JP4298632B2 - Data input device - Google Patents

Description

  The present invention monitors video data of image equipment that handles data of image equipment represented by a digital copying machine in units of pages, and more specifically, a data input device used as a debugging / inspection jig for image equipment. It is about.

Conventionally, in a data input device that monitors streaming data or the like, in a data monitoring device that monitors data and sequentially stores the data in a semiconductor memory or the like, and overwrites the old data sequentially when the memory is full, In order to reduce the cost by reducing the memory capacity as much as possible, there is known a method of using this memory as a ring buffer and using it as if it were an endless memory (see, for example, Patent Document 1).
In writing to the memory in such a ring buffer operation, when the write pointer of the memory is incremented to reach the memory final address, the operation returns to the memory start address and repeats the same process again.
Similarly, in reading from the memory, similarly to the writing operation, when the read pointer of the memory is incremented to reach the memory final address, the operation returns to the memory start address and the same processing is repeated again.
As described above, by ringing the finite memory, the continuation of the data is continuously stored from the start address of the memory even if the memory final address is reached in the middle of the data, and the memory can be utilized very effectively.
The conventional use of the ring buffer memory is controlled so that the memory read pointer does not overtake the write pointer so that no underrun error occurs, and the write pointer does not overtake the read pointer. Memory write / read operations are controlled without errors.
When such a ring memory is used, there is a case where a page boundary can be recognized by fixing the size of one page buffer so that data can be taken out in units of pages or packets.
However, if the data length of one page varies, it is necessary to always secure a buffer of the same size even if it is much smaller than the buffer size of one page, and the memory always holds only a fixed page regardless of the data size. Can not do it.
In addition, when fetching into the memory as variable length record data size = 1 page buffer size, a method of communicating information such as page size as data by adding header information to the contents of the data like communication packet data There is also.
Furthermore, even when the header information is not included in the data, such as streaming data typified by video data, the number of valid data is counted for each page so that variable-length record data can be retrieved in units of pages. Get size information for each page and write data to memory.
On the other hand, it can be realized by storing the data size information in a separately prepared status storage memory. In this way, when the record data length is small, a larger number of pages can be held accordingly.
Japanese Patent Laid-Open No. 06-217094

However, when only the latest data finally stored in the memory is necessary, as in a data monitor device, when the data is read out in units of pages, the above-described status storage memory is already overwritten and lost. In order to read the page data remaining in the memory, a control means for managing whether the data has already been overwritten and data has been lost is necessary. .
Accordingly, an object of the present invention is to eliminate the memory data management means in consideration of the above-described situation, and to read out the latest part of the streaming data stored in the memory in page units with a simple circuit addition. Accordingly, it is an object of the present invention to provide a data input device that enables memory stored data to be read out with a simpler circuit than before even when receiving variable length record data of a plurality of pages and writing it into a ring buffer memory.

In order to solve the above-described problem, the invention according to claim 1 is configured such that when the image memory is configured as a ring buffer and the memory maximum address is exceeded, the memory address is returned to the top address and overwriting is performed. In a data input device including control means configured to be overwritten from the oldest data fetched into the image memory, the control means stores the image memory to be referred to when software reads the image memory. Information is stored in a dedicated FIFO memory, and when the image memory is ringed and a page is overwritten, the page status FIFO data is automatically read by the hardware, and the overwritten first page information is discarded. It is characterized by that.
According to a second aspect of the present invention, the detecting means for detecting the number of pages of data fetched into the image memory by software searches the FIFO empty flag every time before reading the page status FIFO, and becomes FIFO empty. In such a case, the reading of the page status FIFO is terminated, and the number of fetched pages can be known based on the number of FIFO readings so far.
According to a third aspect of the present invention, the detecting means for detecting the number of pages of data fetched into the image memory by software reads out the number of pages of data by reading out the remaining amount counter value of the page status FIFO. The page status FIFO is read by the number of times of the remaining amount counter value so that the data information of each page can be known.
According to a fourth aspect of the present invention, there is provided a fetched page which can be read from software in which the detecting means for detecting the number of pages of data fetched into the image memory by software counts the number of pages of data fetched into the image memory. A counter for counting the number is provided, and when the image memory is ringed and a page is overwritten, the counter is decremented by one.
According to a fifth aspect of the present invention, the means for detecting that the image memory has ringed and overwritten is performed by comparing the page status FIFO output with the value of the DMA address counter. .

