JP2008107997A5 - - Google Patents

Description

Data communication method, data communication apparatus, and data communication system

  The present invention relates to a USB data communication method, a data communication apparatus, and a data communication system which are performed via a plurality of logical data channels set between a host computer and a data communication apparatus.

  USB (Universal Serial Bus) is well known as a standard for data transmission paths connecting devices such as a keyboard, mouse, modem, and joystick to a host computer. USB 1.1 is known as a standard for connecting a device that does not exchange a large amount of data with a host computer. However, in recent years, USB 2.0 ( HI-SPEED USB) has been formulated.

  Here, a data transfer method adopting the USB standard will be briefly described with reference to FIG. When the host computer and the USB device are physically connected by a USB cable, a logical communication path is set apart from the physical communication path, and data is transferred between the host computer and the USB device. This is done via this logical communication path. A memory area for storing data to be transmitted and received is set in advance in the USB device. This memory area is generally called an endpoint buffer, and a USB device can have a plurality of endpoint buffers, and each endpoint buffer and the host computer are connected by a logical communication path. By grouping a plurality of endpoint buffers, a unit called an interface can be obtained.

  Patent Document 1 discloses a peripheral device (printer) that includes an endpoint buffer that includes an asynchronous transfer buffer, a synchronous transfer buffer, and a data transfer method notification buffer. Here, the host computer and the printer are configured to be communicably connected via three logical communication paths corresponding to these three buffers.

  The host computer accesses using the USB address of the device and the endpoint number, and polls each endpoint buffer. Patent Document 2 discloses a method of polling a plurality of data channels at predetermined intervals.

  With reference to FIGS. 6 and 7, a data communication method between a host computer and a device having a total of four endpoint buffers, that is, endpoint buffer 0 to endpoint buffer 3, will be described. In the following description, a logical communication path configured between each endpoint buffer and the host computer is referred to as a data channel.

The following description is based on the assumption that transmission data is stored only in the endpoint buffer 1. The host computer sequentially issues data transmission requests to the endpoint buffer 0 to the endpoint buffer 3 of the device. First, at T100, a data transmission request 1 is made to the endpoint buffer 0, but since there is no transmission data in the endpoint buffer 0, a data transmission request 2 to the endpoint buffer 1 is made next (T101). Since transmission data is stored in the endpoint buffer 1 , the transmission data is transferred from the endpoint buffer 1 to the host computer (T102). Subsequently, the data request 3 is made to the endpoint buffer 2 (T103), but since there is no transmission data in the endpoint buffer 2, the next data transmission request 4 is made to the endpoint buffer 3 (T104). ) Since there is no transmission data in the endpoint buffer 4, the data transmission request 1 is again made to the endpoint buffer 0 (T105). In this way, by polling each endpoint buffer, it is determined whether there is transmission data transferred via each data channel.

JP 2003-248558 A JP-T-2004-515966

  However, in the conventional data communication method in which all endpoint buffers are polled and transmission data is transmitted if there is an endpoint buffer in which transmission data is stored, the endpoint is determined depending on how the interface is designed. When the number of buffers is increased or the number of data channels is increased, the number of polling increases in proportion thereto, which causes a problem that the communication load increases and the communication performance is deteriorated.

  The present invention has been made in view of such circumstances, and in data communication performed via a plurality of logical data channels set between a host computer and a data communication device, data transfer with good communication performance is performed. The purpose is to do.

The above problem can be solved by the following means.
The present invention is a USB data communication method performed via a plurality of logical data channels set between a host computer and a data communication device,
The host computer periodically inquires the data communication device via any one of the plurality of logical data channels,
In response to the inquiry , the data communication apparatus transmits a communication status including a device transmission state indicating presence / absence of transmission data to be transmitted to the host computer, to the host computer ,
When the host computer determines that the transmission data exists based on the device transmission state , the host computer transmits a transmission data transmission request to the data communication device ,
The data communication apparatus, and transmits the transmission data through the corresponding data channel to the host computer.

  According to the above configuration, the host computer makes an inquiry through one data channel among a plurality of data channels, and determines whether there is transmission data from the device transmission state included in the communication status transmitted in response to the inquiry. It is configured. Accordingly, since it is not necessary to make an inquiry for every data channel, the communication load can be reduced. In addition, when there is transmission data, a data transmission request is made from the host computer via the corresponding data channel, so even if the number of data channels is increased, it is possible to transfer data without degrading communication performance. It is.

In the data communication system, the data communication apparatus transmits the transmission data to the host computer in descending order of priority among the corresponding data channels.

