CN207264377U

CN207264377U - Programmable I2C multiple selector and interchanger

Info

Publication number: CN207264377U
Application number: CN201721070427.4U
Authority: CN
Inventors: 郑盛村; 毛祖书
Original assignee: Shennan Circuit Co Ltd
Current assignee: Shennan Circuit Co Ltd
Priority date: 2017-08-25
Filing date: 2017-08-25
Publication date: 2018-04-20
Anticipated expiration: 2027-08-25

Abstract

The utility model discloses a kind of programmable I2C multiple selector, including：Complex programmable logic device (CPLD) chip and the processor for being integrated with bus master unit, the CPLD chips are connected with the bus master unit by I2C buses, the I2C buses are made of data cable SDA and clock cable SCL, SCL input terminals are expanded to n SC output terminal by the CPLD chips, so that, n roads SDx/SCx down going channels will be expanded to by SDA/SCL data feedback channels all the way, n is positive integer, x=0,1 ... ... n.Corresponding interchanger is also provided.The utility model will expand to multichannel for example more than eight road down going channels by data feedback channel all the way using CPLD chips, solve the problems, such as that existing PCA9548A can only will expand to eight pairs of down going channels by data feedback channel all the way, design is simplified, reduce product complexity, application flexibility is improved, and cost can be saved.

Description

Programmable I2C multiple selector and interchanger

Technical field

The utility model is related to computer and field of communication technology, and in particular to a kind of programmable I2C multiple selector and Interchanger.

Background technology

I2C（Or it is written as I²C）Bus is that the one kind developed by Philips companies is simple, bidirectional two-line synchronous serial is total Line.It only needs both threads to transmit information between the device being connected in bus.

PCA9548A is a octal system two-way reversing switch by I2C bus marcos.As shown in Figure 1, its each pair SCL/SDA data feedback channels can expand to eight pairs of down going channels, can be programmed into the content of register to it by I2C buses To select any single SCx/SDx passages.

In the design of interchanger, it is desirable to the I2C interface of all optical ports can be had access to, come for 8 mouthfuls of interchangers Say, a PCA9548A can meet, but to 24 mouthfuls, 48 mouthfuls etc of interchanger must will be used more Pca9548, this adds increased product complexity, hence it is evident that adds cost.

Utility model content

The utility model embodiment provides a kind of programmable I2C multiple selector and interchanger, by using CPLD chips To extend I2C buses, solve the problems, such as that PCA9548A can only will expand to eight road down going channels by data feedback channel all the way.

Used technical problem is：

On the one hand, there is provided a kind of programmable I2C multiple selector, including：Complex programmable logic device (CPLD) chip and The processor of bus master unit is integrated with, the CPLD chips are connected with the bus master unit by I2C buses, described I2C buses are made of data cable SDA and clock cable SCL, and SCL input terminals are expanded to n SC and exported by the CPLD chips End, so that, n roads SDx/SCx down going channels will be expanded to by SDA/SCL data feedback channels all the way, n is positive integer, x=0,1 ... ... n.

Wherein, the SDA forms the n roads SDx/SCx down going channels, the n with the n SC output terminal expanded respectively A SC output terminals are respectively as the SC output terminals of the n roads SDx/SCx down going channels, and the SDA is directly as the n roads SDx/ The SD output terminals of SCx down going channels.

When for extending fiber optic network passage, the n roads SDx/SCx down going channels connect n fiber optic network mouth respectively. N can be the positive integer more than 8.

On the other hand, a kind of interchanger, including processor and CPLD chips are also provided, bus is integrated with the processor Main control unit, the CPLD chips are connected with the bus master unit by I2C buses, form as described above programmable I2C multiple selector.

