JP2000332791A - Transmission device, and device and system for serial bus intermediate-distance optical transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable intermediate-distance transmission exceeding the upper limit of the standards of a universal serial bus(USB), without using hubs which are installed at specific distance intervals by constituting the optical transmission line of the USB first and then constituting a bridge between the USB and optical transmission line. SOLUTION: A host 20 of USB is connected to a tranceiver 1 of the optical transmission line. The tranceiver 1 is connected to a serial interface engine(SIE) 2 and then connected downstream to an optical encoder 11, an electro-optical signal conversion circuit (E/O) 12, an optical fiber 13, an optoelectric signal conversion circuit (O/E) 14, a decoder 15, and downstream side SIE 2. Furthermore, it is connected upstream in the opposite direction with the same constitution. The downstream SIE 2 is connected to a function 21 via a downstream transceiver 1. Consequently, intermediate-distance transmission is enabled without using an amplifier equivalent to a hub at a distance of 10 m of the optical fiber 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a serial bus signal,
In particular, the present invention relates to an apparatus for transmitting a USB standard signal of 30 m or more.

[0002]

2. Description of the Related Art Universal serial bus
USB) standard is a standard keyboard, mouse,
A personal computer (hereinafter, PC) such as a modem, a printer, a floppy disk, etc.
This is an interface standard that uses a conventional serial signal transmission procedure without using the conventionally used keyboard signal, mouse signal, serial signal, parallel signal, and floppy disk interface signal.

Conventionally, the USB standard has been determined only for transmission using electric signals. Although this standard was created by the standard drafting group, it is a de facto standard that other members can download and view from the World Wide Web (WWW) USB homepage.

[0004] Other technologies related to USB include those disclosed in JP-A-6-324988,
Many others are known.

[0005] The USB is characterized in that the PC automatically recognizes the peripheral device simply by connecting the USB electric signal cable connected to the USB-compatible peripheral device to the USB-compatible PC, and is standardly mounted on the PC. It is characterized in that necessary ones of the drivers are automatically loaded so that peripheral devices can operate automatically. This allows P
The connection between C and the peripheral device can be easily made with the same feeling as the connection between AV devices.

[0006] As a conventional technique, a transmission method using an electric signal will be described below. FIG. 9 shows a maximum configuration diagram of a conventional USB.

The maximum configuration of the USB is determined by the host 100, the most upstream hub 101, the next hub 102, the next next hub 103, the next next hub 104, the most downstream hub 105, and the function 106. The transmission path 107 includes an upstream connector 108, a USB cable 109, and a downstream connector 1.
The maximum USB configuration has six transmission lines.

[0008]

In the conventional example, a hub and an electric cable are used as described above. For this reason, it is necessary to add the propagation delay time in consideration of reflection due to the load capacitance of the semiconductor device and the impedance mismatch in addition to the original propagation delay time of the cable, and to determine the sum with a margin. The USB standard includes a high-speed mode and a low-speed mode. Even in the high-speed mode in which data can be transmitted over a longer distance, the transmission path of one stage is set to 5 m or less, and the maximum delay time of the transmission path is specified as 30 nsec.

Next, the case of transmitting a distance longer than 5 m will be described with reference to FIG.

FIG. 9 is regarded as a diagram when an n-stage (n = natural number) USB hub is inserted. USB hubs 101 and 102 each having a transceiver circuit every 5 m of the transmission path 107,
103, 104, and 105 are inserted, and drive capability recovery and waveform shaping are performed. USB hubs 101, 102, 103, 1
The circuits 04 and 105 and the function 106 are composed of a linear circuit and a digital circuit, and naturally cause a circuit delay time. Therefore, the USB standard defines the maximum delay time per hub as 40 nsec, and the response time of a function is 6.5 bit times (= 542 nsec in high-speed mode).
It is prescribed. Further, a 16-bit time (= 1333 nsec in high-speed mode) is defined as the maximum turnaround time between the USB host and the USB function. From the above, if the number of stages of the hub is n, the following equation is established. ((30 × (n + 1)) + 40 × n) × 2 + 542 <1
333 From this equation, n <5.22, and n = 5 stages from the condition that n is a natural number. Therefore, 5m × 5 steps + 5m =
30 m was the maximum USB reach.

