JP3906838B2 - USB compatible digital MFP - Google Patents

Description

The present invention relates to an improvement of a USB compatible digital multi-function peripheral that can be used as a printer / scanner by connecting a host computer via a USB interface.

In general, a USB-compatible device can have endpoints EP0 to EP15 for data transfer with a host according to the standard. In particular, in a USB-compatible multifunction device, device interfaces corresponding to each function are determined by endpoints that do not overlap each other. In order to configure, many end point resources are required, and a USB controller having a large number of end points has to be adopted.
For example, in a multifunction device having the functions of a GDI compatible printer and a TWAIN compatible scanner, the device interface corresponding to the printer unit uses the endpoint EP1 for data transmission and the endpoint EP2 for data reception. In the corresponding device interface, the endpoint EP3 is used for data transmission, and the endpoint EP4 is used for data reception. When the device is set up with the endpoint EP0 used for control transfer, a total of five is used. Endpoint resources were being used.
Therefore, in Patent Document 1, it is proposed that a buffer for an endpoint is configured with a single buffer that is commonly used for the endpoints EP0 to EP2 for such resources related to the endpoint. 2, in response to the case where a plurality of types of information including the first and second information are assigned as the information transferred by the data transfer device via one endpoint, the first information for the first information It teaches and proposes that one storage area and a second storage area for second information have buffers prepared corresponding to one endpoint.
However, none of the above-mentioned patent documents pays attention to the effective use of the end point of a multifunction peripheral having two or more functions.
JP 2001-134528 A JP 2002-344537

  According to the present invention, in a USB compatible digital multi-function peripheral, the number of endpoint resources required for the configuration of the USB controller is suppressed, so that a low-cost, low-cost USB controller with a simple configuration can be used. The purpose is to provide a digital multifunction device.

In order to solve the above-mentioned problem, according to claim 1 of the present invention , data according to a predetermined communication protocol with a host computer is installed in order to execute a function of a plurality of types of peripheral devices. The endpoint is assigned to the data transfer for each function so that the device interface is transmitted and received, and used for the control transfer when configuring the device interface among the USB controller configuring the device interface and the multiple endpoints equipped in the USB controller. After the device interface is constructed, the bidirectional endpoint is provided with a control unit that allocates data transfer for executing a function of at least one peripheral device among a plurality of types of peripheral devices .

According to a second aspect of the present invention, after the device interface is configured , the control unit transmits each of data transferred to execute the functions of two peripheral devices among the plurality of types of peripheral devices to the bidirectional endpoint. to correspond to the transfer direction has to allocate, in claim 3, further defined in claim 2, control means transfers data assigned to bidirectional endpoints, copy, printer, scanner, camera, facsimile Two pieces of image data for transmission / reception, their commands, and response signals whose transfer directions are opposite to each other are specified. Note that the composite function here is not limited to only the copy, printer, scanner, camera, and facsimile, and even if it is another function, the technical concept of the present invention is applicable as long as the transfer direction of the transfer data is opposite. Is applicable.

According to the first to third aspects of the present invention, the bidirectional endpoint used for the control transfer at the time of configuring the device interface is used to execute the function of at least one peripheral device after the device interface is constructed. Since the method of assigning data transfer is adopted, the endpoint resource can be effectively used on the USB controller side. Therefore, the USB controller to be incorporated in the digital multifunction peripheral can be made inexpensive and simple in configuration.

  Hereinafter, a printer / scanner multifunction device will be described as an example of a USB-compatible digital multifunction device according to the present invention with reference to the drawings.

FIG. 1 is a block diagram illustrating a basic configuration of the printer / scanner multifunction device PS.
This printer / scanner multi-function machine PS is a USB 1. It corresponds to X and has functions as a PCL (Printer Control Language) printer corresponding to page description, a Windows (registered trademark) dedicated GDI (Graphic Device Interface) printer, and a TWAIN compatible scanner.
The multi-function device PS includes an MPU 11 that forms control means for the printer / scanner multi-function device PS by software processing, a USB controller 12 having a USB connector 12a, a display unit 13 having an LCD panel, and a serial interface. 14 and a ROM 18 that stores a control program for the printer / scanner multifunction device PS and a RAM 19 that stores setting data, variables, and image data in a rewritable manner through a local bus. An operation unit 15 formed by buttons and the like, a printer unit 16 that prints on recording paper, and a scanner unit 17 that reads image data of a document are each provided with a control microcomputer and are connected by a serial bus.
The USB connector 12a includes a Vbus terminal for USB bus power, a D + terminal and a D- terminal for balanced transfer signals, and a GND terminal for ground, and is compatible with plug and play.
In the following description, the USB 1... Between the printer / scanner multifunction device PS and the host workstation PC will be described. A connection using X (1.0 or 1.1) will be described as an example.