As can be seen from the above technical solutions, the utility model embodiment has the following advantages：

It is connected using CPLD chips with processor, forms programmable I2C multiple selector, can will be all the way on SDA/SCL Row of channels expands to multichannel for example more than eight road SDx/SCx down going channels, and solving existing PCA9548A can only will on the way Row of channels expands to the problem of eight pairs of down going channels, in this way, to 24 mouthfuls, 48 mouthfuls etc of interchanger, it is not necessary to using multiple PCA9548A, it is only necessary to a CPLD chip can be achieved, and use less SDA pins, so that, design has been simplified, has been dropped Low product complexity, improves application flexibility, and can save cost.

Brief description of the drawings

, below will be to embodiment and description of the prior art in order to illustrate more clearly of the utility model embodiment technical solution Needed in attached drawing be briefly described, it should be apparent that, drawings in the following description are only the utility model Some embodiments, for those of ordinary skill in the art, without creative efforts, can also be according to this A little attached drawings obtain other attached drawings.

Fig. 1 is the principle schematic for carrying out I2C bus extensions using PCA9548A in the prior art；

Fig. 2 is a kind of principle schematic for programmable I2C multiple selector that the utility model embodiment provides.

Embodiment

It is real below in conjunction with the utility model in order to make those skilled in the art more fully understand the utility model The attached drawing in example is applied, the technical scheme in the utility model embodiment is clearly and completely described, it is clear that described Embodiment is only the embodiment of the utility model part, instead of all the embodiments.Based on the reality in the utility model Apply example, those of ordinary skill in the art's all other embodiments obtained without making creative work, all should When the scope for belonging to the utility model protection.

Term " first " in the specification and claims of the utility model and above-mentioned attached drawing, " second ", " the 3rd " Etc. being for distinguishing different objects, rather than for describing particular order.In addition, term " comprising " and " having " and they Any deformation, it is intended that cover non-exclusive include.Such as contain the process of series of steps or unit, method, system, The step of product or equipment are not limited to list or unit, but the step of not listing or unit are alternatively further included, Or alternatively further include for the intrinsic other steps of these processes, method, product or equipment or unit.

Below by specific embodiment, it is described in detail respectively.

Please refer to Fig.2, one embodiment of the utility model, there is provided a kind of programmable I2C multiple selector, can be used in and hand over In changing planes.The programmable I2C multiple selector may include：

Complex programmable logic device (CPLD) chip and the processor for being integrated with bus master unit, the CPLD chips and The bus master unit is connected by I2C buses, and the I2C buses are made of data cable SDA and clock cable SCL, institute State CPLD chips and SCL input terminals are expanded into n SC output terminal, so that, n roads will be expanded to by SDA/SCL data feedback channels all the way SDx/SCx down going channels, n are positive integer, x=0,1 ... ... n.

Wherein, CPLD only extends SCL, SDA is not extended, and SDA forms n roads with the n SC output terminal expanded respectively Down going channel；That is, for described n SC output terminals respectively as the SC output terminals of the n roads SDx/SCx down going channels, the SDA is straight Connect the SD output terminals as the n roads SDx/SCx down going channels.

When for extending fiber optic network passage, the n roads SDx/SCx down going channels can connect n fiber optic network respectively Mouthful.When for other application scene, it can also be used to connect other port/equipment.

Optionally, n is the positive integer more than 8.

Wherein, the CPLD chips connect 3.3V power supplys.

Wherein, the bus master unit can be I2CSMBus master.

As above, the utility model realizes the function similar to PCA9548A using pin vacant CPLD, and uses Less pin, so as to reduce the cost.CPLD（Complex Programmable Logic Device, complex programmable logic Device）, it is the device come out from PAL and GAL device developments, in contrast scale is big, complicated, belongs to large-scale integrated electricity Road scope.It is a kind of user according to respective need and the voluntarily digital integrated electronic circuit of constitutive logic function.Its basic design method It is by Integrated Development software platform, the methods of with schematic diagram, hardware description language, corresponding file destination is generated, under Code is transmitted in objective chip by download cable, realizes the digital display circuit of design.