The invention according to claim 6 refers to the FIFO empty flag, and when the DMA address in the state where the empty flag is set is equal to the FIFO output data, it is not overwritten and the empty flag is lowered. When the first DMA address is equal to the FIFO output data, it is detected that overwriting has occurred.
According to a seventh aspect of the present invention, when the depth of the page status FIFO is exceeded, it is detected that a full flag indicating that the FIFO output from the page status FIFO is empty is ON. The page status FIFO is automatically read by hardware, and the first page information stored in the FIFO is read and discarded.
According to the invention described in claim 8, when the fetched page number counter that can be read from the software that counts the number of pages of data fetched into the image memory exceeds the depth of the page status FIFO, it is counted. It is characterized by stopping the up operation.
The invention according to claim 9 has interface channels with a plurality of devices, and since each channel operates asynchronously with each other, the page status FIFO also includes a plurality of channels and all channels are provided. When the page is fetched exceeding the depth of the page status FIFO when not used, the unused channel FIFO also stores the used channel page information to store at least twice the page number information. It is possible to do it.
Further, the invention described in claim 10 has a mechanism that can notify the latest page information fetched to software using a status register separately from the page status FIFO. Features a data input device.
The invention according to claim 11 is characterized in that the data input device according to claim 1 has video interfaces for a plurality of channels, and each channel is allocated for each color.
According to a twelfth aspect of the present invention, the page number counter is counted up for a channel having no data in the same page of each channel, but the page status size is stored as zero in the page status FIFO. It features a data input device.

  According to the present invention, even when data exceeding the ring memory size is taken in, the latest page data stored in the ring memory is always held and can be read from software. In addition, when the record data length is small, a larger number of pages can be held accordingly.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic circuit diagram showing a hardware configuration example of a data input device according to the present invention. FIG. 1 shows a CPU 1 that executes software, a ROM 2 that stores programs and data, a video (VIDEO) I / F 3 that inputs data to a video interface of a target image device 15, and an image that is input to the video I / F 3. A DMAC 4 for transferring to and from the memory is shown.
Further, FIG. 1 shows a VIFIFO 5 for buffering video data input from the target image device 15 and converting it to a memory operating frequency, and data for outputting the data stored in the ring memory to the target image device 15. VOFIFO 6 is shown which converts the signal to the operating frequency of the video I / F 3.
Further, FIG. 1 shows a page status FIFO 7 for storing information about where (address) and how much (image size) the data input from the target image device 15 is stored, and various settings from software. A register 8 for storing, a memory I / F for storing video data taken in from the video I / F 3 in a ring memory, and a DRAM C 9 for performing memory access from software are shown.
Furthermore, FIG. 1 shows a ring memory (image memory) 10 for storing video data, a display I / F 11 for software to display and output data, and an operation unit for a user to operate the data input device. Modules such as an I / F 12, a disk (Disk) I / F 13 for storing the captured ring memory in an external storage device, and a network (Network) I / F 14 for communicating with a database server or a target image device via a network Is shown.
As long as these functions can be realized, the connection form between the modules may be arbitrary. FIG. 1 also shows a display device 16 connected to the display I / F 11, a keyboard 17 connected to the operation unit I / F 12, and a storage device 18 connected to a disk (Disk) I / F 13.
FIG. 2 is a schematic diagram showing a software configuration example of the data input device of the present invention. FIG. 2 shows an image input / output tool main 19 in charge of overall control of a data input tool and a user interface, and a video interface control 20 in charge of setting / control of video (VIDEO) I / F hardware. Is shown.
FIG. 2 also shows plug-ins 21-1, 21-2,. . . 21-N and an image conversion library 25 for controlling them, a database access 26 for using a database server on the network, a video interface driver 23 for directly controlling hardware, a network driver 24, and the like are installed.
As long as these functions can be realized, the module hierarchy, the type of operating system, and the like may be arbitrary. These software are stored in the ROM 2 or the like in FIG. 1, and the CPU 1 sequentially executes the software.