As a second problem, as described above, a USB hub must be provided as a repeater every 5 m of the transmission line, and there is a problem in the degree of freedom of installation and the cost.

[0012]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention first configures a USB optical transmission line, and
The problem was solved by forming a bridge between B and the optical transmission line. This allows medium distance transmission of 30 m or more, which is the upper limit of the USB standard, without using a hub every 5 m. In addition, the circuit scale and the number of parts are small, and there is an advantage in terms of cost as compared with using a plurality of hubs.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first invention of the present invention conforms to the USB specification in which only electric signal transmission is defined,
To perform optical transmission. This has the effect that transmission is possible without the intervention of a hub repeater.

According to a second aspect of the present invention, U is connected via a hub.
This is to be able to connect to the SB function and realize optical transmission between the hub and the function.

[0015] With this, the close function and
There is an effect that it is possible to connect to both of the separated functions.

A third aspect of the present invention is that the turnaround time of a loop including a host and the turnaround time of a loop including a function can be separated. This has the effect that distance transmission for twice the turnaround time of the USB standard becomes possible.

According to a fourth aspect of the present invention, it is possible to divide the data into three blocks: a turnaround time of a loop including a host, a turnaround time of a loop including a function, and a turnaround time of a loop including an optical transmission line. . As a result, the optical transmission line can be separated from the restrictions of the turnaround time of the USB standard, and the host and the function conform to the specification range of the turnaround time of the USB specification, so that transmission over an arbitrary distance is possible. There is action.

(Embodiment 1) FIG. 1 is a block diagram for realizing Embodiment 1 of the present invention. The configuration will be described with reference to FIG. The USB host 20 is connected to the transceiver 1 on the optical transmission line. Transceiver 1
Is connected to a serial interface engine (hereinafter abbreviated as SIE) 2, and downstream, an optical encoder 11, an electro-optical signal conversion circuit (hereinafter abbreviated as E / O) 12, an optical fiber 13, and a photoelectric conversion circuit (hereinafter abbreviated as O / O). E), 14,
The decoder 15 is connected to the downstream side SIE2. Here, the encoder 11 and the decoder 15 correspond to Japanese Patent Application No. Hei 10-31.
No. 8726, for example. It has the same configuration in the upstream direction, but is connected in the opposite direction. The downstream SIE 2 is connected to the downstream transceiver 1 and to the function 21.

Next, the operation principle will be described.

FIG. 6 shows the transmission procedure in this embodiment in a time-series manner. USB has four transfer modes: control transfer, bulk transfer, interrupt transfer, and isochronous transfer. As an example, a case where control transfer for transferring packets in both directions, which is always used during USB transfer, will be described.

The control transfer includes a setup transaction for setting up a setup register from the host to the function or hub, an in transaction for inputting function data to the host, and an out transaction for outputting data from the host to the function.

First, a case where a command is transmitted from the host 20 to the function 21 in an out transaction will be described. The host 20 sends an out command. This signal is a differential linear signal. The upstream transceiver 1 converts this signal into a digital signal. The SIE 2 on the upstream side performs a CRC check after locking the signal coming from the transceiver 1 on the upstream side by digital phase loop lock (hereinafter referred to as DPLL). CRC
If no error occurs in the check, nothing is transmitted from SIE2 to the host side. However, when an error is detected by the CRC check, a NACK is sent to the host 20 to prompt the host 20 to retransmit. At this time, the data received by SIE2 is discarded. If there is no problem in the check, the encoder 11 performs encoding described in Japanese Patent Application No. 10-318726, and converts the encoded data into multi-valued data.

