JPH11195110A - Frame memory device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a waiting time in a host device and to improve the working rate of the host device by informing the fact to the host device that access can not be accepted when an input device start the access and that the access can be accepted when the access is finished. SOLUTION: A frame memory 3 stores picture data inputted through a scanner I/F 2. A register group 6 is provided with a using information informing part 7 consisting of a using period register, a using period counter etc. At the time of receiving a heating signal on the line of a read picture, the part 7 outputs a readable start interruption signal to a host device. The using period counter counts down the number of usable pixels stored in the using period register as a trigger by a pixel clock. When the value becomes zero, the using period counter outputs a readable end interruption signal showing that the picture data can no longer be read out to the host device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame memory device provided between a host device such as a computer device and a workstation device and an input / output device such as a scanner device and a printer device. To improve the operation rate of the host device.

[0002]

2. Description of the Related Art In a frame memory device provided between a host device such as a computer device and a workstation device and an input / output device such as a scanner device and a printer device, accesses from the host device and the input / output device are simultaneously accepted. Then, the image data will collide. Therefore, the frame memory device waits for an access from the host device while the scanner and the printer device are accessing the frame memory.

[0003]

However, if the input / output devices such as the scanner and the printer are accessing the frame memory only while waiting for the access from the host device, the host device cannot be used. It waits until the access from is completed, and cannot proceed with other processing.

The present invention has been made to solve such a disadvantage, and has as its object to increase the operating rate of a host device.

[0005]

According to the frame memory device of the present invention, when the frame memory is accessed from an input device such as a scanner device, the frame memory device notifies the host device that the access is not accepted, The image data read from the device is temporarily stored in a frame memory to prevent the host device such as a computer device from accessing when the input device is accessing the host device, thereby preventing the host device from going into a waiting state. Enable the host device to perform other processing.

When the access from the input device is completed, the host device is notified that the access is accepted, and the image data stored in the frame memory is output to the host device in response to a request from the host device.

When another frame memory device receives an access from an output device such as a printer device, it notifies the host device that the access cannot be received.
The image data stored in the frame memory is output to an output device, and when the output device is accessing, the host device such as a computer device does not access and the host device is prevented from entering a waiting state. Enable the host device to perform other processing.

When the access from the output device is completed, the host device is notified that the access is accepted, and image data is input from the host device in response to a request from the host device.

Further, information on a period during which the host device can access the frame memory is output,
The host device can suspend access to the frame memory.

Further, when the access of the host device can be accepted, the host device is interrupted and notified to that effect, and the host device determines whether or not the access can be accepted at all times. Eliminate the need to check.

Further, immediately before the host device cannot accept the access, the host device is interrupted to notify the host device that the access cannot be accepted, and the host device access is accepted again. Until the host device can perform other processes, the host device can perform other processes.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A frame memory device according to the present invention is a frame memory device provided between a host device such as a computer device and a workstation device and an input / output device such as a scanner device and a printer device. Therefore, the operating rate of the host device is improved by reducing the waiting time.

The frame memory device of the present invention includes, for example, a host interface (hereinafter, referred to as "host I / F"), a scanner interface (hereinafter, referred to as "scanner I / F"), a frame memory, an address generator, and an address decoder. And a register group.

The host I / F transmits and receives data and control signals to and from the host device. The scanner I / F transmits and receives data and control signals to and from the scanner device. The frame memory stores image data read by the scanner device. The address generator generates an address of the frame memory based on a pixel clock signal, a GATE signal, a line synchronization signal, and the like from the scanner device.
The address decoder receives an address signal from the host device, an address signal from the address generator, and the like, and outputs a select signal for a frame memory or the like.

The register group includes, for example, a main scanning direction size register and a main scanning direction counter. The main scanning direction size register stores in advance the number of effective pixels in the main scanning direction of image data from the scanner device. The main scanning direction counter loads the number of effective pixels in the main scanning direction from the main scanning direction size register when image data from the scanner device becomes valid, counts down the number of effective pixels based on a pixel clock, and counts the value. Becomes zero, the host device outputs a readable start interrupt signal indicating that the host device has become readable.

Further, the register group includes a use information notifying section including an available period register and an available period counter. The usable period register stores in advance the number of usable pixels of the host device (the number of invalid image pixels in the main scanning direction of image data from the scanner device). When the value of the main scanning direction counter becomes zero, the use period counter loads the value stored in the use period register, counts down this value with the pixel clock, and when the value becomes zero, the host device cannot read out. And outputs a readable end interrupt signal indicating the above. With this, the use information notifying unit notifies the host device that the access cannot be accepted when the input device accesses the frame memory, and notifies the host device when the input device ends the access to the frame memory. The user can be notified that access is accepted. As described above, when the access from the input device is received, the host device is notified that the access is not accepted, so that the host device does not access when the input device is accessing,
This prevents the host device from waiting for a response from the frame memory device and being unable to perform other processing.

Further, even when the image data is being fetched from the scanner device, if the data is outside the valid data and the frame memory is not accessed, the image data is fetched from the frame memory to the host device. Therefore, data can be captured at high speed.