  According to the above configuration, even when there are a plurality of transmission data, the transmission data is transmitted from the host computer via the corresponding data channel in the order of the transmission priority. It is possible to use the data channel efficiently.

Further, the present invention is a data communication apparatus for performing USB data communication via a plurality of logical data channels set with a host computer,
A plurality of transmission data storage areas in which transmission data to be transmitted to the host computer are stored and set to correspond to the data channel, and a device indicating whether or not the transmission data is stored in each transmission data storage area A communication status generation unit that generates a communication status including a transmission state, and
The transmission data is transmitted from a transmission data storage area in which the transmission data is stored in response to a transmission data transmission request from the host computer.
The present invention also provides a data communication system comprising a host computer and a data communication device that performs USB data communication via a plurality of logical data channels set between the host computer. ,
The data communication device includes:
A plurality of transmission data storage areas in which transmission data to be transmitted to the host computer are stored and set to correspond to the data channel, and a device indicating whether or not the transmission data is stored in each transmission data storage area A communication status generation unit for generating a communication status including a transmission state, and transmitting the transmission data from a transmission data storage area in which the transmission data is stored in response to a transmission data transmission request from the host computer. Features.

  According to the above configuration, the data communication apparatus includes the communication status generation unit that generates a communication status including a device transmission state indicating whether or not transmission data is stored in each transmission data storage area. Therefore, the host computer can confirm the presence / absence of transmission data only by receiving the communication status. As a result, it is not necessary to make an inquiry for every data channel one by one, so that the communication load can be reduced. Furthermore, since transmission data is transmitted through the corresponding data channel in response to a transmission data transmission request from the host computer only when there is transmission data, communication performance is not degraded even if the number of data channels is increased. It is possible to transfer data.

  In the present invention, transmission priority of transmission data is set in the data channel, and the transmission data is stored according to the transmission priority in response to a transmission data transmission request transmitted from the host computer. The transmission data is transmitted from the transmitted data storage area.

  According to the above configuration, even when the transmission data is stored in a plurality of data storage areas, the transmission data can be transmitted through the corresponding data channel in the descending order of transmission priority. Even in such a case, it is possible to efficiently use a plurality of data channels.

Hereinafter, embodiments of a data communication method, a data communication apparatus, and a data communication system according to the present invention will be described with reference to the drawings. Note that a USB device connected to a host computer will be described as an example of the data communication apparatus. FIG. 1 is a schematic diagram showing a data communication system 200 of the present embodiment.
As shown in FIG. 1, in this embodiment, the label printer 20, the media drive 30, and the media transport mechanism 40 are connected via a hub 11 that is a branch device for connecting a plurality of USB devices to the USB port of the host computer 100. Are connected so that they can communicate. The label printer 20 performs label printing on one side of a medium such as a CD / DVD, the media drive 30 writes data on the other side of the medium, and the media transport mechanism 40 drives the transport arm to connect these USB devices and media. Media is transported to and from the stacked media stacker.
In this embodiment, the label printer 20, the media drive 30, and the media transport mechanism 40 are covered by a housing (not shown) to form the media processing device 10 that writes data to the media and performs label printing.

  Hereinafter, USB data communication performed between the host computer 100 and the media transport mechanism 40 will be described. First, an internal configuration of a general USB device will be described based on FIG. 6 referred to in the description of the background art.

  USB data transfer is performed in such a manner that the host computer periodically makes a data transmission request to the USB device (polling), and the device responds to the data transmission request. In the case of USB, there are many cases where a plurality of devices are connected to a host computer. Therefore, the CPU of each device does not respond to a data transmission request, but uses the concept of an endpoint, and hosts each endpoint. Polling and data transfer from the computer.

  Here, the endpoint is generally a FIFO (First In First Out) buffer memory, and USB data transfer is configured between the host computer and each endpoint (endpoint buffer 0 to endpoint buffer 3). Logical channels (data channel 0 to data channel 3 are used.

  Normally, the endpoint buffer 0 configures a bidirectional data channel 0 used for device configuration and basic information exchange with the host computer, and the other endpoint buffers 1 to 3 are The unidirectional data channel 1 to data channel 3 are configured. Note that the number of endpoint buffers, the number of data channels, the data transfer direction, and the like can be freely set on the device side.

(About internal processing of USB device in this embodiment)
Next, the internal configuration of the media transport mechanism that is a USB device in the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram for explaining the internal processing of the media transport mechanism in the present embodiment.