FIG. 3 is a schematic diagram illustrating a configuration example of a target image device (data transmission source device). FIG. 3 is a configuration example of a digital copying machine which is one representative example of target image equipment for inputting video data using the data input device of the present invention.
In FIG. 3, an image input from the image input unit 28 is sent to an image forming unit 32 via one or more image processing units 29 and 30 and an image memory (ring memory) 31 connected by various video interfaces. Hard copy. The number and variation of modules on the way may be arbitrary.
Further, it is not necessary that all the inter-module interfaces are video interfaces. The requirement is that at least the data transfer interface between modules is a video interface. A portion indicated by a dotted line in the figure is a form in which the data input device of the present invention is connected.
FIG. 4 is a diagram schematically showing ring control of the ring memory. FIG. 4 shows a state in which the memory address is returned to the top address and old data is overwritten when transferring data exceeding the ring range of the ring memory.
FIG. 5 is a timing chart showing the write / read control timing of the page head address FIFO. FIG. 5 shows a timing chart for performing a page status FIFO (first-in first-out) read operation when the ring memory is ringed and page data is overwritten.
FIG. 6 is a flowchart illustrating a page status FIFO read flow in the data input device. In FIG. 6, the page status FIFO data is read first (S1), then the page status FIFO empty flag is read (S2), and it is determined whether it is empty (S3). If it is empty, the flow ends. If it is not empty, steps (S1) and (S2) are repeated.
FIG. 7 is a timing chart when there is no page data. In particular, when capturing data from a color copying machine, even if each color data is unused (data is not transferred as video data), the page status of each color can be obtained by writing the page status with image size = 0. The operation | movement chart for maintaining correlation is shown.

A first embodiment of a data input device according to the present invention will be described with reference to FIGS. In the data input device according to the present invention having the hardware / software configuration as described above, the following operation is performed to capture page data from the image equipment.
In a state where the data input device according to the present invention is connected to the target image device, the user instructs the start of image capture from the operation unit I / F 12 of FIG. 1, and when the user captures a predetermined number of pages, the user captures the image data. Instruct stop.
During this time, data input in synchronization with video synchronization signals such as FGATE, LSYNC, and LGATE of the video I / F 3 are sequentially stored in the ring memory (image memory) 10. Here, FGATE = image sub-scanning valid signal, LSYNC = line synchronization signal, and LGATE = main scanning valid signal. This is a conventional video I / F and will not be described in particular.
Here, FIG. 4 is an example when the ring memory 10 is used as a ring buffer. The data input from the video I / F 3 is sequentially stored from the head address of the ring memory 10, and in the case of FIG. 4, the data reaches the final address of the ring memory 10 in the middle of the fifth page.
When the final address is reached, the memory address is returned to the first address, overwriting is performed from the data of the first page, and in this example, the image capture is completed in the middle of the storage area of the second page. At this time, the third to sixth pages are stored in the ring memory 10 (in this example, a part of the image data of the second page remains on the ring memory, but even a part is overwritten). In some cases, it is not handled as memory storage data).
In order for the software to access the page data stored in the ring memory 10, information on the start address and image size of each page data is required. However, these are stored in a dedicated FIFO memory for data fetching operation. When this FIFO is read out at the stage where is finished, the start address of each page and the image size can be known.
Here, the present invention is characterized in that the page status FIFO memory 7 is controlled so that only page information stored in the ring memory 10 is always stored. This method detects page overwriting. In such a case, the overwritten page status is deleted from the page status FIFO by reading the page status FIFO once.
Here, in the page overwriting detection, a comparator (not shown) detects that the ring memory write address (DMA address) has the same value as the page status FIFO output data (page head address).

