JPH06295281A - Print controller - Google Patents

Abstract

PURPOSE:To print image data whose size is larger than the size of a DMA space with respect to the print controller which transfers image data on a memory to a printer by DMA to print it after mapping the image data in the DMA space on a virtual memory. CONSTITUTION:A mapping means 2 is controlled by a mapping control means 6 to successively map unmapped image data in the idle area of the DMA space, thus forming blocks. At this time, the end of the mapping processing of a just preceding block is reported before the completion of transfer of the block by a mapping end report means 8 to determine the size of each block. Respective formed blocks are successively transferred by a DMA control means 3; and when transfer of one block is completed, a DMA relay means 9 starts transfer of the next block and the mapping control means 6 maps the next block after unmapping the block whose transfer is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print controller for reading image data from a memory and outputting it to a printer.

[0002]

2. Description of the Related Art In order to read image data from a memory and output it to a printer, there is a method of performing a DMA (Direct Memory Access) transfer by virtual addressing. In that case, it is necessary to map the image data in the memory into a space (hereinafter, referred to as “DMA space”) in which the DMA can be performed in the virtual memory.

FIG. 7 is a block diagram showing an outline of a conventional print control device. In FIG. 7, 1 is a memory, 2
Is a mapping means, 3 is a DMA control means, 4 is a printer, and 5 is an image information storage means. In memory 1,
Image data to be printed is expanded. The image data on the memory 1 is not necessarily physically expanded in a continuous area, but can be virtually processed by the mapping means 2. further,
The mapping means 2 converts the image data into D on the virtual memory.
DMA transfer is performed after remapping in the MA space.
The DMA control unit 3 DMA-transfers the data expanded in the DMA space to the printer 4. Image information storage means 5
Stores image information such as the size of image data and supplies it to the mapping means 2.

Incidentally, as a conventional document related to such a print control device, there is, for example, "interface"'92 .1.

[0005]

[Problems to be Solved by the Invention]

(Problem) However, in the above-mentioned conventional technique, when the size of the image data per sheet becomes enormous and exceeds the size of the DMA space, the image data for one sheet is changed at one time. There is a problem that the image data cannot be printed because it cannot be mapped in the DMA space.

(Explanation of Problems) When the DMA transfer is performed using the DMA space as described above, the image data to be transferred cannot be transferred unless it actually exists in the memory 1. Moreover, the entire space of the memory 1 cannot be used only for transferring image data. Therefore, the size of the DMA space is limited to a size smaller than the size of the memory 1.

By the way, conventionally, since the data amount of image data for one sheet was not so large, it was possible to map it in the DMA space at one time. However, in recent years, due to colorization and high resolution of printers, the size of image data per sheet becomes enormous and exceeds the size of DMA space. DMA at once
There are cases where it becomes impossible to map to space.

A possible solution to this problem is to divide the image data into a plurality of blocks and perform mapping and transfer in a plurality of times. However, in order to transfer one block and then the next block, the DMA space is unmapped and then the next block is mapped and then transferred. Therefore, there is a delay between transfers. Will occur. Therefore, it is necessary to provide a memory on the printer side or change the printer operation such that the printing operation is temporarily stopped.

On the other hand, in the DMA transfer method by physical addressing, as a method for transferring a large amount of data without interruption, the memory is divided into a plurality of blocks, the blocks are transferred, and the data is written into the blocks after the transfer. A method is adopted in which the transfer is continuously carried out while simultaneously performing the above and the same (Japanese Patent Publication No. 61-32710 and Japanese Patent Application Laid-Open No. 61-288252). However, in the method of performing DMA transfer by virtual addressing, there is no method for transferring a large amount of data without interruption. An object of the present invention is to solve the above problems.

[0010]

In order to solve the above problems, according to the present invention, the image data expanded on the memory is mapped to the DMA space on the virtual memory by the mapping means, and then the printer is controlled by the DMA control means. In a print control device that performs DMA transfer to and prints
Unmapped image data is sequentially mapped to the empty area of the DMA space to form a block.
Mapping control means for controlling the mapping means so as to unmap the transferred blocks each time the transfer of one block is completed, and block ordering means for designating the transfer order of the blocks formed by the mapping means,
A mapping end notifying means for notifying the mapping control means of the end of the mapping processing of the block before the completion of the transfer of the immediately preceding block, and the transfer of the next block is started in accordance with the transfer order each time the transfer of one block is completed. A DMA relay means for instructing the DMA control means is provided.

