JPH1091365A - Printer controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer controller which can print an image without disturbing a part of image and also can evade an increase in cost even when the image data size is larger or smaller than the form size by holding the line width of the image data to obtain the head address of the next line and stopping temporarily the DMA transfer when the head address is matched with the value of an address counter. SOLUTION: The image data to be printed are expanded into a main memory 101, and the head address of the image data is set at an address register 111. At the same time, the line width of the main scan direction of the image data is set at a line register 112. Then the value of the register 112 is added to the register 111 simultaneously with the DMA transfer and the address of the next line head address is obtained. The value of an address counter 110 is compared with the next line head address held by the register 111. When they are matched with each other, it means that the DMA transfer is over. Thus, the DMA transfer is temporarily stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer control device for outputting image data developed on a main memory to a printer that does not perform DMA transfer.

[0002]

2. Description of the Related Art Conventionally, in a printer control device for sequentially reading image data developed on a main memory and outputting the image data to a printer, it is possible to force printing even when the image data and the paper size do not match. is there. That is, the case where the printer has only paper of a size smaller than the size of the image data, or conversely, the case where the image size is much smaller than the paper size. It is necessary to be able to determine what image data has been printed, even when printing is performed in a state where the paper size does not match.

Here, when printing on a sheet of paper smaller than the size of the image data, for example, the image data is printed with the upper left corner coincident with the upper left corner of the sheet (see FIG. 4).

In this case, as a method of printing the image data so that the image data can be discriminated, a method of reducing the image data to a paper size and printing the entire image, or a method in which only a portion of the image data cut out by the paper size is used as it is. A method of printing in a state is adopted. The method of reducing the paper size is cumbersome and the processing time is long. On the other hand, the method of printing only the paper size portion as it is has simple processing and a short processing time.

Here, a conventional example in which only the paper size portion of the image data is printed as it is will be described.
In order to print the image as it is without disturbing, it is necessary to process the invalid data of the line so as not to be used for the printing and to print the valid data of the next line.

In order to determine whether the data is valid data or invalid data, for example, Japanese Patent Application Laid-Open No. Hei 4-83674 discloses a method in which a print size is held by a counter and data that runs off the paper is not output to a printer.

In the "printer control device" disclosed in Japanese Patent Application Laid-Open No. 7-9708, a DMA control device in the printer control device includes a counter unit for counting the amount of untransferred data for each line of image data. After the printing of the paper width of each line is completed, the address for DMA transfer is changed by the value of the counter section, and the head address is moved to a position that jumps over the data exceeding the paper width to restart the DMA. Then, at the end of the printing of the paper width, the image data buffered in the FIFO in the printer control device is erased by the FIFO clear, so that in the DMA transfer on the next line, the data that can fit in the paper width is transferred.

[0008] On the other hand, when printing on paper of a size much larger than the size of the image data (see FIG. 6),
Since the synchronization signal in the main scanning direction remains active even after one line of image data has been output from the FIFO, it is necessary to control not to output the data of the next line during this period. For this reason, conventionally, a line counter for holding the line size of the image data is provided,
Each time the MA transfer is performed, the countdown is performed so that data larger than the size of the image data is not output.

[0009]

However, in the prior art as disclosed in the above-mentioned Japanese Patent Application Laid-Open Nos. 7-9708 and 7-9708, a data size counter and a line size counter are used. Therefore, when the resolution of the printer increases or the paper size becomes large, the amount of data occupying one line becomes enormous, and a very large counter is required to count the data. As a result, the cost increases. There was a problem that would be invited.

In order to cope with both the case where the image size is larger than the paper size and the case where the image size is smaller than the paper size, it is necessary to provide separate counters for each. However, there is a problem that the cost is increased here as well.

The present invention has been made in view of the above, and a printer control device for reading image data from a main memory, outputting the image data to a printer, and printing the data.
It is an object of the present invention to enable printing without disturbing a part of an image even if the size of the image data is larger or smaller than the paper size, and to realize the cost without increasing the cost.

[0012]

According to a first aspect of the present invention, there is provided a printer control apparatus for reading out image data developed on a main memory line by line and outputting data to a printer. A temporary control means for temporarily storing image data DMA-transferred from the main memory; a memory control means for controlling writing of data to the temporary storage means and erasure of data; Output control means for outputting data from the means to the printer in a format and timing suitable for printing, an address register for storing a DMA transfer start address, an address counter for counting addresses for each DMA transfer, and a line width. The line register to be held, and the address An address changing unit for changing the value of the register, a control unit for obtaining the start address of the next line using the line register, and suspending the DMA transfer when the address counter matches the start address of the next line. And control means.

