JP2002140287A - Information processing device and dma transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save the storage capacity of an image memory by cutting off unnecessary image data for not storing them in the image memory, and to improve the productivity by setting a timing to start DMA in DMA transfer output from the image memory against DMA transfer input of the image data to the image memory. SOLUTION: A format information 57 for descriptor information includes an interrupt instruction bit 58, which instructs a CPU in a system control part for the existence/absence of an interrupt signal transmission after DMA transfer of the image data based on one of the descriptor information is finished, and a transfer instruction bit 59 instructing the image memory whether DMA transfer of the image data is to be carried out or the image data are to be read and discarded without any DMA transfer. It is instructed that the interrupt signal is transmitted to the CPU in the system control part when the interrupt instruction bit 58 is one while the interrupt signal is not transmitted if the bit is zero. When the transfer instruction bit 59 is one, DMA transfer of the image data to the image memory is carried out, while the image data are read and discarded without any DMA transfer when the bit is zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an information processing apparatus and a DMA transfer method.

[0002]

2. Description of the Related Art In recent years, digitalization of copiers has progressed, and various techniques for processing and editing using an image memory have been proposed. As one of such techniques, there is a function called an electronic sort in which a specified number of copies are collectively output by storing image data of a plurality of documents in an image memory, thereby eliminating a sorting operation.

In this case, if the image data is stored in the semiconductor memory as it is in order to hold a plurality of image data, a memory corresponding to the data amount of the stored number is required, and the memory cost is reduced. The following means are generally used for the reason that the number becomes large.

[0004] A semiconductor memory and a storage memory are used in combination, and a secondary storage device such as a hard disk which is lower in cost than the semiconductor memory is used as the storage memory.

[0005] A semiconductor memory is used as a storage memory, and image data is compressed using a compression process to reduce the amount of data per image, thereby reducing the total memory amount.

[0006] Multiple image input / output means (image scanner, printer controller, file server, fax
Controller, etc.) to share the same image memory.

In order to execute input / output of image data to / from an image memory, a DMA (Direct Memory Acces
s) A memory controller (DMA controller) using a data transfer method is often used. DM
In the A data transfer method, there is a technique for transferring data to a specific area of an image memory based on memory area management information called descriptor information (see Japanese Patent Application Laid-Open No. 6-103225).

[0008]

In the above-described DMA data transfer method using descriptor information, image data of one image is divided into a plurality of pieces of image data, and each divided portion is divided by using different pieces of descriptor information. It is also possible to perform data transfer, for example, by using an image memory in the form of a ring buffer, it is possible to execute input / output of image data with a memory capacity smaller than the capacity of the target image data. it can.

By the way, image data input from image input means (image scanner, printer controller, file server, facsimile controller, etc.) is centered (transfer paper of a larger size than image data input by the image scanner). For example, when forming an image, an image based on the image data is placed at the center of the transfer paper and printed out), or the image is input to the image memory after adding a margin such as a binding margin. Conventionally, when such image editing / processing functions are realized, image editing is performed by securing a margin area to be added or a memory area larger than the input image data (corresponding to the transfer paper size).

In this case, by performing image editing, the memory capacity required for processing increases, and preprocessing (memory data clearing outside the input image data area or initial processing) for using the increased memory area is further performed. ) Occurs and the processing time is lengthened, resulting in a problem that the productivity of the copying machine is reduced.

As a result of the image moving process, even if there is unnecessary input image data (not output to the printer or stored in the image memory), the unnecessary memory area is retained. It is conceivable that the processing is performed as it is.

Further, a plurality of image input / output means (image scanner, printer controller, file server, FA
In an image forming apparatus such as a digital multi-function peripheral having an X controller, etc., a plurality of image data input / output requests may be simultaneously made to a single image memory.
Taking the operation of outputting the image data input from the image scanner to the image memory to the printer as an example, the following series of requests 1 to 5 is performed.