The E / O 12 converts the electric signal into an optical signal. The optical fiber 13 is, for example, a 10 m optical transmission line. The O / E 14 converts an optical signal into an electric signal. The decoder 15 performs the decoding described in Japanese Patent Application No. 10-318726. The downstream SIE 2 receives the signal and sends it to the transceiver 1 on the downstream side. This downstream SIE2 is CR
Do not check C. Further, neither ACK nor NACK is issued. The signal output from the transceiver 1 on the downstream side is a USB differential signal and transmitted to the function 21 on the downstream side. The function 21 prepares to return ACK if no error occurs in the CRC check, and prepares to return NACK if an error occurs. Next, a case where ACK or NACK is returned from the function 21 to the host 20 will be described. The ACK transmitted from the function 21 is a differential signal.

This signal is converted into a digital signal by the transceiver 1 and enters the downstream SIE 2. Downstream SIE
Reference numeral 2 locks a signal from the transceiver 1 on the downstream side by a DPLL and then performs a CRC check. If no error occurs in the check, nothing is sent to the function side. However, when a CRC error is detected in the check, a NACK is sent to the function 21 to prompt the host 20 to retransmit. At this time, the downstream S
The IE2 data is discarded. If no error occurs in the check, the encoder 11 uses the Japanese Patent Application No. 10-3187.
Encoding described in No. 26 is performed, and the data is converted into multi-valued data. E / O1
2 converts the electric signal into an optical signal. Optical fiber 13
Is a 10 m optical transmission line, for example. The O / E 14 converts an optical signal into an electric signal. Patent application 10
The decoding described in JP-A-318726 is performed. Upstream SIE
2 receives the signal and sends it to transceiver 1. At this time, the SIE 2 on the upstream side does not check for errors, and neither issues ACK nor NACK.

The signal output from the transceiver 1 on the upstream side is U
This is an SB differential signal, which is provided to the host 20. This completes the out transaction.

Next, a setup transaction will be described. The setup transaction is basically the same as the out transaction, except that the out transaction is the transmission of various commands and data. The difference is that NACK is not returned. Next, an in-transaction will be described. An in-command is transmitted from the host 20 to the function 21. When the IN command is correctly transmitted to the function 21, the reply data is transmitted from the function 21 to the host 20. If there is no CRC error in the data reception, the host 20 transmits ACK to the function 21 and the in-data transmission is completed. When the function 21 causes a CRC error in response to the IN command from the host 20, a NACK is returned. The transmission procedure in the setup transaction and the in-transaction is as shown in FIG. 6, and the detailed description will not be repeated because it is repeated.

As described above, in any transfer mode,
Medium distance transmission is possible without using an amplifier corresponding to a hub between the optical fibers 10m.

(Embodiment 2) FIG. 2 shows Embodiment 2 of the present invention.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

In the first embodiment, an upstream USB hub standard port repeater (hereinafter referred to as a port repeater) 3 and a repeat control 4 for controlling the same are provided between the upstream SIE 2 and the upstream encoder 11 and the decoder 15. This is the configuration to be added. Further upstream port repeater 3
Has a hub repeat function. Port repeater 3
And a plurality of transceivers connected to the

Next, the operation will be described. The middle-distance transmission part is the same as in the first embodiment, and a description thereof will not be repeated. The feature is that, with the port repeater 3 inserted, a plurality of functions 21 can be used in an environment close to the host 20 and the functions 21 can be used in an environment 10 m away from the host 20.

(Embodiment 3) FIG. 3 shows Embodiment 3 of the present invention.

Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

In the second embodiment, a downstream port repeater 3 and a downstream repeat control 4 for controlling the downstream port repeater 3 are added between the downstream SIE 2 and the downstream encoder 11 and decoder 15. Function 2 from downstream port repeater 3 via transceiver 1
1 is connected.

