JP2001325049A - Interface device and output device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an output device having a simple constitution, capable of automatically setting an interface to be used, even in an output device, such as a printer equipped with a parallel port interface and a USB interface. SOLUTION: After a printer is allowed to stand by, either a parallel port interface 10 or a USB interface 20 which receives data at first is judged by a CPU 31, and the other interface is made invalid. Afterwards, only one interface is made valid, so that it is not necessary to realize cooperation between those interfaces, or to reinforce memory for temporarily storing data from the other interface. Thus, it is possible to automatically make appropriate use of the interfaces, whose specifications are different, using a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an interface device having a plurality of interfaces and an output device for outputting data.

[0002]

2. Description of the Related Art In recent years, a connection between an output device such as a printer and a host has been conventionally made using SCSI, RS-2, and the like.
32C, parallel interface (IEEE1284)
In addition, interfaces such as USB and IEEE1394 are also used. USB or IE
Interfaces such as EE1394 have excellent performance such as high versatility and high speed, and can replace conventional interfaces. On the other hand, personal computers on the host side support these interfaces. If not, you cannot connect. For this reason, it is desirable to provide a recording device in which a new interface becomes available in a state where it can be used for resources such as a conventional personal computer. Therefore, U
A printer provided with an interface of a new standard such as SB and an interface of a conventional standard such as a parallel interface is provided.

[0003]

In order to use an output device having a plurality of interfaces of different standards, for example, a printer having a parallel port interface and a USB interface, one of the devices must be used before using the printer. It is necessary for the user to select one interface or to configure the internal circuit and firmware of the printer so that all interfaces can be used.

If one of the parallel port interface and the USB interface is selected by a hardware switch or a software switch before using the printer, only the data supplied from the selected interface needs to be dealt with. Therefore, the load on both hardware and software (firmware) is small. However, it is cumbersome because the user must select an interface before using the printer.
If a personal computer is connected to an interface that has not been selected by mistake, no output is made. For this reason, a malfunction of the printer may be suspected. In such a case, the user and the maker need to spend extra time and effort to solve the problem.

It is also possible to configure so that data can be input from both the parallel port interface and the USB interface. Since any of the interfaces can be used at all times, the user can use the printer simply by connecting to an interface suitable for his or her environment without hesitation. However, the fact that both the parallel port interface and the USB interface can be used requires hardware and software to be configured to cope with the case where a host is connected to both, which increases the cost. For example, you need to provide buffers for each interface,
Furthermore, considering that the timing at which data to be printed is supplied to each interface overlaps, it is necessary to increase the memory so that print data can be temporarily stored. To reduce the memory capacity, a coordination or coordination between interfaces such as outputting a busy signal while data is being received from one interface to prevent data from being input from the other interface is required. Must be performed, and hardware and firmware that can execute the processing are required.

Therefore, in the present invention, without complicating firmware and hardware, on the other hand,
An object of the present invention is to provide an interface device capable of automatically selecting an interface and an output device such as a printer using the interface device. It is another object of the present invention to provide a low cost user-friendly output device that can use any of a plurality of interfaces without troublesome operations such as operating a switch.

[0007]

For this reason, according to the present invention, among a plurality of interfaces of different standards, after the interface is supplied with power and is ready to receive data from the interface, the interface that first receives the data By disabling the functions of other interfaces,
The interface that can receive data can be automatically selected. That is, the interface device of the present invention includes a plurality of interfaces having different standards capable of receiving data from the outside, and an interface other than the interface that first received the data after the data can be received from the plurality of interfaces. And a processing unit for disabling the function. Further, in the control method of the interface device of the present invention having a plurality of interfaces of different standards capable of receiving data from the outside,
After a state in which data can be received from a plurality of interfaces, a step of disabling functions of interfaces other than the interface that first received the data is provided.