Requirement 1. Input image 1 having binding margin from image scanner to image memory (scanner input) Request 2. 2. Output image 1 to printer (request while request 1 is being executed) 3. Input the image 2 having the binding margin from the image scanner to the image memory (required during the execution of the request 2). 4. Output image 2 to printer (request while request 3 is being executed) An image 3 having a binding margin is input from the image scanner to the image memory (requested during execution of the request 4). In such a case, in the operation control of the image memory,
If a plurality of data transfer requests can be processed simultaneously in parallel based on a plurality of data transfer requests so as to minimize the idle time for the execution, the productivity of the digital multi-function peripheral is improved.

That is, in the above example, if the same memory area of the image memory is read during the image data transfer of the request 1 (input to the image memory) and the request 2 is output to the printer, the processing time Is greatly reduced.

Similarly, during the data transfer of the request 2 (output from the first storage device to the printer), another memory area is secured and the data transfer of the request 3 (input to the image memory) is executed. , The time to process the entire request is greatly reduced.

Further, the same memory area used in the request 2 is selected as the memory area for the data transfer in the request 3, and an operation of overwriting a portion of the memory area where the data transfer of the image 1 has been completed is performed. By performing the control, the required capacity of the image memory can be reduced, and the manufacturing cost of the apparatus can be reduced.

However, when such a process is performed, output from a memory area in which an input operation to the image memory including an image processing process for adding a binding margin is not completed is prohibited (first embodiment). (Data input (overwrite) to the memory area where output from the storage device is not completed is prohibited.)
It is necessary.

Specifically, when image data is input to the image memory, the binding margin (margin data) at the leading end of the image in the sub-scanning direction is deleted, and the image data subsequent to the margin data is input to the image memory. When an image movement operation (which may be called “minus binding margin”) that performs (transfer) is requested, the margin data at the leading end of the image in the sub-scanning direction is discarded without being transferred to the image memory. The timing at which the blank data portion is completely discarded is detected, and input of image data to the image memory is started. Switching of input data transfer from margin data to image data needs to be completed almost instantaneously.

An object of the present invention is to save the storage capacity of the first storage device by extracting unnecessary image data and not storing it in the image memory.

An object of the present invention is to provide a DMA transfer input of image data to a storage device, while taking a timing of starting a DMA when outputting a DMA transfer from the storage device,
It is to improve productivity.

[0021]

According to a first aspect of the present invention, there is provided an information processing apparatus in which a CPU performs information processing, a first storage device storing target data to be processed, and A plurality of pieces of descriptor information corresponding to each of the divided portions are created so that the input of the target data to one storage device is performed by dividing the image data of one image into a plurality of pieces and sequentially performing DMA transfer independently of the CPU. Descriptor information creating means, a second storage device for storing the created plurality of pieces of descriptor information, and a DMA controller for sequentially executing the DMA transfer based on the stored plurality of pieces of descriptor information. The creating means reads and discards image data to be transferred at the time of the DMA transfer in each of the descriptor information. Serial is an information processing apparatus characterized by including a transfer instruction data for instructing whether to forward to the first or not transferred to the storage device as the first storage device to the DMA controller.

Therefore, even when margins such as a binding margin and other unnecessary data exist in the image data to be DMA-transferred, the unnecessary image data can be extracted and not stored in the image memory. The storage capacity of the first storage device can be saved.

According to a second aspect of the present invention, in the information processing apparatus according to the first aspect, the descriptor information creation means includes the following in the respective descriptor information after the end of the DMA transfer based on the descriptor information. Before the start of the DMA transfer based on the descriptor information, the C
It is characterized by including interrupt instruction data for instructing the DMA controller whether or not to output an interrupt signal to the PU.

Therefore, the interrupt signal to the CPU is set to DM
In contrast to the A transfer input, the first storage device can be used to set the timing of DMA activation when the image data is DMA transferred and output, thereby improving the productivity of the image processing apparatus.

The third aspect of the present invention is the first or second aspect.
In the information processing device described in (1), when there is a margin at the beginning of the image data in the sub-scanning direction, the descriptor information creating means creates the leading descriptor information corresponding to the number of lines of the margin width. The transfer instruction data included in the descriptor information is characterized in that image data to be transferred during the DMA transfer is discarded and not transferred to the first storage device.