Next, the operation will be described. The middle-distance transmission part is the same as in the second embodiment, and a description thereof will be omitted. The feature is that a plurality of functions 21 can be used in an environment far from the host 20 by entering the downstream port repeater 3.

(Embodiment 4) FIG. 4 shows Embodiment 4 of the present invention.

Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.

In the second embodiment, the upstream port repeater 3 and the upstream repeat control 4 are replaced with a buffer 5 and a microcontroller 6, respectively.

Next, the operation will be described. FIG. 7 shows a transmission procedure in the present embodiment in chronological order. US
B has control transfer, bulk transfer, interrupt transfer,
There are four transfer modes of isochronous transfer. USB
It is always used at the time of transfer, and the case of control transfer for transferring bidirectional packets will be described as an example. The control transfer includes a setup transaction for setting up a setup register from the host controller to the function or the hub, an in transaction for inputting data from the function to the host, and an out transaction for outputting data from the host to the function.

First, a case where data is transmitted from the host 20 to the function 21 in an out transaction will be described. The host 20 sends an out command. This signal is a differential linear signal. Transceiver 1
Converts this signal to a digital signal. The SIE 2 locks the signal coming from the transceiver 1 by the DPLL and performs a CRC check. If no error occurs in the check, an ACK is transmitted to the host.

However, when a CRC error is detected, a NACK is transmitted to the host, thereby prompting the host to retransmit. When a NACK is returned, it is not transmitted to the buffer 5. When no error occurs, the data is transmitted to the buffer 5, and the buffer 5 transmits the data to the encoder 11. The encoder 11 performs encoding described in Japanese Patent Application No. 10-318726 and converts it into multi-valued data. The E / O 12 converts the electric signal into an optical signal. The optical fiber 13 is, for example, a 10 m optical transmission line. The O / E 14 converts an optical signal into an electric signal.

The decoder 15 is disclosed in Japanese Patent Application No. Hei 10-318726.
The decoding of the number is performed. The downstream SIE 2 receives the signal and sends it to the transceiver 1 on the downstream side. This downstream SIE2 does not perform a CRC check. Therefore AC
Neither K nor NACK is issued. The signal output from the transceiver 1 on the downstream side is a USB differential signal, and is supplied to the function 21. The function 21 performs a CRC check and prepares to return ACK if no error occurs, and prepares to return NACK if an error occurs. Next, a case where ACK or NACK is returned from the function 21 to the host 20 will be described. The ACK transmitted from the function 21 is a differential signal. This signal is converted into a digital signal by the transceiver 1 on the downstream side, and enters the SIE 2 on the downstream side.

The downstream SIE 2 encodes a signal coming from the downstream transceiver 1 by the encoder 11,
Convert to multi-value. The E / O 12 converts the electric signal into an optical signal. The optical fiber 13 is, for example, a 10 m optical transmission line. The O / E 14 converts an optical signal into an electric signal. The decoder 15 decodes the signal into a USB signal. The buffer 5 receives the signal. If the signal is ACK according to the instruction of the microcontroller 6, the buffer 5 empties the contents of the buffer 5 and waits for reception of data from the next host 20.
If NACK, the data temporarily stored in the buffer 5 is retransmitted to the function 21.

Next, a setup transaction will be described. The setup transaction is basically the same as the out transaction, except that the out transaction is the transmission of general commands and data, whereas the setup transaction is that only the setup command and setup data are transmitted. The difference is that a transaction does not return a NACK.