FIG. 2 is a diagram for explaining a system including the multifunction peripheral of the present invention connected to a host computer by a USB cable.
In the figure, a workstation PC is connected to a keyboard KB, a mouse M, a speaker SP, and a printer / scanner multifunction device PS via a hub H via a USB cable and functions as a host. USB1. X is a packet transfer of 1 ms per frame, and the keyboard KB responds to polling from the host and transfers data at a maximum speed of 12 Mb / s.

FIG. 3 conceptually shows the form of packet transfer used in the present invention.
In the figure, the SOF packet at the head of the first and second frames indicates a frame start packet issued by the host every 1 ms. Audio for the first and second frames is data transfer for the speaker SP, Key for the first frame is data transfer for the keyboard KB, and Printer for the first frame is data transfer for the printer / scanner multifunction device PS. In the second frame, Mouse represents data transfer for the mouse M.
As will be described later, the transfer is mainly used at the time of setup, and a control transfer composed of three stages and the following three types of data transfer are prepared. The three types of data transfer are used when there is a small amount of data, such as keyboard KB, but it is necessary to transfer data in real time. Interrupt transfer consisting of three packets of token, data, and handshake, and printer / scanner Used when a large amount of data is required, such as a multi-function device PS, but a large amount of data is required. Bulk transfer consisting of 3 packets of token, data, handshake, speaker SP, etc. This is an isochronous transfer composed of two packets of token and data, which is used when a rate needs to be secured and the transfer rate and transfer time are guaranteed but the error is not guaranteed.
Thus, USB1. In X, data is transferred in units of packets, but a plurality of packets constitute a transaction, and several transactions gather to constitute one transfer. Next, the configuration of the packet will be described.

FIG. 4 is a diagram illustrating the structure of four types of packets corresponding to FIG.
In the figure, an SOF packet is a frame start packet issued by the host every 1 ms as described above, a token packet is a packet issued by the host at the start of a transaction, a data packet is a packet used at the time of transfer, a handshake packet is an interrupt transfer or A packet used in a transaction for performing flow control such as bulk transfer. The ADDR of the token packet represents an address uniquely assigned by the host to each device such as a keyboard KB connected to the host via a USB cable, and the ENDP forms a device interface for each of these devices. Identifying the endpoint DATA in the data packet is bit string data and has a size of 0 to 1023 bytes depending on the type of transfer.
Each device has a USB1. In the case of the X standard, it can have a maximum of 16 endpoints EP0 to EP15, and these endpoints are mounted on the USB controller 12 in the case of a printer / scanner multifunction device PS, for example.
Here, the endpoint resource that is actually mounted depends on the model of the USB controller, and the model that mounts a large number of endpoints has a higher cost.
The end point EP0 is determined to be used for control transfer in the conventional USB protocol, and is mounted on any USB controller. Each of these end points EP0 to EP15 is provided with a FIFO buffer, and a pipe is formed with the host so that data can be independently transferred to and from the host.
Next, a device configuration by plug and play at the time of device setup will be described. The device is USB1. It has a state (state) for x, and transitions between the states according to plug and play processing.

FIG. 5 is a diagram showing the state transition of the USB device device. With reference to FIGS. 5 and 1, and 2, the device configuration of the printer / scanner multifunction device PS according to the embodiment of the present invention will be described. To do.
Here, it is assumed that the printer unit 16 of the printer / scanner multifunction device PS has been set in advance so as to operate as a GDI printer unit by an operation input of a setting option from the operation unit 15.
First, when the power of the printer / scanner multifunction device PS is turned on, the MPU 11 initializes the USB controller 12 by software processing and sets predetermined values in the respective registers. As a result, the USB controller 12 is set in the power-on state and waits in the hold state (S101 to S102) until it is connected to the hub H.
If the printer / scanner multifunction device PS is connected to the hub H as shown in FIG. 2, the hub H detects the printer / scanner multifunction device PS and reports it to the USB protocol stack of the host.
In response to this, the USB protocol stack sends an instruction to the hub H to open the port to which the printer / scanner multifunction device PS of the hub H is connected. At this time, the printer / scanner multifunction device PS uses the USB controller. The MPU 11 is notified of the detection of the pull-up voltage at the D + terminal of the 12 SB connectors 12a.
In response to this, the MPU 11 changes the USB controller 12 to the default state (S103), and the USB1. In accordance with the X standard, the reception from the host is waited at the default address 0 (S104). The USB protocol stack is USB1. In accordance with the X standard, control transfer is started, a GET_DESCRIPTOR standard device request is transmitted to the device having the default address 0, and a device descriptor specifying the device is requested. Upon receiving this request from the USB controller 12, the MPU 11 causes the USB controller 12 to respond with a predetermined device descriptor.