Therefore, if there is a margin such as a binding margin at the beginning of the image data in the sub-scanning direction, the margin can be extracted and not stored in the image memory, so that the storage capacity of the first storage device is reduced. Can be saved.

According to a fourth aspect of the present invention, in the information processing apparatus according to any one of the first to third aspects, an image scanner for reading an image of a document and outputting image data is provided. A printer engine for forming an image on a sheet, wherein the first storage device inputs and outputs image data between the image scanner and the printer engine.

Therefore, in the case where the information processing apparatus is an image forming apparatus that reads an image of a document and forms an image on paper, the same operation as the invention according to any one of claims 1 to 3,
The effect can be achieved.

According to a fifth aspect of the present invention, the information processing is performed by a CP.
U, wherein the input and output of the image data to and from the first storage device for storing the image data to be processed is performed by DMA transfer independently of the CPU.
In the MA transfer method, the input of the image data to the first storage device is performed by dividing the image data of one image into a plurality of pieces and sequentially performing the DMA transfer by a plurality of the plurality of pieces corresponding to the respective divided portions. A descriptor information creating step of creating descriptor information and storing the descriptor information in a second storage device; and a DMA transfer step of sequentially executing the DMA transfer based on the stored plurality of descriptor information by a DMA controller. The descriptor information creation step includes, for each of the descriptor information,
Transfer instruction data for instructing the DMA controller whether the image data to be transferred in the DMA transfer is discarded and not transferred to the first storage device or transferred as it is to the first storage device is included. D
This is the MA transfer method.

Therefore, even when margins such as a binding margin and other unnecessary data exist in the image data to be DMA-transferred, the unnecessary image data can be extracted and stored in the image memory. The storage capacity of the first storage device can be saved.

According to a sixth aspect of the present invention, in the DMA transfer method according to the fifth aspect, the descriptor information creating step includes the step of adding the following to the respective descriptor information after the end of the DMA transfer based on the descriptor information. Before the start of the DMA transfer based on descriptor information, interrupt instruction data for instructing the DMA controller whether or not to output an interrupt signal to the CPU is included.

Therefore, the interrupt signal to the CPU is set to DM
In contrast to the A transfer input, the first storage device can be used to set the timing of DMA activation when the image data is DMA transferred and output, thereby improving the productivity of the image processing apparatus.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.

FIG. 1 is a conceptual diagram illustrating a schematic configuration of a digital copying machine 1 according to an embodiment of the present invention. The digital copying machine 1 implements the information processing apparatus of the present invention, and includes an image reading unit 2, an image forming unit 3,
AX unit 4, selector unit 5, storage unit 6, operation unit 7
And a system control unit 8.

The image reading section 2 exposes and scans the document G by a movable exposure lamp 12 along a document table 11, and receives the reflected light by a CCD image sensor 16 via an optical system such as mirrors 13 to 15. Thus, the image scanner reads the image of the document G. Then, in an IPU (image processing unit) 17, processing such as shading correction is performed on the image signal output from the CCD image sensor 16, A / D converted to an 8-bit digital signal, and scaling processing is performed. Image processing such as dither processing is performed. The processed image data is output together with the image synchronization signal. The scanner control unit 18 captures detection signals of various sensors and outputs control signals to actuators such as various drive motors in order to execute the process of the image reading unit 2 described above. Also, IP
Various parameters are set in U17.

Here, the image synchronization signal output from the IPU 17 of the image reading section 2 will be described with reference to the timing chart shown in FIG. That is, the frame gate signal (/ FGATE) is a signal indicating an image effective range for the image area in the sub-scanning direction, and image data is valid while this signal is at the L level (low active). The frame gate signal (/ FGATE) is asserted at the falling edge of the line synchronization signal (/ LSYNC), or
Negated. The line synchronization signal (/ LSYNC) is asserted for a predetermined number of clocks at the rising edge of the pixel synchronization signal (PCLK), and after the rising of this signal, the image data in the main scanning direction becomes valid after a predetermined clock. The transmitted image data is one for one cycle of the pixel synchronization signal (PCLK). The image data is sent out as raster format data starting from the arrow. The effective sub-scanning range of image data is usually determined by the size of the transfer paper.