In the interface device and the control method according to the present invention, after the power is turned on and the data can be received, the data can be received from a plurality of interfaces after the data is first received. However, after that, one of multiple interfaces
Only one is enabled, the other interfaces are masked and disabled and are invisible to the outside world (host). Then, that state is maintained while the state in which data can be received continues, and only the selected interface can be used. Therefore, the circuits and firmware that are actually operated only need to be compatible with one selected interface, and do not require complicated circuits and firmware that perform processing for arbitrating a plurality of interfaces. Also, since the interface that did not receive data first is masked, even if data is sent after connecting to that interface later, it is not received, and the host can determine that the interface cannot be used.

When accepting data for the first time, it is necessary to deal with a plurality of interfaces. However, after disabling other interfaces, it is possible to request data used for printing or the like again from an effective interface. There is no need for a configuration and processing such as providing a buffer for each of a plurality of interfaces to store data for use. Therefore, the configuration for receiving data from a plurality of interfaces is very simple and good.

On the other hand, in the interface device of the present invention, the interface to which data is first input is automatically selected, so that the user need not select an interface to be used in advance. Therefore, the trouble of selecting an interface in advance can be omitted.

[0011] Therefore, the interface device of the present invention and the output device for performing output based on the data received from these interfaces can provide an easy-to-use output device at low cost. Further, in the output device of the present invention, it is possible to reliably record data on a recording paper or a medium such as a magnetic disk by using any of the prepared interfaces, or to output the data to a screen in the case of a projector. Therefore, it is possible to prevent a trouble that data is not output by mistake in selecting an interface.

As described above, in the present invention, among the peripheral devices connected by using a personal computer or the like as a host, the interface device of the output device which performs processing such as recording data on a recording medium is connected first. Since data is received from a host or the like, an interface is automatically selected based on the process, and only that interface can be maintained in an active state. Therefore, hardware and software for enabling all of the plurality of interfaces to be used at the same time are unnecessary, while the interface to be used can be automatically set.

With an interface such as a USB that performs main processing by software, the interface can be masked by software processing such as masking an interrupt when data is transmitted, and can be handled by firmware. On the other hand, in an interface in which hardware is established, such as a parallel port interface, it is necessary to change the hardware and mask the interface, which requires labor and cost in circuit design and the like. Therefore, for an interface in which hardware such as a parallel port interface is established, a signal supplied from the interface connector to the interface control circuit is provided between the interface control circuit for controlling the interface and the interface connector for connecting the cable. It is desirable to provide a mask circuit for masking the data by a control signal from the processing unit.

For example, when one of a plurality of interfaces is a parallel port interface, in addition to a parallel port control circuit for controlling the parallel port interface and a parallel port connector, the parallel port connector supplies the parallel port control circuit. By providing a mask circuit for masking a signal to be performed by a control signal from the processing unit, the mask circuit can mask a signal input to the interface control circuit. For this reason, the interface can be masked without changing the parallel port control circuit itself that controls the parallel port interface.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a printer according to the present invention. Printer 5 of this example
Is provided with a parallel port interface (IEEE1284) 10 standardized by IEEE and a USB interface 20 according to one standard of a serial bus, USB (Universal Serial Bus), as an interface with a personal computer serving as a host. . Further, in order to process data input from these interfaces 10 and 20 and output the data at the printing mechanism 36,
A CPU 31 for controlling the overall processing of the printer 5, and a ROM 32 for storing programs for the CPU 31;
And a RAM 3 serving as a temporary storage area for image data and the like.
3 are connected by an internal bus 34. The control unit 6 of the printer 6 is formed by the CPU 31, the ROM 32, the RAM 33, the internal bus 34, and the following control devices or circuits connected to the internal bus 34. The control unit 6 is mounted on a control board and supplied. Alternatively, the whole or a part is supplied as a chip in the form of an ASIC.

Data input from the host via these interfaces 10 or 20 is processed by the logic control unit of the control unit 6 functioning as an interface device having these interfaces, the CPU 31, and the like, and is stored in the RAM 33. The data processed in a printable state is further supplied to a printing mechanism 36 via a printer interface 35, and the printing mechanism 3
6 is printed out on a recording sheet by a print engine, a paper feeding mechanism, or the like included in the printer.