Also, instead of providing the frame memory device between the scanner device and the host device, it may be provided between the printer device and the host device. When the frame memory device is installed between the printer device and the host device, access from the host device occurs while the printer device accesses the frame memory as in the case where it is installed between the scanner device and the host device. Don't do it.

[0019]

FIG. 1 is a connection diagram of a frame memory device 10 according to an embodiment of the present invention. 1, the frame memory device 10 includes, for example, a host I / F 1 and a scanner I / F 1.
F2, a frame memory 3, an address generator 4, an address decoder 5, and a register group 6. Host I
/ F1 transmits and receives data and control signals to and from a host device (not shown). The scanner I / F 2 transmits and receives data and control signals to and from a scanner device (not shown). The frame memory 3 is read by the scanner device,
The image data input via the scanner I / F2 is stored. The address generator 4 generates an address of the frame memory 3 or the register group 6 based on a pixel clock signal, a GATE signal, a line synchronization signal, and the like from the scanner device. The address decoder 5 receives an address signal from the host device, an address signal from the address generator 4 and the like, and outputs a select signal for the frame memory 3 and the like.

The register group 6 includes a plurality of registers and counters such as a main scanning direction size register 61 and a main scanning direction counter 62 as shown in FIG. 2, and stores setting information and status information. In the main scanning direction size register 61, a value corresponding to the maximum number of pixels for one line in the main scanning direction can be set, and the number of effective pixels in the main scanning direction of image data from the scanner device is stored in advance by setting from the host device. I do. The main scanning direction counter 62 allows the host device to read the value.
When the image data from the scanner device becomes valid, the number of effective pixels in the main scanning direction is loaded from the main scanning direction size register 61, and the number of effective pixels is counted down based on a pixel clock. A readable start interrupt signal indicating that the device has become readable is output.

The register group 6 includes a use information notifying section 7 including a use period register 71, a use period counter 72, and the like. The use period register 71 stores the main scan direction 1
A value corresponding to the maximum number of pixels for a line can be set, and the number of usable pixels of the host device (the number of pixels of an invalid image in the main scanning direction of image data from the scanner device) is stored in advance by setting from the host device. I do. Usage period counter 72
Is designed so that the host device can read the value. When the value of the main scanning direction counter 62 becomes zero, the value stored in the use period register 71 is loaded, and this value is counted down by the pixel clock. When the value becomes zero, a readable end interrupt signal indicating that image data cannot be read is output to the host device.

The output timing of the readable start interrupt signal and the readable end interrupt signal will be described with reference to the signal charts of FIGS. Here, in FIG. 3, the number of pixels for the unusable time of the frame memory 3 which depends on hardware and software is represented as zero. Therefore, the number of image clocks LM for one line = the number G of clocks for valid images + the number M of clocks for invalid images. In FIG. 4, the readable start interrupt signal and the readable end interrupt signal are represented by active high.

When a head signal of a line of a read image is received, an offset register (not shown) loads an offset value in the main scanning direction (the number of clocks C for the offset) into an offset counter (not shown), and down-counting starts. . When the value of the offset counter becomes zero, the main scanning direction size register 61 loads the number of effective pixels G in the main scanning direction into the main scanning direction counter 62 by using this as a trigger, and
The main scanning direction counter 62 starts counting down the effective pixel number G.

When the value of the main scanning direction counter 62 becomes zero (FIG. 4D), the main scanning direction counter 62 outputs a readable start interrupt signal (FIG. 4E). Further, using the readable start interrupt signal as a trigger, the use period counter 72 loads the number of usable pixels (the number M of pixels of an invalid image in the main scanning direction of image data from the scanner device) stored in the use period register 71. Then, this value is counted down by the pixel clock. When the value of the use period counter 72 becomes zero (FIG. 4H), the use period counter 72 outputs a readable end interrupt signal indicating that image data cannot be read to the host device (FIG. 4K).

As described above, when the frame memory 3 receives the access from the input device such as the scanner device, the host device is notified to the host device that the access is not accepted by using the readable interrupt signal. When the device is accessing, the host device such as a computer device does not need to access the frame memory 3, and the host device can perform other processing while preventing the host device from entering a waiting state.

Further, even when the image data is being fetched from the scanner device, if the data is outside the valid data and the access to the frame memory 3 is not performed (the area shown in FIG. 3M), the frame memory 3 Since the image data can be fetched from the host device to the host device, the host device can reduce the waiting time and can fetch the data at high speed.

Next, the frame memory device 1 having the above configuration will be described.
An example of the data read operation of the host device with respect to 0 is
This will be described with reference to the flowchart of FIG.

In the host device, first, the number of pixel clocks between line synchronizing signals (this value is a known value fixed for each scanner device) and the number of pixel clocks in the image portion (the number of clocks in the effective image portion) are based on the number of pixel clocks. First, the number of pixel clocks other than the image (the number of clocks for the invalid image) is obtained (step S).
1).