As shown in FIG. 1, in the image forming section 3 which is a printer engine, the photosensitive member 22 is uniformly charged by the charging charger 21 and an image is read from the charged photosensitive member 22 which rotates at a constant speed. Exposure is performed with laser light modulated by the optical writing unit 23 based on the image data output from the unit 2 to form an electrostatic latent image. The electrostatic latent image on the photoreceptor 22 becomes a visible toner image by being developed with toner by the developing device 24. Then, the transfer paper, which has been fed in advance from the paper feed tray 26 by the paper feed roller 25 and is kept on standby by the registration roller 27, is transported at a timing with the photoconductor 22, and is transferred by the transfer charger 28. The upper toner image is electrostatically transferred to transfer paper. Thereafter, the transfer paper is separated from the photoconductor 22 by the separation charger 29, and the toner image on the transfer paper is fixed to the fixing device 30.
Is fixed by heating, and the discharge tray 31 is driven by the discharge roller 31.
2 is discharged. On the other hand, the toner remaining on the photoconductor 22 after the electrostatic transfer is removed by the cleaning device 33.
The photoconductor 22 is neutralized by the neutralization charger 34. The plotter control unit 35 captures detection signals of various sensors and outputs control signals to actuators such as various drive motors in order to execute the process of the image forming unit 3 described above. The image forming unit 3 can use not only the electrophotographic method as described above but also various printing formats such as an ink jet method.

The operation unit 7 includes various keys for receiving various operations from the user, an LCD display for displaying various messages to the user, and the like.

The system control unit 8 includes a CPU and performs various information processing. That is, an input from the user to the operation unit 7 is detected, and the image reading unit 2, the storage unit 6, the image forming unit 3,
The setting of various parameters to the FAX unit 4 and the instruction to execute a process are performed by communication.

The facsimile unit 4 converts the image data read by the image reading unit 2 according to an instruction from the system control unit 8 into G
(3) Binary compression is performed based on the G4 facsimile data transfer rules and transferred to an external destination via a telephone line.
Also, receiving image data from outside via a telephone line,
This image data is restored to binary image data,
The image is formed in the image forming unit 3.

The selector unit 5 changes the state of the selector in accordance with an instruction from the system control unit 8 and changes the state of the selector.
The source of the image data for forming the image is switched to an image signal output from any one of the image reading unit 2, the storage unit 6, and the FAX unit 4.

The storage unit 6 stores image data of the document G normally input from the IPU 17, and is used for copy applications such as repeat copy and rotation copy. It is also used as a buffer memory for temporarily storing the binary image data from the FAX unit 4. These data storage instructions are given by the system control unit 8.

Next, a detailed configuration of the storage unit 6 will be described with reference to FIG. As shown in FIG. 3, the image input / output DMAC (in the description of the embodiment of the present invention,
“DMA controller” is simply called “DMAC”.
Reference numeral 1 denotes a CPU and a logic LSI, which communicates with the memory control unit 42 to receive a command, performs an operation setting in accordance with the command, and performs image input / output DMAC.
41 to transmit status information to inform the status of itself. When an image input command is received, the input image data is packed as 8-pixel memory data according to the input image synchronization signal, and output to the memory control unit 42 together with the memory access signal as needed. When receiving an image output command, it outputs image data from the memory control unit 42 in synchronization with an output image synchronization signal.

The image memory 43 is a memory for storing image data, and is composed of a semiconductor storage element such as a DRAM. In this example, the total amount of memory is 2 at 400 dpi.
The total of 8 MB is 4 Mbytes for the A3 size of the value image data and 4 Mbytes for the electronic sort storage. The image memory 43 is controlled by reading and writing from the memory control unit 42.

