) clock information ±, lost the clock information of cable signal, this has also run counter to the synchronous principle of upstream and downstream device frequency of synchronous ethernet.

In field of telecommunications, a lot of application scenarios all require can reach Frequency Synchronization between interconnective upstream and downstream equipment, and, use when too network mark standard is carried out telecommunication transmission, conventionally also require to realize Frequency Synchronization, the Ethernet that meets such condition is called as synchronous ethernet, it requires cable signal frequency that system equipment sends must be synchronized with the clock of system equipment, simultaneity factor equipment also possesses (selectively) Frequency Synchronization in the ability of cable signal clock information, according to application scenario can realize both one of or all realize.

In sum, existing Ethernet SFP electricity module is owing to adopting internal clocking oscillation source to supply with PHY chip as its reference work clock, and the contained clock information of cable signal also cannot be uploaded to system, causes the transmission of clock information to be cut off.

Summary of the invention

Technical problem to be solved by this invention is the problem that the contained clock information of solution Ethernet SFP electricity module cable signal also cannot be uploaded to system.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is to provide a kind of Ethernet SFP electricity module, comprise Ethernet MII interface, PHY module and MCU, TxDisable signal in described Ethernet MII interface and local clock signal select 1 selector to be connected the RefCLK signal input pin in described PHY module through the 1, and RcvCLK signal and the low level signal of described PHY module PHY module output select 1 selector to be connected to the Txfault signal pins in described Ethernet MII interface through the 22; Described MCU controls and the one 2 selects 1 controller by reference to clock control signal CLKSEL0, selects the input signal of TxDisable pin or selects local clock signal as with reference to clock input signal; Recovered clock control signal CLKSEL1 controls the 22 and selects 1 controller, is chosen in TxFault pin outlet line recovered clock, or output low level.

In above-mentioned Ethernet SFP electricity module, the connection lossing signal of described PHY module outputs to the LOS pin in described Ethernet MII interface through described MCU, and according to described connection lossing signal, described MCU controls described PHY module hardware and resets and reinitialize.

In above-mentioned Ethernet SFP electricity module, the MOD-DEF1 in described Ethernet MII interface and MOD-DEF2 pin transmit serial communication I2C interface signal.

In above-mentioned Ethernet SFP electricity module, determine the type of current SFP module according to the bus address of I2C interface signal, register address and joint categories, when the bus address of I2C interface signal is A0h, register address while being 2, joint categories while being 00, current SFP module is Ethernet SFP electricity module; When the bus address of I2C interface signal is A0h, register address while being 2, joint categories while being 07, current SFP module is traditional SFP optical module.

In above-mentioned Ethernet SFP electricity module, the bus address A2h by I2C interface signal and register address 250 arrange described PHY module hardware and reset, and write 00 triggering hardware reset, have resetted automatically to revert to 01 afterwards.

In above-mentioned Ethernet SFP electricity module, the bus address A2h by I2C interface signal and register address 250 arrange the initialization of described PHY module, write 00 trigger module initialization, have resetted automatically to revert to 01 afterwards.

The present invention also provides a kind of method of utilizing above-mentioned Ethernet SFP electricity module to realize synchronous ethernet, comprises the following steps:

Utilize MCU output reference clock control signal CLKSEL0 to control the 1 and select 1 controller, select the input signal of TxDisable pin or select local clock signal as with reference to clock input signal;

Utilize MCU output recovered clock control signal CLKSEL1 to control the 22 and select 1 controller, be chosen in TxFault pin outlet line recovered clock, or output low level.

In said method, Ethernet SFP electricity module module powers on default setting for using local clock signal, recovered clock output low level.

The present invention, in the SFP of existing MSA standard attachment unit interface signal, utilize only two pins relevant to optical module, transmission system clock to module as PHY reference clock, transmit PHY extract line clock to system as system phase-locked loop reference source, the synchronization process that has realized Ethernet SFP electricity module, is used this generic module not support the shortcoming of synchronous ethernet before solving, and keeps compatibility and the stability of module simultaneously.