CPLD after programming, as I2C slave devices, and possesses the register of a byte, by changing the value of register, Which passage output I2C clock selected.Such as set 0x01 to select sc0 output I2C clock signals, due to all slave devices It is connected directly with the SDA of main equipment.Therefore the passage of clock output is chosen, main equipment can directly access corresponding Slave device.The I2C addresses of CPLD can also program customized, so avoid address conflict.The clock of output I2C leads to The sum in road can also program definition.Compared to pca9548A, the pin that many sdax are occupied is lacked, has simplified design, improved Application flexibility can simultaneously save cost.

In order to preferably implement the such scheme of the utility model embodiment, it is also provided below and implements above-mentioned side for coordinating The relevant apparatus of case.

In some embodiments, a kind of interchanger, including processor and CPLD chips are also provided, are integrated with the processor Bus master unit, the CPLD chips are connected with the bus master unit by I2C buses, are formed such as foregoing embodiments institute The programmable I2C multiple selector stated.

To sum up, the utility model provides a kind of programmable I2C multiple selector, and may be programmed I2C multichannels including this The interchanger of selector.In technical solutions of the utility model, it is connected using CPLD chips with processor, it is more forms programmable I2C Road selector, can will expand to multichannel for example more than eight road SDx/SCx down going channels by SDA/SCL data feedback channels all the way, solve Existing PCA9548A can only will the problem of data feedback channel expands to eight pairs of down going channels all the way, in this way, to 24 mouthfuls, 48 mouthfuls it The interchanger of class, it is not necessary to use multiple PCA9548A, it is only necessary to which a CPLD chip can be achieved, and use less SDA Pin, so that, design has been simplified, has reduced product complexity, has improved application flexibility, and cost can be saved.

In the above-described embodiments, the description to each embodiment all emphasizes particularly on different fields, and is not described in some embodiment Part, may refer to the associated description of other embodiments.

Above-described embodiment is only to illustrate the technical solution of the utility model, rather than its limitations；The common skill of this area Art personnel should be understood：It can still modify the technical solution described in the various embodiments described above, or to its middle part Technical characteristic is divided to carry out equivalent substitution；And these modifications or replacement, the essence of appropriate technical solution is departed from this practicality The spirit and scope of new each embodiment technical solution.

Claims

A kind of 1. programmable I2C multiple selector, it is characterised in that including：

Complex programmable logic device (CPLD) chip and the processor for being integrated with bus master unit, CPLD chips and described Bus master unit is connected by I2C buses, and the I2C buses are made of data cable SDA and clock cable SCL, described SCL input terminals are expanded to n SC output terminal by CPLD chips, so that, n roads SDx/ will be expanded to by SDA/SCL data feedback channels all the way SCx down going channels, n are positive integer, x=0,1 ... ... n.
2. programmable I2C multiple selector according to claim 1, it is characterised in that

The SDA forms the n roads SDx/SCx down going channels, the n SC outputs with the n SC output terminal expanded respectively The SC output terminals respectively as the n roads SDx/SCx down going channels are held, the SDA is directly as the n roads SDx/SCx downlinks The SD output terminals of passage.
3. programmable I2C multiple selector according to claim 2, it is characterised in that

When for extending fiber optic network passage, the n roads SDx/SCx down going channels connect n fiber optic network mouth respectively.
4. programmable I2C multiple selector according to claim 3, it is characterised in that n is the positive integer more than 8.
5. programmable I2C multiple selector according to claim 3, it is characterised in that the CPLD chips connect 3.3V electricity Source.
6. programmable I2C multiple selector according to claim 3, it is characterised in that the bus master unit is I2CSMBus master。
7. programmable I2C multiple selector according to claim 3, it is characterised in that the programmable I2C multi-path choices Device is with a switch.
8. a kind of interchanger, including processor and CPLD chips, it is characterised in that bus master list is integrated with the processor Member, the CPLD chips are connected with the bus master unit by I2C buses, are formed as claimed in claim 1 programmable I2C multiple selector.