The memory control unit 42 is composed of a CPU and a logic LSI, communicates with the system control unit 8, receives a command, sets an operation according to the command, and notifies the state of the storage unit 6. Send status information.

The operation commands from the system control unit 8 include image input, image output, compression, decompression, and the like. Commands such as image input and image output include the image input / output DMAC 41.
Sent to. Commands such as compression and decompression are transmitted to the image transfer DMAC 44, code transfer DMAC 45, and compression / decompression unit 46, respectively.

FIG. 4 is a block diagram showing a detailed configuration of the memory control unit 42. As shown in FIG.
Reference numeral 7 denotes an image input / output DMAC 41 and an image transfer DMAC 4
4. Arbitrate the memory access request signal from the code transfer DMAC 45 and output an access permission signal. Arbiter 4
7 has a built-in refresh control circuit, the priority order is the refresh control circuit, the image input / output DMAC 41, the image transfer DMAC 44, and the code transfer DMAC 45. Actively output the access permission signal. Further, it outputs an enable signal and selects an address of the image memory 43, and outputs a trigger signal indicating the start of memory access to the access control circuit 48.

The input physical address is determined by a signal from the access control circuit 48 as a DRAM which is a semiconductor memory.
Are divided into a row address and a column address corresponding to the image memory 43 constituted by the image memory 43, and output to an 11-bit address bus. In accordance with the access start signal from the arbiter 47, the DRAM control signals (RAS, CAS, W
E) is output to the image memory 43.

The image transfer DMAC 44 is composed of a CPU and a logic LSI, communicates with the memory control unit 42 to receive a command, performs an operation setting according to the command, and sets a state as shown in FIG. Is transmitted as status information to inform the user. When a compression command is received, a memory access request signal is output to the memory control unit 42. When the memory access permission signal is active, image data is received and transferred to the compression / expansion unit 46. Further, it incorporates an address counter that counts up in response to a memory access request signal, and outputs a 22-bit memory address indicating a storage location where image data is stored.

The code transfer DMAC 45 is composed of a CPU and a logic LSI, communicates with the memory control unit 42, receives a command, sets an operation in accordance with the command, and transmits it as status information to notify a state. I do. When a decompression command is received, a memory access request signal is output to the memory control unit 42, and when the memory access permission signal is active, image data is received and transferred to the compression / decompression unit 46. Further, it incorporates an address counter that counts up in response to a memory access request signal, and outputs a 22-bit memory address indicating a storage location where image data is stored.

The compression / expansion unit 46 includes a CPU and a logic L
It is configured with an SI, communicates with the memory control unit 42, receives a command, performs operation setting according to the command,
Also, it is transmitted as status information to inform the state. The compression / expansion unit 46 compresses the binary image data by the MH encoding method.

FIG. 5 is a schematic diagram of the internal configuration of the image memory 43. As shown in FIG. 5, the image memory 43 stores a second descriptor information 53 (see FIG. 6) described later.
Is divided into a descriptor area 51, which is a storage device, and an image area 52, which is a first storage device for storing image data.

FIG. 6 is a block diagram showing the data structure of the descriptor information 53 used in the DMA transfer processing using the image memory 43. In this DMA transfer processing, 1
In order to divide the image data of a single image into a plurality of pieces, prepare descriptor information 53 for each of the divided portions, and transfer the image data of one image by DMA, a plurality of pieces of descriptor information 53 are created. The descriptor information 53 described below is used by the image input / output DMAC 41.

As shown in FIG. 6, chain destination address 5
4 is address data in which the next descriptor information 53 is stored. Also, the next descriptor information 5
If there is no 3, a numerical value indicating the end is stored.
The data storage destination address 55 is address data in which image data to be subjected to DMA transfer is stored. The data transfer word number 56 indicates the capacity of the data to be transferred by the number of words. The format information 57 indicates the format of the image data to be DMA-transferred.