[0011]

[Operation] The mapping control unit controls the mapping unit to sequentially map the unmapped image data to the empty area of the DMA space to form a block. At that time, the size of each block is determined by notifying the mapping control unit of the end of the mapping process of the block by the mapping end notifying unit before the transfer of the immediately preceding block is completed. The blocks formed by the mapping means have the transfer order designated by the block ordering means. When the DMA control means completes the transfer of one block, the mapping control means controls the mapping means to unmap the transferred block. Further, the DMA relay means instructs the DMA control means to start the transfer of the next block according to the transfer order.

In this way, when the size of the image data per sheet becomes enormous and exceeds the size of the DMA space, the image data for one sheet is divided into a plurality of blocks, Each block is mapped in the DMA space and the block transfer is relayed. As a result, continuous transfer becomes possible, and it becomes possible to print image data of a size exceeding the size of the DMA space without making a change such as providing a memory on the printer side.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the outline of the print control apparatus of the present invention. The reference numerals correspond to those in FIG. 7, 6 is a mapping control means, 7 is a block ordering means, 8 is a mapping end notifying means, and 9 is a DMA relay means. Image data to be printed is expanded in the memory 1. The mapping means 2 stores one page of image data on the memory 1 (a minimum unit of mapping, usually 2K).
It is mapped to the DMA space on the virtual memory for each (about byte). Image information such as data size is stored in the image information storage means 5.

FIG. 2 is a diagram showing the relationship between the image data and the DMA space. In FIG. 2A, the image data is D
FIG. 2B shows a case where the image data is smaller than the MA space and can be mapped to the DMA space at one time, and FIG. 2B shows a case where the image data is larger than the DMA space and cannot be mapped to the DMA space at one time. There is. As in the case of FIG. 2A, it is not necessary to divide the image data when the mapping is possible at one time, but when it is impossible to perform the mapping at one time as in the case of FIG. , It is necessary to divide the image data into multiple blocks and transfer.

The division of the image data into a plurality of blocks is performed while the image data on the memory 1 is mapped in the DMA space by the mapping means 2. That is, during mapping, mapping is terminated by the notification from the mapping end notifying means 8 to form one block, then mapping is started again and the mapping is terminated by the next notification from the mapping end notifying means 8. To form the next block. By repeating such processing, the image data is divided into a plurality of blocks.

The divided blocks are ordered by the block ordering means 7 in accordance with the data transfer direction. For example, in the case of double-sided printing, when printing on the front surface of the paper, since the image data is transferred from the beginning, the blocks are also ordered from the beginning. However, when printing on the back side of the paper, since the image data is transferred from the end, the blocks are also ordered from the end.

When the DMA transfer of one block is completed, the mapping control means 6 unmaps the block to make the DMA space reusable, and
The mapping means 2 is controlled so that the first block of the unmapped blocks is mapped therein. The operation of the mapping control means 6 will be described with reference to the drawings.

FIG. 3 is a diagram showing an operation example of the mapping control means. The image data is expanded in the memory 1 as shown in FIG. First, as shown in FIG. 3B, mapping of the head portion of the image data is started, and when a mapping end notification is issued from the mapping end notification means 8, the mapping is ended and a block A is formed. Subsequently, the DMA control unit 3 starts the transfer of the first block A, but at the same time, the mapping control unit 6 starts the mapping of the remaining image data, and as shown in FIG. Block B is formed in the same manner as A.

When the transfer of the block A is completed, the DMA control means 3 starts the transfer of the block B, and the mapping control means 6 unmaps the block A. Then, the mapping of the remaining image data is started in the empty area generated by the unmapping, and the block C is formed as shown in FIG. When the transfer of the block B is completed, the DMA control unit 3 starts the transfer of the block C, and the mapping control unit 6 unmaps the block B. Then, the mapping of the remaining image data is started in the empty area generated by the unmapping, and the block D is formed as shown in FIG.