The control unit 6 includes connectors 11 and 21 for connecting cables, and control logic units 12 and 22 for controlling data transfer and the like, respectively. The data output from the parallel port control logic 12 of the parallel port interface 10 is further supplied to a data processing unit 8 having a function for decompressing or decompressing the data implemented by a circuit or hardwire logic. As a result, the processed data such as decompression
It is temporarily stored in the AM 33 or further processed in the CPU 31. On the other hand, in the USB interface 20, data processing functions such as reconstructing packetized data and returning an acknowledgment to received data are realized by software. Therefore, the data output from the USB control logic unit 22 is processed by the CPU 31, and a response to the received data to the host is also performed by the CPU 31.

In the printer 5 of the present embodiment, a mask circuit 13 is further inserted between the connector 11 of the parallel port interface 10 and the control logic section 12, and a signal from the connector 11 is transmitted by a mask signal φm from the CPU 31. All can be masked at a high level. Therefore, the parallel port interface 10 can be disabled by a signal from the CPU 31. On the other hand, in the USB interface 20, a response of data transmission / reception is performed by the CPU 31.
Therefore, the interrupt for transmitting and receiving data is masked by the firmware, so that the USB interface 2 can be used.
0 can be invalidated by the CPU 31.

FIG. 2 is a block diagram showing a control system for enabling or disabling the interfaces 10 and 20. In this example, the USB interface control logic unit 22 and the parallel port interface control logic unit 12 are connected to one ASIC 9
It is provided by. Further, the ASIC 9 of this example includes a mask circuit 13 that can mask all signals supplied to the parallel port control logic unit 12,
A switching register 15 capable of storing a control signal φm of the mask circuit 13 is mounted. The mask circuit 13 of the present embodiment is constituted by an OR gate 13a which takes the logical sum of each of the signals φi from the host and the control signal φm. When the control signal φm becomes high, the mask circuit 1
3 are all high level.

In this example, the CPU 31 functions as a processing unit for determining an interface that has received data first.
When it is determined that 0 is invalidated, and the switching register 14 is set to output the high-level control signal φm, all the signals φi from the host are masked to the high level. Therefore, the parallel port control logic unit 12 does not respond to the signal φi from the host, and the parallel port interface becomes invalid. Also, AS
Since the switching register 14 is prepared in the IC 9, the CPU 9
The controller 31 can invalidate the parallel port interface 10 once the processing for setting the switching register 14 is performed. For this reason, the load on the CPU for selecting an interface can be minimized.

To invalidate the parallel port interface 10, the parallel port control logic unit 1
Of course, it is also possible to design a circuit in which a signal from the CPU 31 is fetched by changing the circuit constituting the circuit 2 and an acknowledgment signal is not output. However, the existing parallel port control logic circuit needs to be modified, and a step of redesigning the conventional established circuit and further verifying the circuit is required. Therefore, labor and labor costs are incurred.
On the other hand, in the printer 5 of the present embodiment, all signals supplied to the parallel port control logic circuit 12 are masked by providing the mask circuit 13. For this reason, the function can be invalidated without modifying the parallel port control logic circuit 12. Furthermore, the control logic circuit 1
By masking all signals input to 2,
It is not necessary to check the operation inside the control logic circuit 12. Therefore, it is possible to minimize the period and man-hour required for design and verification, and to develop and supply an ASIC 9 that can securely disable the parallel port control circuit 12 at low cost in a short period. Can be.

FIG. 3 shows a process for setting an interface for receiving data in the printer 5 of the present embodiment. First, when the standby mode is set in step 51, the process waits for input of the first data in step 52. The standby state is a state in which the printer 5 can receive data. In a printer having a manual power switch, the power switch is turned on. In a printer that has no manual power switch and is supplied with power when a plug is inserted into a household outlet, the state in which the plug is inserted is standby. In the printer 5 of the present embodiment, after the power is turned off to the standby state, data can be received from both the parallel port interface 10 and the USB interface 20. When data is received from one of the interfaces in step 52, the CPU 31 operating based on the firmware determines the interface that received the data in step 53.