As shown in FIG. 7, the format information 57
After the completion of the DMA transfer of the image data based on one piece of descriptor information 53, the CPU of the system control unit 8
Instruction bit 58 for instructing whether an interrupt signal is transmitted or not
DMA transfer of image data to the image memory 43,
A transfer instruction bit 59 for instructing whether to read and discard the image data without performing the DMA transfer. Interrupt instruction bit 5
When 8 is "1", an interrupt signal is transmitted to the CPU of the system control unit 8, and when it is "0", it is instructed not to transmit. When the transfer instruction bit 59 is "1", the image data is DMA-transferred to the image memory 43.
Instruct each to discard without reading MA.

Next, the DMA transfer processing of the image data performed by using the image memory 43 will be described. The example described below is for the case of performing DMA transfer of image data from the image reading unit 2 to the image memory 43.

First, as shown in FIG. 8, when there is a request to transfer image data from the image reading unit 2 to the image memory 43 (Y in step S1), the system control unit 8 .. Are generated.

That is, from the image reading unit 2 to the image memory 4
It is determined whether there is a request to create a margin as a margin at the leading end in the sub-scanning direction for one image to be transferred to No. 3 (step S2). When there is a request to create a binding margin at the leading end of the image in the sub-scanning direction (Y in step S2), the leading descriptor information 53 of the plurality of descriptor information 53 to be created is replaced with the leading end. And the transfer instruction bit 59, which is the transfer instruction data, is set to "0", and the interrupt instruction bit 58, which is the interrupt instruction data, is set to "1" (step S3). ).

Next, for one image to be transferred from the image reading section 2 to the image memory 43, it is determined whether or not there is a request to create a binding margin at the rear end in the sub-scanning direction. (Step S4). If there is a request to create a binding margin at the rear end (Y in step S4), the remaining descriptor information 53, 53,... Is created as follows (step S5). That is, when the first descriptor information 53 is created in step S3, the first descriptor information 53 is created sequentially from the second descriptor information 53, and when the first descriptor information 53 is not created in step S3,
It is created sequentially from the first descriptor information 53.

In this case, the remaining descriptor information 53, 53,... Are created so that the number of lines of image data excluding the binding margin at the rear end becomes the number of lines of image data stored in the image memory 43. I do. That is, the single descriptor information 53 is created corresponding to the image data other than the binding margin at the rear end portion, or the image data other than the binding margin at the rear end portion is divided into a plurality of pieces to correspond to each divided portion. To generate a plurality of descriptor information 53. At that time, the value of the data transfer word number 56 of each descriptor information 53 to be created is selected so that only the image data other than the binding margin at the rear end portion is stored in the image memory 43.
The number of lines of image data other than the binding margin at the rear end portion is the number of lines of image data stored in the image memory 43. Then, the transfer instruction bit 59 of each descriptor information 53 to be created is set to “1”, and the interrupt instruction bit 58 is set to “1”.

If there is no request to create a binding margin at the rear end (N in step S4), the remaining descriptor information 53, 53,... Are created as follows (step S4).
6). That is, when the first descriptor information 53 is created in step S3, the first descriptor information 53 is created sequentially from the second descriptor information 53, and when the first descriptor information 53 is not created in step S3, the first descriptor information 53 is created sequentially from the first descriptor information 53. Creating the step S
Same as 5.

However, in step S6, since there is no binding margin at the rear end portion, the remaining descriptor information 53 and the remaining descriptor information 53, so that the number of lines of the remaining image data becomes the number of lines of the image data stored in the image memory 43. 53, ... are created. Steps S5 and S6 implement a descriptor information creation unit and a descriptor information creation step.

The above descriptor information 53 is
It is created in the descriptor area 51 of the image memory 43. The system control unit 8 includes the descriptor information 53, 5
Are generated, a command for instructing the start of DMA transfer processing is output to the memory control unit 42 (step S3).
7), the process ends.

Next, the DMA transfer processing performed using the descriptor information 53 will be described. That is, when the memory control unit 42 receives the command output in step S7, it activates the image input / output DMAC 41, and the image input / output DMAC 41 performs the processing shown in FIG.