Accompanying drawing explanation

Fig. 1 is existing Ethernet SFP electricity module structure and application scenarios schematic diagram;

Fig. 2 is that existing Ethernet SFP electricity module realizes circuit diagram;

Fig. 3 is that Ethernet SFP electricity module provided by the invention realizes circuit diagram.

Embodiment

Realize synchronous ethernet, Ethernet SFP electricity module need to take two pins of MSA standard SFP optical module, for system reference clock being provided and extracting line-recovered clock; Meanwhile, the LINKDOWN(of PHY module connect lose) signal demand can be with the formal output of hardware pin signal, thereby the SFP optical module of compatibility standard MSA; In addition, also to consider that compatible great majority are in the legacy system of network operation, make it in the time of the Ethernet SFP electricity module using after synchronization process, do not need to change circuit board, only need upgrade software (comprising FPGA (Field Programmable Gate Array)) just can realize the support to synchronous ethernet.

For this reason, the invention provides a kind of Ethernet SFP electricity module, utilize two pin TxDisable of MSA standard definition and Txfault to realize the transmission of the clock information on the both direction that synchronous ethernet requires, make system equipment in the time using Ethernet SFP electricity module, be unlikely to the interruption that causes clock information to transmit.

Below in conjunction with accompanying drawing, the present invention is described in detail.

As shown in Figure 3, Ethernet SFP electricity module provided by the invention comprises Ethernet MII interface and PHY module, and the LOS pin of above-mentioned TxDisable and Txfault pin and output LINKDOWN signal is arranged on Ethernet MII interface.

Same as the prior art, PHY module connects RJ45 interface by transformer, to realize and being connected of Ethernet, data transmit-receive signal TD+, TD-, RD+ and RD-in Ethernet MII interface are correspondingly connected to respectively in PHY module, to realize data-transformation facility.

Ethernet SFP electricity module is provided with micro-control unit (MCU), the local clock signal of the TxDisable signal in Ethernet MII interface and local crystal oscillator clock oscillation source (OSC) output selects 1 selector to be connected to the RefCLK signal input pin in PHY module through the 1, and RcvCLK signal and the low level signal of the output of PHY module select 1 selector to be connected to the Txfault signal pins in Ethernet MII interface through the 22.

The PHY reference clock control signal CLKSEL0 of MCU output controls the 1 and selects 1 controller, selects using the input signal of TxDisable pin as with reference to clock input signal, or selects local clock signal as with reference to clock input signal.The recovered clock control signal CLKSEL1 of MCU output controls the 22 and selects 1 controller, is chosen in TxFault pin outlet line recovered clock, or output low level.

MOD-DEF1 in Ethernet MII interface and MOD-DEF2 are the serial communication I2C interface signal of MSA standard (INF-8074i) definition, realize following functions by I2C interface signal:

(1) identification module type is SFP optical module or SFP electricity module, compatible SFF-8472 standard definition;

(2) see through single-chip microprocessor MCU choice for use local signal or external timing signal as the reference clock of PHY module, also can control circuit recovered clock whether export.Module powers on default setting for using local clock signal, and recovered clock output low level does not need the legacy system of synchronous ethernet and the legacy system of system reference clock cannot be provided with compatibility;

(3) seeing through single-chip microprocessor MCU realizes the hardware reset of PHY module and reinitializes.In the time that reference clock is supplied with by module-external, clock behavior is unpredictable, and abnormal clock guild makes the disorder of PHY functions of modules, now needs PHY module to carry out hardware reset and initialization intervention, to improve the stability of module;

It in table 1, is the description of the major function difference pin of Ethernet SFP electricity module and traditional SFP optical module in the present invention.

Table 1:

Select above 3 signals can meet to greatest extent system compatibility, because for most systems, when circuit design, these 3 pins have all been introduced programmable logic device by the SFP optical module of MSA standard, so just can in FPGA (Field Programmable Gate Array), process flexibly for SFP optical module and SFP electricity module.

Table 2 has provided the definition of supporting the SFP electricity module of synchronous ethernet to be different from the I2C register of the SFP optical module of MSA standard.