In detail, the page status FIFO includes at least two types of page top address status FIFO for storing the page top address and page size status FIFO for storing the page size. FIG. 5 shows a timing chart of the write / read control of the page head address status FIFO.
As shown in FIG. 5, when the page head address status FIFO output data matches the DMA address, the page information that has been overwritten in the ring memory 10 is read by performing the page status FIFO read operation. As a result, the FIFO output data becomes the page information of the oldest page data stored in the ring memory 10.
In the above-described data input device, the user instructs the start of image capture from the operation unit I / F 12 of FIG. 1, and when the user captures a predetermined number of pages, the user instructs stop of image capture. Thereafter, for example, the software reads out the data in order to display the captured data on the display device 16.
At this time, first, the software reads the page status FIFO, and recognizes the head address and data size of the head page stored in the ring memory 10.

Next, a page status FIFO empty flag configured to be readable from software is checked. If the empty flag is set, the software determines that there is only information for one page read out first, and reads out data for one page.
However, if the empty flag has not been raised yet, page information to be read remains in the page status FIFO, so the software reads the page status FIFO again. Similarly thereafter, if the page status FIFO empty flag is not set, this operation is repeated (see FIG. 6).
With this operation, page data information corresponding to the number of times the page status FIFO is read is obtained, and data for a plurality of pages stored in the ring memory 10 can be read based on the page data information. The software can know the number of pages stored in the page status FIFO, and the number of page status FIFO reads can be determined.
In the data input device described above, first, the software reads the remaining status counter value output signal of the page status FIFO configured to be readable from the software, and recognizes the number of data (number of pages) stored in the page status FIFO. .
The software can read the page status FIFO for the number of pages obtained here, and obtain data information for a predetermined number of pages. Based on this, data for a plurality of pages stored in the ring memory 10 can be read.
According to this, the software can know the number of pages stored in the page status FIFO without fear of complicating the software by reading the empty flag every time, and the number of times of reading the page status FIFO can be determined.
Further, for example, when software reads out data to display the captured data on the display device 16, the software first refers to an image capture page number counter that is configured to be readable from the software, and how many pages of data are stored. Recognize whether it was imported.
This data fetch page number counter is incremented by 1 after fetching data in page units, and is controlled to decrement by 1 when overwriting is detected as described in the first embodiment, and when the fetch operation is completed. The counter value is held as it is and is controlled to be cleared to zero at the start of the next capturing operation. That is, the counter value is held regardless of the number of software reads.
This counter value does not change even if it is read from the software. Therefore, the number of pages that the hardware instructs the software to read is understood, and the problem that occurs during the development of this device is caused by the hardware, or by the software. It will be easier to identify things.
Therefore, it is simplified by using the page status FIFO output in the memory overwrite detection circuit. The overwriting detection circuit only needs to constantly compare the DMA address counter value and the page status FIFO output, the detection circuit is simple, the gate scale can be suppressed, and the reliability is improved.

For page overwrite detection, for example, a DMA address counter can be used after the start of data fetching simply by detecting that the ring memory write address (DMA address) has the same value as the page status FIFO output data (page head address). Since the condition that the value = 0 and the page status FIFO output = 0 may be satisfied, the data input device according to the present invention excludes the satisfied condition immediately after the start of image capturing from the page overwrite detection condition. It is a feature.
The means for eliminating is performed by ANDing the page overwrite condition when the empty flag of the page status FIFO is not set. Here, since this condition is always satisfied, the page status FIFO clears the data in the FIFO by performing all clear immediately after the data fetch start instruction.
This is to prevent malfunction because data is already stored in the FIFO when the data capturing operation is repeated. As a result, the page status FIFO empty flag is once set, and thereafter, when comparing the DMA address-FIFO output value when actually fetching data, the occurrence of overwriting is not detected.
In the memory overwrite detection circuit, the FIFO output may be the top address (= 0) by default. At this time, the overwriting detection may be erroneously detected at the head of writing to the ring memory 10.