That is, the image input / output DMAC 41 transfers the descriptor information 53, 53,... Stored in the descriptor area 51 of the image memory 43 to the image input / output D
It is stored in a register (descriptor storage register) prepared in the MAC 41 (step S11). And
.. Are processed in order from the first one. That is, the value of the transfer instruction bit 59 is determined (step S12), and when this value is "1" (Y in step S12), the image data is DMA-transferred to the image area 52 of the image memory 43 as it is (step S12). S1
3) If it is "0" (N in step S12), D
The image data is discarded without being transferred to the MA, and the image data is not stored in the image area 52 (step S14). Step S13, S
14 implements a DMA transfer process. Step S
After the processing in steps S13 and S14, the value of the interrupt instruction bit 58 is determined (step S15). When this value is "1" (Y in step S15), an interrupt signal is transmitted to the CPU of the system control unit 8. (Step S16). Step S1 above
The processing of 2 to S16 is performed sequentially from the first descriptor information 53 to the last descriptor information 53 (N in step S17), and when the processing of the last descriptor information 53 is completed (Y in step S17), the processing ends. .

According to the digital copying machine 1 described above,
Even when unnecessary data such as a binding margin is present in the image data to be DMA-transferred to the image memory 43, the unnecessary image data can be extracted and not stored in the image memory 43. Storage capacity can be saved. In consideration of performing image movement after inputting image data to the image memory 43,
Whether to discard the image data can be selectively performed.

The image data is stored in the image memory 43 by the DM.
In response to the A transfer input, an interrupt signal to the CPU of the system control unit 8 is sent to the image data from the image memory 43 by DMA.
This can be used to determine the timing of starting the DMA when transferring and outputting, and the productivity of the digital copying machine 1 can be improved.

The storage section 6 can compress and decompress the image data stored in the image memory 43 by using the compression / decompression device 46. In this case, the transfer of the image data from the image memory 43 to the compression / expansion unit 46 is performed by the image transfer DM.
When the code data after compression and decompression is returned from the compression / decompression device 46 to the image memory 43 using the AC 44, the code transfer DMAC 45 is used. Image transfer DMAC 44,
The operation of the code transfer DMAC 45 can also be performed according to the descriptor information.

Although the embodiment of the present invention has been described with reference to an example in which the present invention is applied to a digital copying machine, it goes without saying that the information processing apparatus of the present invention can be applied to various information processing apparatuses such as a PC.

[0070]

According to the first aspect of the present invention, even when margins such as a binding margin and other unnecessary data exist in the image data to be DMA-transferred, the unnecessary image data is extracted and stored in the image memory. Since it is possible not to store the data, the storage capacity of the first storage device can be saved.

According to a second aspect of the present invention, in the information processing apparatus according to the first aspect, the interrupt signal to the CPU is provided by a DM
In contrast to the A transfer input, the first storage device can be used to set the timing of DMA activation when the image data is DMA transferred and output, thereby improving the productivity of the image processing apparatus.

The third aspect of the present invention is the first or second aspect.
In the information processing apparatus described in the item (1), if there is a margin such as a binding margin at the beginning of the image data in the sub-scanning direction, the margin can be extracted and not stored in the image memory. Storage capacity can be saved.

According to a fourth aspect of the present invention, in the information processing apparatus according to any one of the first to third aspects, the information processing apparatus reads an image of a document and forms an image on a sheet. In this case, the same operation and effect as the invention according to any one of claims 1 to 3 can be obtained.

According to a fifth aspect of the present invention, even when margins such as a binding margin and other unnecessary data exist in the image data to be DMA-transferred, the unnecessary image data is extracted and is not stored in the image memory. As a result, the storage capacity of the first storage device can be saved.

According to a sixth aspect of the present invention, in the DMA transfer method of the fifth aspect, the interrupt signal to the CPU is set to D
When inputting MA transfer, the first storage device can be used to start DMA when image data is DMA-transferred and output, so that the productivity of the image processing apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a schematic configuration of a digital copying machine according to an embodiment of the present invention.

FIG. 2 is a timing chart illustrating an image synchronization signal output from an IPU of the digital copying machine.

FIG. 3 is a block diagram illustrating a detailed configuration of a storage unit of the digital copying machine.