That is, the line width of the image data is held, the head address of the next line is obtained, and the DMA transfer is temporarily stopped when the value of the address counter matches, so that data output according to the paper width can be performed. Since image disturbance can be eliminated and a large-scale image data size can be avoided, cost can be reduced.

According to a second aspect of the present invention, in the printer control apparatus, the DMA control means includes a page counter for holding the number of lines for one page, and the DMA control means is provided for each line.
When the A transfer is completed, the page counter is counted down, and when the transfer of one page of image data from the main memory is completed, the DMA transfer is completed.

That is, by holding the number of lines for one page and decrementing each time the head address of the line is obtained, the cost can be reduced because a large-scale image data size counter is not used. .

According to a third aspect of the present invention, in the printer control device, when the image data stored in the temporary storage unit is larger than the sheet width, the memory control unit may change the image data of the sheet width. After the data is output, the data in the temporary storage unit is erased. If the image data stored in the temporary storage unit is smaller than the paper width, as soon as the data in the temporary storage unit becomes empty, the D in the next line becomes empty.
It requests the start of MA transfer and performs writing to the temporary storage means.

That is, if invalid data exists in the temporary storage means, it is erased and stored from the head image data of the next line. If all data of one line is output and becomes empty, the next line is immediately deleted. By starting the DMA transfer of data, print output can be performed without disturbing the image even when the image data is larger or smaller than the paper size.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a printer control device according to the present invention will be described in detail with reference to the accompanying drawings.

[Embodiment] (Structure of Embodiment) FIG. 1 is a block diagram showing a system structure using a printer control device according to an embodiment. In FIG. 1, the printer control device includes a main memory 101 for developing and storing image data on a system bus 100, a CPU 102, and a printer I for transferring the image data developed on the main memory 101 by DMA.
/ F device 103 and a printer device 104.

The printer I / F device 103 is provided with a DM
DMA control unit 105 as A control means, and FIFO unit 1 as temporary storage means for temporarily storing image data
06, read / write to / from FIFO unit 106 and FIFO
A FIFO control unit 107 as a memory control unit for controlling the erasure of data in the unit 106, and an output as an output control unit for outputting data from the FIFO unit 106 to the printer device 104 in a format and timing suitable for printing. And a control unit 108.

Further, the DMA control unit 105 includes a control unit 109 as control means, an address counter 110 for counting addresses for each DMA transfer, an address register 111 for holding a head address of one line, and a line width. And a page counter 114 that counts down each time the value of the address counter 110 matches the start address of the next line.

(Operation of the Embodiment) Next, the operation of the printer control device configured as described above will be described.
Here, a case in which image data is read from the main memory and transferred in the order of increasing addresses will be described.

In FIG. 1, first, the main memory 101
Expand the image data to be printed on top. Next, the head address of the developed image data is
This is set in the address register 111 in the DMA control unit 105. In the line register 112, the data amount (line width) of the image data in the main scanning direction is set.

By giving the start of image output to the printer controller, a print request is issued to the CPU 102.
To the printer I / F device 103. In the printer I / F device 103, before outputting a print start signal to the printer device 104, the FIFO unit 1
A DMA transfer is started in order to put data at 06 first.

Next, a method of generating a DMA address will be described with reference to FIGS. FIG. 2 is an explanatory diagram showing a method of generating a DMA address, and FIG.
5 is a flowchart showing the control operation of the first embodiment. In FIG. 2, reference numeral 201 denotes the head address of the image data;
2 is the start address of the next line, and 203 is image data.

In FIG. 3, first, in step S301, the values of an address register 111, a line register 112, and a page counter 114 are set in response to a print request from the CPU 102. Subsequently, step S30
In step 2, the head address 201 of the image data is loaded into the address counter 110, the DMA transfer of the image data from the main memory 101 is started, and at the same time, the value of the line register 112 is added to the address register 111.
The start address 202 of the next line is obtained.

When a certain amount of data (half full or the like) is input to the FIFO unit 106, the DMA transfer is temporarily stopped. A synchronization signal (lgate_ / fgate) output according to the print timing of the printer device 104
_ Signal, etc.), the data is read from the FIFO unit 106, the output control unit 108 changes the print format of the printer device 104, and outputs it. Note that lgate_ is a main scanning direction synchronization (horizontal synchronization) signal, and fgate_ is a sub-scanning direction synchronization (vertical synchronization) signal.

At step S304, the address counter 11
The DMA address in 0 is added every one transfer cycle of the bus. In step S305, the address counter 1
The value of 10 is compared with the start address 202 of the next line held in the address register 111.

If the values match in step S305, 1
The process proceeds to step S306 to indicate that the DMA transfer for the line has been completed, and the DMA transfer is temporarily stopped. On the other hand, if there is no match in step S305,
It returns to step S303.