Next, regarding the in-transaction, the in-command is transmitted from the host 20 to the function 21. If the host 20 cannot correctly transmit to the upstream SIE2 in the in command, a NACK or STALL is transmitted from the upstream SIE2 to the host 20. When the upstream SIE 2 receives the CRC command without causing a CRC error, it sends an IN command to the buffer 5 without returning anything to the host 20. The buffer 5 passes the in-command to the encoder 11 in the downstream direction. The transmission procedure from here to the function 21 is the same as the above-mentioned out-transaction, so that the description is omitted. When the function 21 correctly receives the IN command, the function 21 transmits the response data to the buffer 5. If the In command cannot be received correctly or a CRC error occurs, the STALL or NACK command is stored in the buffer 5
Send to The buffer 5 returns the response data to the host 20 according to the instruction of the microcontroller 6. When the buffer 5 receives the NACK and the STALL, the in-command stored in the buffer 5 is transferred to the function 2
Retransmit to 1. The host 20 transmits ACK to the function 21 when no error occurs in the response data. In this embodiment, between the host 20 and the upstream side SIE2, the maximum value 133 of the USB standard turnaround time is set.
Limited by 3 nsec. Between the function 21 and the upstream side SIE2 is also limited by the maximum value of the turnaround time of 1333 nsec of the USB standard.

(Fifth Embodiment) FIG. 5 shows a fifth embodiment of the present invention.

Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings.

The configuration will be described below. In the fourth embodiment, a downstream buffer B5 and a downstream microcontroller B6 are added between the downstream SIE2 and the downstream encoder 11 and the decoder 15.

Next, the operation will be described. FIG. 8 is a diagram for explaining the operation. The difference from the fourth embodiment is that the insertion of the buffer B5 establishes two bridges and forms a turnaround loop independent of the USB standard. Since the fourth embodiment can be described by repeating the fourth embodiment on the downstream side, detailed description is omitted. As a feature, host 2
The maximum value of the USB turnaround time between 0 and the upstream SIE2 is 1333 nsec. Function 21 is USB between SIE2 on the downstream side
Is limited to a maximum value of 1333 nsec. The turnaround time can be set between the upstream SIE2 and the downstream SIE2 irrespective of the USB standard, and a longer distance optical fiber can be used. In this example, a 100 m optical fiber is used.

As described above, transmission can be performed without using an amplifier corresponding to a hub between the optical fibers 100m.

[0051]

As described above, the present invention has an effect that a serial bus signal such as a USB signal, which can be transmitted only within 30 m or less according to the prior art, can be transmitted over 30 m.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a serial bus middle-distance optical transmission device according to a first embodiment of the present invention;

FIG. 2 is a block diagram showing a serial bus middle distance optical transmission system according to a second embodiment of the present invention;

FIG. 3 is a block diagram showing a serial bus medium-distance optical transmission system according to a third embodiment of the present invention;

FIG. 4 is a block diagram showing a serial bus middle distance optical transmission system according to a fourth embodiment of the present invention;

FIG. 5 is a block diagram showing a serial bus middle distance optical transmission system according to a fifth embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of the serial bus medium-distance optical transmission device according to the first embodiment of the present invention.

FIG. 7 is a diagram for explaining the operation of a serial bus medium-distance optical transmission system according to a fourth embodiment of the present invention;

FIG. 8 is a diagram illustrating an operation of a serial bus medium-distance optical transmission system according to a fifth embodiment of the present invention.

FIG. 9 is a block diagram showing a physical model of a conventional USB electric signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transceiver 2 SIE (Serial Interface Engine) 3 Port repeater 4 Repeat control 5 Buffer 6 Microcontroller 20 Host 21 Function

Claims (14)