When the USB protocol stack acquires the device descriptor, it assigns a unique address in the system to the printer / scanner multifunction device PS.
While sending a SET_ADDRESS standard device request to address 0, a predetermined device driver is loaded based on the VID and PID for specifying the printer / scanner multifunction device PS in the obtained device descriptor, and the loaded device Transfer control to the driver. The MPU 11 that has received the notification from the USB controller 12 that has received the SET_ADDRESS standard device request causes the USB controller 12 to set the address specified in the SET_ADDRESS standard device request, and transitions the USB controller 12 to the address state (S105).
The device driver to which control is transferred from the USB protocol stack acquires each descriptor for device configuration from the printer / scanner multifunction device PS, and transmits a SET_CONFIGURATION standard device request. Upon receiving the notification from the USB controller 12 that has received the SET_CONFIGURATION standard device request, the MPU 11 causes the USB controller 12 to configure a predetermined device interface, and transitions to the configuration state (S107).
In each of the above states, the USB controller 12 automatically transitions to the hold state (S102, S104, S106, S108) as the standby time elapses, and returns to the original state in response to a transfer or a command from the MPU 11. It has become.

Such plug-and-play device configuration is performed by control transfer, and the end point EP0 is always used for a standard device request.
Therefore, the endpoint EP0 is capable of 64-byte fixed length bidirectional transfer (host ← → device). The endpoints EP1 to EP15 can perform unidirectional transfer (host → device or host ← device) of 0 to 1023 bytes. However, the endpoints EP1 to EP15 cannot be used in the device configuration. .

The present invention is characterized in the configuration of the device interface as described above, and the control means built in the digital multifunction peripheral is the control transfer in the printer / scanner multifunction peripheral PS of the embodiment. The bidirectional endpoint EP0, which has been used only for the purpose, is used for data transfer to both the printer unit 16 and the scanner unit 17 after the device interface is configured.
As a result, in the printer / scanner multifunction device PS, the use of the endpoint resource is suppressed, so that the USB controller 12 can adopt a model with a small number of endpoint resources, and the cost can also be suppressed.
A device interface constructed in accordance with the present invention will now be described with respect to FIG. 1A.
FIG. 1A conceptually shows the basic configuration of the device interface of the GDI printer unit and the device interface of the TWAIN scanner unit in the printer / scanner multifunction device PS.
In the figure, in addition to the standard device request in the above-described plug and play device configuration, the control response of the GDI printer unit and the control of the TWAIN scanner unit are assigned to the end point EP0. In the device interface 0 of the GDI printer unit, GDI printer control and print data transfer are assigned to EP1 as bulk transfer from the host to the device. In the device interface 1 of the TWAIN scanner unit, the control response of the TWAIN scanner unit and transfer of read data are assigned to EP2 as bulk transfer from the device to the host.

As described above, in the printer / scanner multi-function apparatus PS according to the embodiment of the present invention, the end point EP0 is assigned to the control response of the GDI printer unit and the control of the TWAIN scanner unit to configure the device, thereby using the end point resource. It is possible to use the low-cost USB controller 12 with a small amount of endpoint resources (suppressed (only EP1 and EP2 are used)).
Of course, it is possible to use the printer unit of the printer / scanner multifunction device PS according to the embodiment of the present invention as the PCL printer unit, and the same device configuration by plug and play as described above is performed.
In the above embodiment, the USB 1. Although the printer / scanner multifunction device PS conforming to the X standard has been described, it is also possible to adapt the present invention to the USB 2 standard. Further, the present invention is not limited to a printer / scanner multifunction device, and the same technical idea can be applied to other multifunction devices including a keyboard / mouse multifunction device.

1 is a block diagram illustrating a basic configuration of a printer / scanner multifunction machine according to an embodiment of the present invention. FIG. 2 is a conceptual diagram illustrating a basic configuration of a device interface of a printer / scanner multifunction peripheral. FIG. 2 is a diagram illustrating systems connected to each other by a USB cable. It is a conceptual diagram explaining USB packet transfer. It is drawing which shows the structure of a USB packet. It is drawing which shows the state transition at the time of the setup of a device.

Explanation of symbols

11 MPU
12 USB controller 12a USB connector 16 Printer unit 17 Scanner unit 18 ROM
EP0 to EP2 endpoint

Claims (3)

In a USB-compatible digital multifunction peripheral that operates as a plurality of types of peripheral devices such as a printer and a scanner through a host computer and a USB interface.
In order to execute the functions of the plurality of types of peripheral devices equipped with a plurality of endpoints, the endpoints are provided with data for each function so as to send and receive data according to a predetermined communication protocol with the host computer. A USB controller that allocates to transfer and configures the device interface;
Among the plurality of endpoints equipped in the USB controller, after the device interface is constructed, the bidirectional endpoint used for control transfer at the time of configuring the device interface is at least one of the plurality of types of peripheral devices. A USB compatible digital multi- function peripheral comprising control means for assigning data transfer for executing the function of one peripheral device . In claim 1,
After the device interface is configured, the control means corresponds to the transfer direction of the bidirectional endpoints for each of the data transferred to execute the functions of two peripheral devices among the plurality of types of peripheral devices. USB compatible digital multi-function peripherals that are assigned. In claim 2,
The control unit assigns the data to the bidirectional endpoints so that the transfer directions are opposite to each other among copy, printer, scanner, camera, facsimile transmission / reception image data, their commands, and response signals. USB compatible digital multi-function peripherals identified by one.

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