If the size of the image data is larger than the paper size, before the value of the address counter 110 matches the value of the address register 111 in step S303, the lgate_ signal becomes High and the print output of one line is completed. In this case, when the lgate_ signal changes from Low to High, step S is immediately performed.
Proceeding to 306, the DMA transfer is stopped.

Next, in step S307, the page counter 114 is counted down to indicate the number of untransferred lines.
Further, it is determined in step S308 whether or not the page counter 114 is 0. If it is not 0, the process returns to step S302 to start the DMA transfer of the next line. On the other hand, if it is determined in step S308 that the value is 0, the DMA transfer is terminated to indicate that the transfer of the image data for one page has been completed.

(Operation Example 1) Here, the operation when the image data is larger than the paper size will be described.

FIG. 4 is an explanatory diagram showing an operation when the image data is larger than the paper size, FIG. 5 is a timing chart showing an operation example 1 of the printer control device, and FIG. 8 is a state transition diagram of the printer control device.

In FIG. 4, reference numeral 401 denotes valid data to be actually printed, 402 denotes invalid data prepared in the memory but not actually printed, 403 denotes invalid data in the FIFO unit 106, and 404 denotes invalid data in the memory. , 405 is the line width of the image data, 406 is the first address of the first line, 407 is the first address of the second line, 408
Is the start address of the third line, 409 is the end address of valid data, and 410 is the address of invalid data.

Reference numeral 501 shown in FIG. 5 denotes an operation state of the printer control device. Further, in FIG. 8, reference numeral 801 denotes a state [DMA] during DMA transfer and no FIFO output is performed, and 802 denotes a state during DMA transfer.
And the state of the FIFO output [DMA & PRIN
T], 803 is a state [CLEA] in which no DMA transfer is performed during FIFO clear and no FIFO output is performed.
R], 804 is a state [PRINT] in which the FIFO is being output and no DMA transfer is performed.

The lgate_ / fgate_ signal is output when the printer device 104 detects the size of the sheet, and indicates an effective printing area when each signal is low.
The output to the printer device 104 is such that the fgate_ signal is L
This is performed when the signal is low and the lgate_ signal is low. Also, when the lgate_ signal becomes High, printing on one line is completed.

Lgate When the signal becomes low, the state [DMA] 801 changes to the state [DMA & PRIN].
[T] 802, and starts output to the printer device 104 (timing T1).

Further, the state [DMA & PRINT] 8
When the lgate_ signal becomes High in 02, the state is transited to [CLEAR] 803, and the output control unit 108 stops outputting to the printer device 104 (timing T2).

At the timing T2, the data up to the data at the address 409 (the data at the end of the valid data 401) is printed on the paper, and the data thereafter becomes the invalid data 402.
In this case, assuming that the address counter 110 performs the DMA transfer by counting up to the address 410 of the invalid data, the invalid data 402 is the same as the invalid data 403 already transferred in the FIFO unit 106 and the invalid data 403 in the memory not yet transferred. And invalid data 404 remaining.

Here, by clearing the FIFO unit 106 in the state [CLEAR] 803, the FIFO unit 106
Invalid data in is erased.

Upon completion of the FIFO clearing, the state transits to the state [DMA] 801 (timing T3), and the DMA
In the control unit 105, the start address 406 of the next line is transferred from the address register 111 to the address counter 110, and at the same time, the value of the line register 112 is added to the value of the address register to obtain the start address 408 of the next line.

The DMA transfer starts when the value is set in the address counter 110, and the lgate_ signal becomes Lo.
w, the output control unit 108
Output to 4 starts.

Therefore, the main memory 10
Skip invalid data in 1 and D of valid data in the next line
MA transfer can be initiated. Hereinafter, similarly, an image without disturbance can be printed on the second and subsequent lines.

(Operation Example 2) Here, the operation when the image data is smaller than the paper size will be described.

FIG. 6 is an explanatory diagram showing an operation when the image data is smaller than the paper size, FIG. 7 is a timing chart showing an operation example 2 of the printer control device, and FIG. 8 is a state transition diagram of the printer control device.

In FIG. 6, reference numeral 601 denotes a line width of image data, 602 denotes a non-printing area in one line,
603 is the paper width, 604 is the first address of the first line,
605 is the start address of the second line, 606 is the start address of the third line, and 607 is the last address of the image data. Reference numeral 701 shown in FIG. 7 denotes a state indicating an operation state of the printer control device.