[Claims] An encoder that encodes an input serial bus signal into a signal suitable for optical transmission, an electro-optical signal conversion circuit that converts a signal output from the encoder from electricity to an optical signal, and transmits an optical signal. An optical fiber transmission line, a photoelectric conversion circuit for converting a transmitted optical signal from light to an electric signal, and a decoder for converting an input electric signal to a serial bus signal, for converting a serial bus signal to light. A transmission device characterized in that the transmission is performed. 2. An upstream transceiver defined by the USB standard, an upstream serial interface engine defined by the USB standard connected to the transceiver, and a signal output from the serial interface engine transmitted downstream. The transmission device of claim 1,
2. The transmission device according to claim 1, which transmits a signal input to said serial interface engine from a downstream direction, a downstream serial interface engine connected to said two systems of transmission devices, and a downstream transceiver connected thereto. , And converts a serial bus signal to light and transmits the light. 3. An upstream transceiver, an upstream serial interface engine connected to the transceiver, a USB hub standard port repeater connected to the serial interface engine, and a repeat control for controlling the port repeater. A transmission device for transmitting a signal output from the port repeater in a downstream direction, a transmission device for transmitting a signal input to the port repeater from a downstream direction,
A plurality of transceivers 1 connected to the port repeater 3, a downstream serial interface engine connected to the two transmission systems, and a downstream transceiver connected thereto; A serial bus medium-distance optical transmission device, which converts an optical signal into light and transmits the light. 4. An upstream transceiver, an upstream serial interface engine connected to the transceiver, a USB hub standard port repeater connected to the serial interface engine, and a repeat control for controlling the port repeater. A transmission device for transmitting a signal output from the port repeater in a downstream direction, a transmission device for transmitting a signal input to the port repeater from a downstream direction,
A downstream port repeater connected to the two transmission systems, a repeat control for controlling the port repeater, a downstream serial interface engine connected to the downstream port repeater, and connected thereto. A serial bus medium-distance optical transmission device, comprising: a plurality of downstream transceivers; and converting a serial bus signal into light. 5. An upstream transceiver, an upstream serial interface engine connected to the transceiver, a buffer having a function similar to an end-of-point of a USB function connected to the serial interface engine, and the buffer A microcontroller for controlling, a transmission device for transmitting a signal output from the buffer in a downstream direction, a transmission device for transmitting a signal input to the buffer from a downstream direction, and the transmission device. A serial bus mid-range optical transmission device, comprising: a downstream serial interface engine connected to a transmission device of a system; and a downstream transceiver connected to the transmission interface device, and converting a serial bus signal into light. . 6. An upstream transceiver, an upstream serial interface engine connected to the transceiver, an upstream buffer A connected to the serial interface engine, and an upstream microcontroller for controlling the buffer A. 2. The transmission device according to claim 1, which transmits a signal output from the buffer A in a downstream direction, the transmission device transmits the signal input to the buffer A from a downstream direction, and A downstream buffer B connected to the transmission device of the system, a microcontroller B for controlling the buffer B, a downstream serial interface engine connected thereto,
And a downstream transceiver connected thereto for converting a serial bus signal into light. 7. A USB host, a serial bus medium-distance optical transmission device according to claim 2, and a USB function, wherein the serial bus signal between the host and the function is converted into light. Features a serial bus medium-distance optical transmission system. 8. A serial bus comprising a USB host, the serial bus medium-distance optical transmission device according to claim 3, and a plurality of USB functions, converting a serial bus signal between the host and the functions into light. A serial bus medium-distance optical transmission system. 9. A serial bus signal between the host and the plurality of functions, comprising a USB host, the serial bus medium distance optical transmission device according to claim 4, and a plurality of USB functions. A medium-range serial bus optical transmission system characterized by converting light into light. 10. A USB host, the serial bus medium-distance optical transmission device according to claim 5, and a USB function, wherein the serial bus signal between the host and the function is converted into light. Features a serial bus medium-distance optical transmission system. 11. A USB host, the serial bus medium-distance optical transmission device according to claim 6, and a USB function, wherein the serial bus signal between the host and the function is converted into light. Features a serial bus medium-distance optical transmission system. 12. A USB host, a USB hub,
7. A serial bus medium-distance optical transmission device according to claim 6, further comprising:
A function of converting the serial bus signal between the host and the function into light. 13. A USB host, the serial bus medium distance optical transmission device according to claim 6, a USB hub, and a USB hub.
A function of converting the serial bus signal between the host and the function into light. 14. The serial bus medium-distance optical transmission device according to claim 1, wherein the serial bus signal is a USB standard signal.