FIG. 4 is a block diagram illustrating a detailed configuration of a memory control unit of the storage unit.

FIG. 5 is a block diagram illustrating an image memory of the storage unit.

FIG. 6 is a block diagram illustrating descriptor information used in DMA transfer of the digital copying machine.

FIG. 7 is a block diagram illustrating a configuration of format information of the descriptor information.

FIG. 8 is a flowchart illustrating a process of creating the descriptor information.

FIG. 9 is a flowchart illustrating a DMA transfer process of image data to an image memory using the descriptor information.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Information processing apparatus 2 Image scanner 3 Printer engine 41 DMA controller 51 Second storage device 52 First storage device 53 Descriptor information 58 Interruption instruction data 59 Transfer instruction data

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kiyotaka Mogi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Yasuhiro Hattori 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Ricoh Company (72) Inventor Takao Okamura 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Company (reference) 2C087 AA03 BB10 BC06 BC07 BD41 BD46 2C187 AD03 5B021 AA01 BB02 BB11 CC05 DD12 LD12 5B061 BA02 BA03 CC09 DD09 DD12 5C076 AA36 BA03

Claims (6)

[Claims] 1. An information processing apparatus in which a CPU performs information processing, a first storage device storing target data to be processed, and an input of the target data to the first storage device is performed by one of
Dividing the image data of one image into a plurality of
Descriptor information creating means for creating a plurality of pieces of descriptor information respectively corresponding to the divided portions for performing the DMA transfer independently of the above, and a second storing the created plurality of pieces of descriptor information.
And a DMA controller for sequentially executing the DMA transfer based on the stored plurality of descriptor information, wherein the descriptor information creating means stores, in each of the descriptor information, image data to be transferred at the time of the DMA transfer. The DMA decides whether to discard the data and not transfer the data to the first storage device or to transfer the data to the first storage device as it is.
An information processing apparatus including transfer instruction data for instructing a controller. 2. The method according to claim 1, wherein the descriptor information creation means includes an interrupt signal to the CPU after the end of the DMA transfer based on the descriptor information and before the start of the DMA transfer based on the next descriptor information. 2. An apparatus according to claim 1, further comprising interrupt instruction data for instructing the DMA controller whether to output the data.
An information processing apparatus according to claim 1. 3. The method according to claim 2, wherein the descriptor information creating unit includes: when a margin is provided at a head of the image data in a sub-scanning direction,
The leading descriptor information is created corresponding to the number of lines having the margin width, and the transfer instruction data included in the descriptor information is transferred to the first storage device by discarding image data to be transferred in the DMA transfer. The information processing apparatus according to claim 1, wherein the information processing apparatus does not perform the processing. 4. An image scanner that reads an image of a document and outputs image data, and a printer engine that forms an image on paper based on the image data, wherein the first storage device includes the image scanner and The information processing apparatus according to claim 1, wherein input / output of image data is performed with the printer engine. 5. An information processing device in which a CPU performs information processing, and inputs and outputs the image data to and from a first storage device that stores the image data to be processed.
A DMA transfer method for performing a DMA transfer independently of a PU, wherein input of the image data to the first storage device is 1
The image data of one image is divided into a plurality of
A descriptor information creating step of creating a plurality of pieces of descriptor information respectively corresponding to the divided portions to be performed in the transfer and storing the descriptor information in a second storage device; and performing the DMA transfer based on the stored plurality of pieces of descriptor information. DMA executed by DMA controller sequentially
The descriptor information creating step includes reading and discarding image data to be transferred in the DMA transfer and not transferring the image data to the first storage device, or the first storage device as the descriptor information. To transfer to the DMA
A DMA transfer method including transfer instruction data for instructing a controller. 6. The descriptor information creating step includes, after the end of the DMA transfer based on the descriptor information, an interrupt signal to the CPU before the start of the DMA transfer based on the next descriptor information. 6. An interrupt instruction data for instructing the DMA controller whether to output the data or not is included.
2. The DMA transfer method according to 1.