Next, when the transfer of the block C is completed, the transfer of the block D is started and the block C is unmapped. When the block C is unmapped, there is no remaining image data to be mapped, so D
As shown in FIG. 3 (f), only the block D remains in the MA space, and when the block D is unmapped after the transfer of the block D is completed, there is no data in the DMA space.

Next, the DMA relay means 9 will be described. Whenever the transfer of one block is completed, the DMA relay means 9 controls the DMA control means 3 so as to continuously transfer the next ordered block, and transfers all the image data to the printer 4. . FIG. 4 is a block diagram showing an example of the configuration of the DMA relay means and the DMA relay-related portion of the DMA control means. The reference numerals correspond to those in FIG. 1, 31 is a transfer completion notifying means, 32 is an address register, 33 is a count register, 91 is an information exchanging means, and 92 and 93 are block information holding sections.

In the DMA relay means 9, the block information holding unit 9 stores block information indicating the start address and data size of the block currently being transferred and the block to be transferred next.
It is held at 2,93. When the transfer completion notifying means 31 of the DMA control means 3 notifies the completion of the transfer of one block, the information exchanging means 91 holds the contents of the address register 32 and the count register 33 and the block information of the next block. The information in the block information holding unit 93 is instantly replaced so that the DMA transfer of the next block can be continuously executed. By thus operating the DMA relay means 9, the DMA control means 3 continuously starts the transfer of the next block when the transfer of one block is completed, and when the transfer is completed, transfers the next block. Transfer all image data continuously, such as start.

Next, the mapping end notifying means 8 will be described. The mapping end notifying means 8 has a transfer order of 1
It is necessary to notify the end of mapping before the completion of the transfer of the immediately preceding block, and the following methods can be mentioned as the method. (1) When the mapping time reaches a predetermined value, the end of mapping is notified. (2) When the amount of mapped data reaches a predetermined value, the end of mapping is notified. (3) When predetermined information is obtained from the printer, for example, when the fed paper reaches a predetermined position, the end of mapping is notified. (4) When the mapping time per unit data amount reaches a predetermined value, the end of mapping is notified. (5) When the remaining data amount of the block being transferred reaches a predetermined value, the end of mapping is notified.

Next, each of the above methods (1) to (5) will be described. (1) A notification of the end of mapping when the mapping time reaches a predetermined value. FIG. 5 is a block diagram showing an example of the mapping end notifying means. Reference numerals correspond to those in FIG. 1, 81 is a reference value generating unit, 82 is a comparator, and 83 is a timer. In the reference value generation unit 81, a time shorter than the DMA transfer time of the block of the minimum size is preset as a reference value, and the comparator 82 measures the reference value and the time after the start of mapping for each block. When the value of the timer 83 reaches the reference value, the comparator 8
2 notifies the mapping control means 6 of the end of the mapping process. According to this method, when the lower limit of the DMA transfer time per block is known, the reference value is set to be less than that, so that the mapping can be surely performed before the completion of the transfer of the block immediately before the transfer order. The end of can be notified.

(2) A notification of the end of mapping when the amount of mapped data reaches a predetermined value. In this method, mapping control means 6 performs mapping while counting the size (for example, the number of bytes) of mapped data, and mapping end notifying means 8 compares the count value with a reference value to obtain a count value. Reaches the reference value, it notifies the mapping control means 6 of the end of the mapping process. The reference value is set to a value such that the mapping time is shorter than the transfer time of a block having a size corresponding to that value.
Then, the value may be a constant value or may be decreased as the number of blocks increases. According to this method, a block having a designated size can be formed.

(3) Notifying the end of mapping when predetermined information is obtained from the printer, for example, when the fed paper reaches a predetermined position. According to this method, the printer 4 monitors the paper position during printing, outputs a detection signal each time the paper passes a predetermined position, and the mapping end notifying means 8 receives the detection signal, and the mapping control means. 6 is notified of the end of the mapping process. According to this method, the paper passage detection position is set slightly before the position corresponding to the print amount of data for one block, so that the completion of mapping is reliably notified before the transfer of the immediately preceding block is completed. can do.