The lgate_ / fgate_ signal is output when the printer device 104 detects the size of the sheet, and indicates an effective printing area when each signal is low.
The output to the printer device 104 is such that the fgate_ signal is L
This is performed when the signal is low and the lgate_ signal is low. Also, when the lgate_ signal becomes High, printing on one line is completed.

Lgate When the signal becomes low, the state [DMA] 801 changes to the state [DMA & PRIN].
[T] 802, and starts output to the printer device 104 (timing T4).

Since the size of the image data is small, l
gate Before the signal becomes High, the address counter 110 counts the start address 605 of the next line. When the control unit 109 in the DMA control unit 105 detects that the values of the address counter 110 and the address register 111 match, the control unit 109 stops counting up the address counter 110. In addition, the FIFO control unit 107
The writing to the unit 106 is stopped.

D before the lgate_ signal goes high
Since the MA transfer is completed, the state is [PRINT] 8
04 (timing T5). FIFO section 10
6 stores data up to the address 607.

The data of the address 607 is stored in the FIFO 10
6 and the state transits to the state [DMA] 801 when the FIFO unit 106 becomes empty (timing T6). At this time, in the DMA control unit 105, the start address 605 of the next line is transferred from the address register 111 to the address counter 110, and at the same time, the value of the line register 112 is added to the value of the address register 111. Ask.

Then, the DMA transfer starts from the time when the value of the address counter 110 is set. Also, lgat
Reading from the FIFO unit 106 is started from the point in time when the e_ signal changes from High to Low (timing T7).

As a result, the DMA transfer of the next line can be performed without outputting to the non-printing area of the sheet. In the same manner, an image without disturbance can be printed after the second run.

[0054]

As described above, according to the printer controller of the present invention (claim 1), the head address of the next line is obtained while maintaining the line width of the image data, and the value of the address counter matches. By temporarily stopping the DMA transfer at the point of time, data output according to the paper width can be performed, so that image disturbance can be eliminated and a large-scale image data size can be avoided, thereby reducing costs. be able to.

Further, according to the printer control apparatus of the present invention, the number of lines for one page is held and decremented every time the head address of the line is obtained. Since a size counter is not used, the cost can be reduced.

According to the printer control device of the present invention, when invalid data is present in the temporary storage means, it is deleted and stored from the first image data of the next line, and the data of one line is stored. Is output, the DMA transfer of the data of the next line is started immediately. Therefore, when the image data is larger than the paper size,
Even in a small case, print output can be performed without disturbing the image.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration using a printer control device according to an embodiment.

FIG. 2 is an explanatory diagram showing a method of generating a DMA address according to the embodiment;

FIG. 3 is a flowchart showing a control operation of a DMA control unit shown in FIG.

FIG. 4 is an explanatory diagram showing an operation when image data according to an operation example 1 is larger than a sheet size.

FIG. 5 is a timing chart illustrating an operation example 1 of the printer control device.

FIG. 6 is an explanatory diagram illustrating an operation when image data according to an operation example 2 is larger than a sheet size.

FIG. 7 is a timing chart illustrating an operation example 1 of the printer control device.

FIG. 8 is a state transition diagram of the printer control device according to the embodiment.

[Explanation of symbols]

 101 Main Memory 103 Printer I / F Device 104 Printer Device 105 DMA Control Unit 106 FIFO Unit 107 FIFO Control Unit 108 Output Control Unit 109 Control Unit 110 Address Counter 111 Address Register 112 Line Register 113 Address Change Unit 114 Page Counter

Claims (3)

[Claims] 1. A printer control device for reading out image data developed on a main memory line by line and controlling data output to a printer, a temporary storage means for temporarily storing image data DMA-transferred from the main memory. Memory control means for controlling writing and erasing of data in the temporary storage means, output control means for outputting data from the temporary storage means to a printer in a format and timing suitable for printing, and DMA transfer Address register for storing the start address of each line, an address counter for counting addresses for each DMA transfer, a line register for holding a line width, an address changing unit for changing the value of the address register using the value of the line register, Use the register to set the start address of the next line. And a DMA controller configured to suspend DMA transfer when the address counter matches the next line head address. 2. The system according to claim 1, wherein the DMA control means includes a page counter for holding the number of lines for one page. When the DMA transfer is completed for each line, the page counter is counted down, and one page from the main memory is deleted. 2. The printer control device according to claim 1, wherein the DMA transfer is terminated when the transfer of the image data for the minute is completed. 3. If the image data stored in the temporary storage means is larger than the paper width, the memory control means erases the data in the temporary storage means after outputting the image data of the paper width. If the image data stored in the temporary storage means is smaller than the paper width, as soon as the data in the temporary storage means becomes empty, a request to start DMA transfer of the next line is issued to the temporary storage means. The printer control device according to claim 1, wherein writing is performed.