  As described above, the media transport mechanism 40 is set with the host computer 100 in which the endpoint buffer 0 that constitutes a bidirectional data channel used for device configuration and basic information exchange is set. In the embodiment, a data channel 1 and a data channel 4 are configured as a bidirectional communication path between the endpoint buffer 0 and the host computer 100.

The data channel 1 is a communication path through which commands and responses to the media transport mechanism 40 are transferred from the host computer 100. For example, a transfer arm movement command (not shown), a power ON notification from the media transfer mechanism 40 , a power OFF notification, a communication status request (inquiry) periodically issued from the host computer, and the like are transferred via the data channel 1. . Further, when there is transmission data in the media transport mechanism 40, a transmission data transmission request transmitted from the host computer 100 is also transferred via the data channel 1. On the other hand, in the data channel 4, a real time command and a response to the real time command are transferred.

  Further, an endpoint buffer 1 and an endpoint buffer 2 that form a unidirectional data channel are set between the host computer 100 and the host computer 100. In this embodiment, the data channel 3 is a unidirectional communication path from the host computer 100 to the endpoint buffer 1, and the data channel 0 and the data channel 2 are unidirectional communication paths from the endpoint buffer 2 to the host computer 100. Is configured.

The data channel 3 is a channel used for transferring rewritten data from the host computer 100 to the media transport mechanism 40 when the firmware included in the media transport mechanism 40 is rewritten.
The data channel 0 is used to transfer the communication status of the media transport mechanism 40 described later to the host computer 100.
Further, the data channel 2 is a channel to which a status for automatically notifying the host computer of the change every time the state of the media transport mechanism 40 changes (hereinafter referred to as “auto status back”) is transferred. .

  As described above, the media transport mechanism 40 according to the present embodiment includes the interface 41 with a total of three buffers of the endpoint buffer 0 to the endpoint buffer 2 as one group.

Each endpoint buffer is connected to the report data generation unit 42. The report data generation unit 42 generates report data that is a transfer unit of data transfer performed through each data channel. FIG. 3 shows a report data format.
As shown in FIG. 3, the report data 50 includes a report ID 51, a channel number 52, a valid byte number 53, and a data part 54. The data part 54 is an area where data to be actually transferred is defined. Specifically, a command and a response to the command, an auto status, a communication status, a real-time command and a response to the command, firmware rewrite data, and the like are defined.

  The number of valid bytes 53 defines the number of valid bytes of data defined in the data portion 54. In the channel number 52, any number of the data channel 0 to the data channel 4 is defined according to the use of data defined in the data portion 54, the data destination, and the data priority. The report ID 51 is defined according to the length of data defined in the data part 54. When the report ID is defined, the maximum value of the number of valid bytes of data is determined.

The report data generation unit 42 generates report data in response to a data transmission request from the host computer 100 or a communication status request, and transfers the report data to the host computer 100. Also, each endpoint buffer is monitored for the presence of transmission data, and if there is an inquiry about the communication status, "transmission data is present" if the transmission data is stored, and "transmission" if the transmission data is not stored A communication status including “no data” is generated, and the communication status is generated as a transfer format of the report data 50. Incidentally, the communication status shows the Contact only that data transmission state to each endpoint buffers of the media transportation mechanism 40.

(About data transfer processing in this embodiment)
Next, a data transfer process performed between the host computer 100 and the media transport mechanism 40 according to the present embodiment will be described. FIG. 4 is a flowchart for explaining data transfer processing performed between the host computer 100 and the media transport mechanism 40. FIG. 4A shows processing on the host computer side, and FIG. The processing on the media transport mechanism side is shown. FIG. 5 is a time chart for explaining data transfer processing performed between the host computer 100 and the media transport mechanism 40.

Here, for example, a case where transmission data is stored in the endpoint buffer 2 will be described as an example.
First, in order to confirm the data transmission state of each endpoint buffer of the media transport mechanism 40, when a communication status transmission request is transferred from the host computer 100 via the data channel 1 (step S11: T1), the communication status The transmission request is stored in the endpoint buffer 0 (step S11a) . When the report data generation unit 42 confirms the transmission request for the communication status of the endpoint buffer 0, the report data generation unit 42 confirms whether there is transmission data in the endpoint buffer 0 to the endpoint buffer 2, and generates report data.

  At this time, the report data generation unit 42 defines a communication status indicating “there is transmission data” in the data portion 54 of the report data 50, and defines a data channel 0 in the channel number 52 as a data channel for transferring the communication status. Then, report data is generated and transmitted to the host computer 100 via the data channel 0 (step S12: T2).