In step 53, the USB interface 2
If data is received from 0, the CPU proceeds to step 54.
31 sets the switching register 14 of the ASIC 9 so that a high-level signal φm is output. As a result, even if a parallel cable is connected to the parallel connector 11, all signals supplied to the parallel port control logic 12 by the mask circuit 13 are masked to a high level. Therefore, in the printer 5 of this example, the parallel port interface 10 is in an invalid state, and data cannot be sent from an external host.

On the other hand, when data is received not from USB but from the parallel port interface 10 in step 53, the CPU 31 operating based on the firmware
The setting is made so as to mask the interrupt signal supplied to the PU 31. Therefore, even if a cable is connected to the USB interface 20, the printer 5 does not respond, and the USB interface 20 is disabled in the printer 5 of the present embodiment.

As described above, only one of the parallel port interface 10 or the USB interface 20 which receives data first becomes valid, and after the other interface becomes invalid, at step 56, data is received first. Receives data for printing from the interface. The received data is sent to the CPU based on the firmware.
The data is processed into a printable state by the function of the data processing unit 31 or the data processing unit 8, and is temporarily stored in the RAM 33. Further, the data is sent to the printing mechanism 36 and printed out on a recording sheet.

The state in which one interface is enabled in steps 54 and 55 and the other interface is disabled is maintained as long as the standby state is established in step 57. That is, the interface disabled in step 54 or 55 remains disabled until it is powered off by any means and is no longer in standby. Therefore, in the printer 5 according to the present embodiment, if the interface that first receives data after the power is turned off and enters the standby mode is the parallel port interface 10, only the parallel port interface remains valid until the power is turned off. Conversely, if the interface that first received the data is the USB interface 20, only the USB interface is valid until the power is turned off.

Therefore, once data is received, the printer 5 of the present embodiment functions similarly to a printer having only one of the parallel port interface 10 and the USB interface 20. Therefore, the printer 5 can be controlled with almost the same firmware as a USB-dedicated printer or a parallel port-dedicated printer, and it is not necessary to greatly increase the firmware or increase the temporary storage memory.

In the process of receiving data for the first time after the standby mode (step 52), it is not necessary to analyze a print command included in the received data or print the received data. It is only necessary to be able to recognize that data has been received from either one of the interfaces 10 or 20.
It is also possible to request the data for printing again after enabling one of the interfaces. Therefore, in the printer 5 of this example, both interfaces 10 and 20 can be used immediately after the standby, but a function capable of interpreting a command or data for printing is not required. Can be dealt with without increasing

On the other hand, both interfaces 10 and 20 are effective immediately after the standby state, and either one can be automatically selected simply by inserting a cable into the connector 11 or 21 and sending data. Therefore, it is not necessary to select the parallel port interface 10 or the USB interface 20 in advance using the local operation panel of the printer 5 or the like, and an interface suitable for the user's use environment is automatically selected. Therefore, the trouble of selecting an interface can be omitted,
Since there is no mistake in the interface, data can be reliably sent to the printer 5 and printed simply by connecting the cable to the corresponding connector 11 or 21. For this reason, the printer 5 of this example is easy to use and user-friendly. As described above, such a function can be realized by the same hardware (of course, the interface and its related components are added) and firmware of a printer having only one of the interfaces. A good printer at low cost.

Further, printing can be performed reliably only by connecting a cable to the connector 11 or 21. For this reason, it is possible to prevent the trouble that the printout cannot be performed even though the cable is connected, and the user is also friendly in this respect. Further, it is possible to reduce troubles that the printer maker needs to deal with.

Further, the parallel port interface 1
In the case of 0, since the signal is masked by the mask circuit 13, the control logic circuit 12
It is possible to use an existing circuit as it is.
Therefore, costs for designing and manufacturing can be further reduced, and a user-friendly printer can be provided at low cost.