The number of pixels that cannot be used in the frame memory 3 depending on hardware and software is subtracted from the number of pixel clocks other than the image to obtain the number of usable pixels of the host (step S2). The host device stores the number of clocks of the effective image portion, the calculated number of usable pixels of the host, and the like in the main scanning direction size register 61 and the use period register 71.
To perform initialization (step S3).

Here, the scanner device reads an image as necessary, and the frame memory device 10 sends a readable start interrupt signal or a readable end interrupt signal to the host device according to the operation of the scanner device. When the host device receives the readable start interrupt signal, it sets a readable flag, and when the host device receives the readable end interrupt signal, it lowers the readable flag.

At the image data read request timing (step S4), the host device checks, for example, whether the value of a read counter (not shown) has become zero, and determines whether the scanner device has completed its operation. Check whether or not. When the operation of the scanner device has been completed, the host device reads image data from the frame memory 3 (steps S5 and S6).

If the operation of the scanner device has not been completed (step S5), the host device checks the readable flag (step S7). If the readable flag is down, the host device performs other processing without reading the image data because the scanner device accesses the frame memory 3. As described above, since the host device does not start reading image data when the scanner device is accessing the frame memory 3, the host device may be locked due to waiting for a response from the frame memory device 10. Can be prevented, and the processing efficiency of the host device can be improved.

When the readable flag is set, it means that the scanner is in operation but is a portion other than the effective image portion, and the frame memory 3 has not been accessed. From 72, a readable period is read (step S8), and pixels corresponding to that period are read (step S9). As described above, even when the scanner device is in the image reading operation, the host device can read the image data when the frame memory 3 is not accessed, so that the operation waiting time of the scanner device is reduced. As a result, the efficiency of image data reading processing of the host device can be improved.

In the above embodiment, the frame memory device 10 is provided between the host device and the scanner device. However, the frame memory device 10 is provided between the host device and an output device such as a printer device (not shown). When the output device accesses the frame memory 3 as described above, the host device is notified that the access is not accepted, and when the output device ends the access to the frame memory 3, the host device is notified. 6. Notify that access is accepted and Information about a period during which the host device can access the frame memory 3 may be output.

[0035]

As described above, according to the present invention, when the frame memory receives an access from an input device such as a scanner device, it notifies the host device that the access cannot be received, and the input device accesses the frame device. In this case, the host device such as a computer device does not access the frame memory, so that the host device can be prevented from entering a waiting state and the host device can perform other processing. .

When an access is received from an output device such as a printer device, the host device is notified that the access is not accepted, and when the output device is accessing, the host device such as a computer device is notified. Since access is prevented, the host device can be prevented from entering a waiting state, and the host device can perform other processing.

Further, since information on a period during which the host device can access the frame memory is output,
The host device is ready to suspend access to the frame memory.

Further, when an access from the host device can be accepted, the host device is notified of the fact by interrupting the host device. Therefore, the host device checks whether or not the access can be accepted at all times. The need can be eliminated.

Further, immediately before the host device cannot accept the access, the host device is notified that the host device cannot be accessed by interrupting the host device. Therefore, it is possible to accept the host device access again. Until it can, the host device can be allowed to perform other processing.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a frame memory device of the present invention.

FIG. 2 is a configuration diagram of a use information notification unit.

FIG. 3 is a signal chart explanatory diagram showing an effective image area and an invalid image area.

FIG. 4 is a signal chart showing a timing of a readable start signal and the like.

FIG. 5 is a flowchart illustrating an example of a data reading operation of the host device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Host I / F 2 Scanner I / F 3 Frame memory 4 Address generator 5 Address decoder 6 Register group 61 Main scanning direction size register 62 Main scanning direction counter 7 Usage information notification section 71 Usage period register 72 Usage period counter 10 Frame memory device

Claims (5)

[Claims] An image data read from an input device such as a scanner device is temporarily stored in a frame memory, and the image data stored in the frame memory is output to a host device in response to a request from a host device such as a computer device. In the frame memory device, when the input device starts accessing the frame memory, it notifies the host device that the access cannot be accepted, and when the input device finishes accessing the frame memory, it notifies the host device. A frame memory device for notifying that access is accepted. 2. A frame for temporarily storing image data from a host device such as a computer device in a frame memory and outputting the image data stored in the frame memory to an output device in response to a request from an output device such as a printer device. In the memory device, when the output device starts accessing the frame memory, the host device is notified that the access cannot be accepted, and when the output device ends the access to the frame memory, the host device is accessed. A frame memory device for notifying that a frame memory can be accepted. 3. The system according to claim 1, wherein the host device outputs information on a period during which the host device can access the frame memory.
Or the frame memory device according to 2. 4. The frame memory device according to claim 1, wherein when the access from the host device can be accepted, an interrupt is issued to the host device to notify the host device of the interruption. 5. The system according to claim 1, wherein immediately before the host device cannot receive the access, the host device is notified of the fact that the host device cannot receive the access by interrupting the host device. Frame memory device.