In the data input device described above, if the depth capacity of the page status FIFO is 3, for example, in the example of FIG. 4, the ring memory 10 can store at least 4 pages, but the FIFO capacity for storing the data information is 3 Sometimes there are only pages.
In such a case, the software can obtain information for only three pages of data, but at this time, the page status FIFO must hold the latest three pages of data information taken in.
Therefore, in this example, when the next page write occurs when the FIFO full flag signal output from the FIFO is raised when all the FIFO capacity for three pages is stored, the page status FIFO is first set to 1. The page is read, and the FIFO is written after the full flag falls to zero.
A page status FIFO that stores the page size, head address, and the like of the captured image has a finite depth capacity, and therefore cannot cope with page status information for the number of pages exceeding the depth capacity. Therefore, when the number of pages exceeding the depth of the page status FIFO can be stored in the ring memory 10, the information about the latest page status FIFO depth fetched among them can be stored from the software. The latest page data information that is always captured can be read.

In the data input device described above, if the page status FIFO depth capacity is 3, for example, the ring memory 10 can store at least 4 pages in FIG. 4, but the FIFO capacity for storing the data information is 3 pages. Sometimes there is only one.
In such a case, the software can obtain information for only three pages of data, but at this time, the page status FIFO must hold the latest three pages of data information taken in.
Therefore, in this example, when the next page is written when the FIFO full flag signal output from the FIFO is raised when all the FIFO capacity data for three pages is stored, the fetched page counter value is held. It is configured. As a result, it is possible to read out the latest page for the depth of the page status FIFO.
In a data input device having multiple channels of video I / F3, an improvement is made so that page status FIFOs of unused channels can be serially connected and used as if the FIFO depth capacity is doubled. I have to.
For example, when two FIFO memories are used, data is first stored only in one of the FIFO memories. When the full flag is set, data is stored in the other FIFO memory.
In addition, when the ring memory is overwritten, in addition to reading data from one FIFO memory storing the head data, reading is also performed from the other FIFO, and the read data is written to one FIFO. .
In the data input device described above, since the depth capacity of the page status FIFO is small, the software accesses only the pages corresponding to the page status FIFO even though more page data is stored in the ring memory 10. Can not do it.
In particular, when the page size is small, when it is desired to fetch more pages into the ring memory 10, it is possible to reduce the rate at which the number of fetched pages is limited due to the depth capacity of the page status FIFO.
In addition to the data input device described above, the page head address and data size data to be stored in the page status FIFO are written in a register that can be read from software.
The write timing is equivalent to the write timing to the page status FIFO, and this register always stores the page top address and data size of the latest page and can be read from software at any time.

However, for example, when the software polls the page data input from video data and the next page data, that is, when the FGATE signal is negated, this register is read at this timing, and the latest captured data is captured in real time. It is possible to display the image on the display device 16 and the like.
In the above-described data input device, the software can read the page status FIFO after the data fetching operation is completed, so that a plurality of pages stored in the ring memory 10 can be read. As soon as data is imported, there is a request from the user to display the latest imported page.
This request is made even during data capture without fear that if the FIFO is read out during data capture, the contents of the ring memory will not match the FIFO contents, and correct data cannot be read out. The latest loading page can be read and displayed in real time.
The data input device described above is equipped with a plurality of channels, and for example, cyan data, magenta data, yellow data, and black data are input to each channel. Each channel operates asynchronously, but by configuring each channel like a data input device, the pages for each color are correlated, and the number of pages specified by the software always matches each color.
Accordingly, each color data can be read out by software, and can be displayed and combined with each color. In the data input device, in particular, color image data can be captured for a plurality of pages for each color.
For example, when this data input device captures a print image of a general digital full-color copier, when channel 1: cyan, channel 2: magenta, channel 3: yellow, channel 4: black are allocated, combined display for each page The data actually output on the paper surface by the copying machine can be displayed in full color on the display device of the data input device.

In the data input device described above, there may be a page on which no data is loaded depending on the channel. In such a case, the data size is set to 0 and data is written to the page status FIFO.
For example, consider the case where the video I / F is controlled by the FSYNC signal and the FGATE signal as shown in FIG. The FSYNC signal is a synchronization signal that is always output at the head of the page, and the FGATE signal is a signal that indicates valid data of the page.
As shown in FIG. 7, after the FSYNC signal is asserted, data is input in synchronization with the FGATE signal indicating the valid image range. This time indicates that no data has been transferred, and under this condition, size = 0 is written in the page status FIFO.
The next FSYNC signal is not generated when there is no data in the last page of data capture, but at this time, the size 0 is written in the page status FIFO by the stop signal of image capture stop.
Even when there is a channel with no data in the same page for each channel, there is no problem that it is impossible to generate a single color image by combining the channel data. Even when color images and monochrome images are mixed, or even in an image device that does not output colors that are not used even in full-color images, the page information of each channel is the same and the page information can be correlated, so composite display of the specified page Etc. can be performed.
The present invention can be applied to, for example, a data monitoring apparatus that monitors image data in an image device such as a laser printer or a digital copying machine.