When receiving the report data (step S12a) , the host computer 100 determines that there is transmission data based on the communication status (step S13: Yes), and transmits the transmission data via the data channel 1 to request the transmission data. The request is transferred (step S14: T3). When the endpoint buffer 0 receives the transmission data transmission request (step S14a) , the transmission data is transferred from the endpoint buffer 2 storing the transmission data to the host computer 100 via the data channel 2 (step S15: T4). The host computer 100 receives the transmission data (step S16) .

Returning to step S11, when the regular communication status request via the data channel 1 from the host computer 100 is transmitted (T5), carried out from the step S12 repeats the processing in step S1 6, when there is transmission data, corresponding transmission data over a data channel which is transferred, when there is no transmission data (step-up S13: no), it waits for communication status request from the host computer 100 sent again (step S11), and repeatedly performs the process of step S1 6 from step S12.

Note that when there are a plurality of transmission data in the endpoint buffer, it can be dealt with by setting the data transfer priority in the data channel. In the present embodiment, if the data channel 2 is set to the first priority, data transfer can be performed with priority over other data channels.

As described above, according to the data transfer method described in the present embodiment, the data transmission state of the endpoint buffer can be confirmed by the communication status. Accordingly, since it is not necessary to poll each endpoint buffer as in the prior art, the communication load is reduced and data transfer with good performance can be performed.
Furthermore, the host computer 100 transfers the transmission request for transmission data only when it can be confirmed that there is transmission data in the end point buffer of the media transport mechanism 40, so the frequency of the transmission request is reduced, and the host computer 100 Can reduce the processing load.

It is the schematic which showed the data communication system of this embodiment. It is a block diagram for demonstrating the internal process of the media conveyance mechanism in this embodiment. It is the schematic of the format of report data. 6 is a flowchart for explaining data transfer processing performed between a host computer and a media transport mechanism. (A) shows processing on the host computer side, and (b) shows processing on the media transport mechanism side. It is a time chart explaining the data transfer process performed between a host computer and a media conveyance mechanism. It is a block diagram which shows the internal structure of a general USB device. It is a time chart explaining the conventional data transfer process performed between a host computer and a media conveyance mechanism.

10: Media processing device, 20: Label printer, 30: Media drive, 40: Media transport mechanism, 41: Interface, 42: Report data generation unit, 50: Report data, 51: Report ID, 52: Channel number, 53: Number of valid bytes, 54: Data part

Claims (6)

A USB data communication method performed via a plurality of logical data channels set between a host computer and a data communication device,
The host computer periodically inquires the data communication device via any one of the plurality of logical data channels,
In response to the inquiry , the data communication apparatus transmits a communication status including a device transmission state indicating presence / absence of transmission data to be transmitted to the host computer, to the host computer ,
When the host computer determines that the transmission data exists based on the device transmission state , the host computer transmits a transmission data transmission request to the data communication device ,
The data communication apparatus, data communication method, characterized by transmitting the transmission data via the corresponding data channel to the host computer. The data communication method according to claim 1, wherein the data communication apparatus transmits the transmission data to the host computer in descending order of priority among the corresponding data channels. A data communication device that performs USB data communication via a plurality of logical data channels set with a host computer,
A plurality of transmission data storage areas in which transmission data to be transmitted to the host computer are stored and set to correspond to the data channel;
A communication status generation unit that generates a communication status including a device transmission state indicating whether or not the transmission data is stored in each transmission data storage area, in response to a transmission data transmission request from the host computer, A data communication apparatus, wherein the transmission data is transmitted from a transmission data storage area in which transmission data is stored. A transmission priority of transmission data is set for the data channel,
4. The transmission data is transmitted from a transmission data storage area in which the transmission data is stored according to the transmission priority in response to a transmission data transmission request transmitted from the host computer. Data communication equipment. A data communication system comprising: a host computer; and a data communication device that performs USB data communication via a plurality of logical data channels set between the host computer,
The data communication device includes:
A plurality of transmission data storage areas in which transmission data to be transmitted to the host computer are stored and set to correspond to the data channel;
A communication status generation unit that generates a communication status including a device transmission state indicating whether or not the transmission data is stored in each transmission data storage area,
A data communication system, wherein the transmission data is transmitted from a transmission data storage area in which the transmission data is stored in response to a transmission data transmission request from the host computer. A transmission priority of transmission data is set for the data channel,
6. The transmission data is transmitted from a transmission data storage area in which the transmission data is stored according to the transmission priority in response to a transmission data transmission request transmitted from the host computer. Data communication system.