Table 2:

In the present invention, two pins of the TxDisable of utilization and Txfault have following characteristics:

(1) the old system equipment circuit of the overwhelming majority designing according to MSA standard SFP optical module reference circuit, because industry has generally been introduced programmable logic device by them, programmable logic device inside also possesses device systems clock conventionally, old system is just easy to upgrading to support synchronous ethernet, has guaranteed that the present invention has best new-old system equipment compatibility;

(2) these two pins itself only have application value in the time of MSA standard SFP optical module, for accounting for most Ethernet SFP electricity modules, number of applications there is no corresponding meaning, just can utilize them to transmit clock information, guarantee that the present invention has good module compatibility.

On this basis, the present invention also provides a kind of and has utilized above-mentioned Ethernet SFP electricity module to realize the method for synchronous ethernet, comprises the following steps:

Utilize MCU output reference clock control signal CLKSEL0 to control the 1 and select 1 controller, select the input signal of TxDisable pin or select local clock signal as with reference to clock input signal;

Utilize MCU output recovered clock control signal CLKSEL1 to control the 22 and select 1 controller, be chosen in TxFault pin outlet line recovered clock, or output low level.

The present invention is not limited to above-mentioned preferred forms, and anyone should learn the structural change of making under enlightenment of the present invention, and every have identical or close technical scheme with the present invention, within all falling into protection scope of the present invention.

Claims (8)

1. Ethernet SFP electricity module, comprises Ethernet MII interface and PHY module, it is characterized in that, also comprises MCU,

TxDisable signal in described Ethernet MII interface and local clock signal select 1 selector to be connected the RefCLK signal input pin in described PHY module through the 1, and RcvCLK signal and the low level signal of described PHY module PHY module output select 1 selector to be connected to the Txfault signal pins in described Ethernet MII interface through the 22;

Described MCU controls and the one 2 selects 1 controller by reference to clock control signal CLKSEL0, selects the input signal of TxDisable pin or selects local clock signal as with reference to clock input signal; Recovered clock control signal CLKSEL1 controls the 22 and selects 1 controller, is chosen in TxFault pin outlet line recovered clock, or output low level.

2. Ethernet SFP electricity module as claimed in claim 1, it is characterized in that, the connection lossing signal of described PHY module outputs to the LOS pin in described Ethernet MII interface through described MCU, according to described connection lossing signal, described MCU controls described PHY module hardware and resets and reinitialize.

3. Ethernet SFP electricity module as claimed in claim 1, is characterized in that, the MOD-DEF1 in described Ethernet MII interface and MOD-DEF2 pin transmit serial communication I2C interface signal.

4. Ethernet SFP electricity module as claimed in claim 3, it is characterized in that, determine the type of current SFP module according to the bus address of I2C interface signal, register address and joint categories, when the bus address of I2C interface signal is A0h, register address while being 2, joint categories while being 00, current SFP module is Ethernet SFP electricity module; When the bus address of I2C interface signal is A0h, register address while being 2, joint categories while being 07, current SFP module is traditional SFP optical module.

5. Ethernet SFP as claimed in claim 3 electricity module, is characterized in that, the bus address A2h by I2C interface signal and register address 250 arrange described PHY module hardware and reset, and write 00 triggering hardware reset, has resetted automatically to revert to 01 afterwards.

6. Ethernet SFP as claimed in claim 3 electricity module, is characterized in that, the bus address A2h by I2C interface signal and register address 250 arrange the initialization of described PHY module, write 00 trigger module initialization, has resetted automatically to revert to 01 afterwards.

7. the Ethernet SFP electricity module of utilization as described in claim 1-6 any one realizes the method for synchronous ethernet, it is characterized in that, comprises the following steps:

Utilize MCU output reference clock control signal CLKSEL0 to control the 1 and select 1 controller, select the input signal of TxDisable pin or select local clock signal as with reference to clock input signal;

Utilize MCU output recovered clock control signal CLKSEL1 to control the 22 and select 1 controller, be chosen in TxFault pin outlet line recovered clock, or output low level.

8. method as claimed in claim 8, is characterized in that, Ethernet SFP electricity module module powers on default setting for using local clock signal, recovered clock output low level.

Images