It is a schematic circuit diagram which shows the hardware structural example of the data input device by this invention. It is the schematic which shows the software structural example of the data input device of this invention. It is the schematic which shows the structural example of a target image apparatus (data transmission origin apparatus). It is a figure showing typically ring control of a ring memory. It is a timing chart showing the write / read control timing of the page head address FIFO. It is a flowchart explaining the page status FIFO read flow in the data input device. It is a timing chart at the time of mixing without page data.

Explanation of symbols

1 CPU
3 Video (VIDEO) I / F
7 Page Status FIFO
10 Image memory (ring memory)
15 Target image equipment

Claims (12)

  The image memory is configured as a ring buffer, and when the maximum memory address is exceeded, the memory address is returned to the top address and overwriting is performed, and the oldest data captured in the image memory is overwritten. In the data input device comprising the control means, the control means stores the storage information of the image memory, which is referred to when software reads the image memory, in a dedicated FIFO memory, and the image memory rings to store the page information. A data input device characterized in that, when overwriting occurs, the hardware automatically reads out the data of the page status FIFO, and reads out and discards the first page information overwritten.   The detection means for detecting the number of pages of data fetched into the image memory by software searches the FIFO empty flag every time before reading the page status FIFO, and when the FIFO is empty, reads the page status FIFO. 2. The data input device according to claim 1, wherein the number of fetched pages can be known based on the number of times the FIFO has been read so far.   The detecting means for detecting the number of pages of data fetched into the image memory by software can detect how many pages of data are stored by reading the remaining amount counter value of the page status FIFO, 2. The data input device according to claim 1, wherein the page status FIFO is read by the number of times of the remaining amount counter value so that the data information of each page can be known.   The detection means for detecting the number of pages of data fetched into the image memory by software is provided with a counter for counting the number of fetched pages readable from software for counting the number of pages of data fetched into the image memory, 2. The data input device according to claim 1, wherein when the page is overwritten and the page is overwritten, the counter is decremented by one.   5. The means for detecting that the image memory is ringed and overwritten occurs by comparing the page status FIFO output with a value of a DMA address counter. Data input device.   Referring to the FIFO empty flag, if the DMA address in the state where the empty flag is set is equal to the FIFO output data, it is not overwritten, and the first DMA address after the empty flag is lowered is equal to the FIFO output data. 5. The data input device according to claim 1, wherein overwriting is detected in some cases.   When the depth of the page status FIFO is exceeded, if it is detected that the full flag indicating that there is no free space in the FIFO output from the page status FIFO is detected, the page status FIFO is automatically set by the hardware. 5. The data input device according to claim 1, wherein the first page information read out and stored in the FIFO is discarded.   The count-up operation is stopped when a fetched page number counter readable from software that counts the number of pages of data fetched into the image memory exceeds a depth of the page status FIFO. 7. The data input device according to 7.   Since there are a plurality of interface channels with a plurality of devices and each channel operates asynchronously with each other, when the page status FIFO is provided for a number of channels and not all channels are used, the depth of the page status FIFO The page number information of at least twice can be stored in the FIFO of the unused channel by additionally storing the page information of the used channel when more than the page fetch is performed. The data input device according to 7 or 8.   10. The data input device according to claim 1, wherein the fetched latest page information can be notified to software using a status register separately from the page status FIFO.   The data input device according to claim 1, further comprising a video interface for a plurality of channels, wherein each channel is allocated for each color.   12. The data input device according to claim 11, wherein the page number counter is counted up for a channel having no data in the same page of each channel, but the page status size is stored as zero in the page status FIFO.

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