(4) A notification of the end of mapping when the mapping time per unit data amount reaches a predetermined value. First, the relationship between the remaining amount of DMA space and the required mapping time per page will be described. FIG. 6 is a diagram showing the relationship between the remaining space in the DMA space and the mapping required time per page. The horizontal axis indicates the remaining amount of DMA space,
The vertical axis represents the mapping required time per page. As shown in FIG. 6, when the remaining amount (free area) of the DMA space is large, the minimum data unit of mapping is 1
It takes a short time to map the data for one page, but when the remaining amount of the DMA space is small, the time required for mapping the data for one page becomes long. If this relationship is used, the remaining amount of DMA space can be known by monitoring the mapping required time per page.

This method uses this relationship to determine the end point of mapping. That is, the mapping control means 6 constantly measures the mapping required time per page during mapping, and the mapping end notifying means 8 compares the measured value with the reference value,
When the measured value falls below the reference value (hatched area in Figure 6),
The mapping control means 6 is notified of the end of the mapping process. According to this method, when the mapping process is likely to take a long time, the mapping process can be stopped and the next block can be formed. However, since this method alone cannot output the mapping end notification in association with the transfer completion time point of the immediately preceding block, when this method is adopted, the above (1) to (3) are used.
It is necessary to use it in combination with any of the above methods.

(5) A notification of the end of mapping when the remaining data amount of the block being transferred reaches a predetermined value. In this method, the DMA control unit 3 counts the remaining data amount of the block being transferred, and the mapping end notifying unit 8 compares the count value with the reference value, and the count value becomes equal to or less than the reference value. At this time, the mapping control means 6 is notified of the end of the mapping process.
According to this method, the next block can be reliably formed before the transfer of the immediately preceding block is completed. However, in this method, when forming the first block, there is no block before it, and therefore, since the transfer of the previous block has not been performed, only when forming the first block,
Other methods need to be adopted.

Note that each of the above-exemplified methods can be adopted independently, or can be combined with other methods. Including this, which method should be adopted may be the most suitable one according to the situation such as the content of image data.

[0031]

As described above, according to the print control apparatus of the present invention, even if the size of the image data per sheet becomes enormous and exceeds the size of the DMA space, one sheet of paper is enough. Image data is divided into a plurality of blocks, each block is mapped in the DMA space, and the block transfer is relayed. As a result, it is possible to continuously transfer a plurality of blocks, and it is possible to print the image data having a size exceeding the size of the DMA space without making a change such as providing a memory on the printer side. Further, since each block is automatically formed while being mapped by the mapping end notifying means, it is not necessary to set the size of each block in consideration of the size of the DMA space and the image data in advance. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a print control apparatus of the present invention.

FIG. 2 is a diagram showing a relationship between image data and a DMA space.

FIG. 3 is a diagram showing an operation example of mapping control means.

FIG. 4 is a block diagram showing an example of a configuration of a DMA relay unit and a DMA relay-related portion of a DMA control unit.

FIG. 5 is a block diagram showing an example of mapping end notification means.

FIG. 6 is a diagram showing the relationship between the remaining amount of DMA space and the required mapping time per page.

FIG. 7 is a block diagram showing an outline of a conventional print control device.

[Explanation of symbols]

1 ... Memory, 2 ... Mapping means, 3 ... DMA control means, 4 ... Printer, 5 ... Image information storage means, 6 ... Mapping control means, 7 ... Block ordering means, 8 ... Mapping end notifying means, 9 ... DMA relay Means, 31 ... Transfer completion notifying means, 32 ... Address register, 33 ... Count register, 81 ... Reference value generating unit, 82 ... Comparator, 8
3 ... Timer, 91 ... Information replacing means, 92, 93 ... Block information holding unit

Claims (1)

[Claims] 1. A print control apparatus for mapping image data expanded on a memory to a DMA space on a virtual memory by a mapping means, and then DMA-transferring to a printer by the DMA control means for printing.
Unmapped image data is sequentially mapped to the empty area of the DMA space to form a block.
Mapping control means for controlling the mapping means so as to unmap the transferred blocks each time the transfer of one block is completed, and block ordering means for designating the transfer order of the blocks formed by the mapping means,
A mapping end notifying means for notifying the mapping control means of the end of the mapping processing of the block before the completion of the transfer of the immediately preceding block, and the transfer of the next block is started in accordance with the transfer order each time the transfer of one block is completed. A print control device comprising: a DMA relay unit for instructing the DMA control unit.