In the above description, the parallel port interface (Centronics interface or IEEE
1284) and a printer having a USB interface, the present invention is described as an example. However, the type of interface is not limited to these, and RS-232C, SC
The present invention can be applied to a printer having a plurality of interfaces having different standards such as SI and IEEE1394. Further, the present invention can be applied even if three or more interfaces are prepared, and if data is received from any one, all other interfaces may be invalidated.

In this embodiment, the parallel interface logic 12, the USB control logic 22,
Although the mask circuit 13 and the ASIC 9 are provided by one ASIC 9, the range of integration is not limited to this, and each control logic can be realized by a different chip. It is also possible to integrate the control circuit (interface circuit) 6 into one chip, including the functions described above. Further, in this example, the CPU 31 determines whether the first data is received by any of the parallel port interface 10 or the USB interface 20, but the ASIC 9 has a processing unit that performs such determination. A functioning circuit can be incorporated, and the ASIC 9 can be provided as an interface device according to the present invention.

Further, the output device to which the present invention can be applied is not limited to a printer that outputs data to recording paper. A recording device such as a magnetic disk device that outputs data to a storage medium such as a magnetic disk, or a display device that displays data on a display such as an LCD may be used. When a device having these output functions is connected to a host, first, the host sends data to the device. For this reason, similar to the printer described above,
By recognizing the interface that first received the data output from the host, it is possible to set an optimal interface for the connection environment.

[0035]

As described above, in the interface device and the output device according to the present invention, a plurality of interfaces having different standards are prepared, and the interface other than the interface which received data first among them is invalidated. Therefore, it operates as an interface device having a single interface or an output device thereafter. Therefore, it is possible to prevent hardware such as control software and memory from becoming complicated, and to provide an interface device and an output device that can use a plurality of interfaces at low cost.

Further, since an interface to be used among a plurality of interfaces is automatically set, the trouble of manually selecting the interface in advance can be omitted, and troubles such as an incorrect setting of the interface and the inability to use the output device can be obtained. Can also be prevented. Therefore, according to the present invention, a user-friendly device can be provided at a low cost with an output device such as a printer having a plurality of types of different interfaces.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a printer according to the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of an ASIC in which a parallel port interface logic unit and a USB interface logic unit are configured in the printer illustrated in FIG. 1;

FIG. 3 is a flowchart showing an outline of processing for setting an interface in the printer shown in FIG. 1;

[Description of Signs] 5 Printer 6 Control Unit (Interface Device) 8 Data Processing Unit 10 Parallel Port Interface 11 Connector 12 Parallel Port Interface Logic Circuit 20 USB Interface 21 Connector 22 USB Interface Logic 30 Image Memory, 31 CPU, 32 RO
M, 33 RAM 36 printing mechanism

Claims (7)

[Claims] 1. A plurality of interfaces having different standards capable of receiving data from the outside, and functions of the interfaces other than the interface that first received the data after the data can be received from the plurality of interfaces. An interface device having a processing unit for invalidating the function. 2. The apparatus according to claim 1, wherein at least one of the plurality of interfaces includes an interface control circuit for controlling the interface, an interface connector, and a signal supplied from the interface connector to the interface control circuit. And a mask circuit for masking with a control signal from a unit. 3. The method of claim 1, wherein one of the plurality of interfaces is a parallel port interface.
An interface having a parallel port control circuit for controlling the parallel port interface, a parallel port connector, and a mask circuit for masking a signal supplied from the parallel port connector to the parallel port control circuit with a control signal from the processing unit. apparatus. 4. An output device comprising: the interface device according to claim 1; and an output unit that performs output based on data received from any of these interfaces. 5. The output device according to claim 4, wherein the output unit performs recording on a recording medium based on data received from any of the interfaces. 6. A method for controlling an interface device having a plurality of interfaces of different standards capable of receiving data from the outside, wherein the data is received first after data can be received from the plurality of interfaces. A method of controlling an interface device, comprising a step of invalidating a function of the interface other than the interface. 7. A control method of an output device for outputting based on data received from any of a plurality of interfaces having different standards, wherein the data is first received after data can be received from the plurality of interfaces. A method for controlling an output device, comprising: disabling a function of the interface other than the interface that has received the command.