JPH06227092A - Control method of print data output - Google Patents

Abstract

PURPOSE:To improve performance by a method wherein a print data output is ensured and a weight from a CPU (data processing unit) upon read/write is reduced. CONSTITUTION:A CPU 10 is connected to a first RAM 12 by selectors 14, 15 when the bit-map of n-th page is produced in a first RAM 12 while a DMAC 11 is connected to a second RAM 13 by the CPU 10. When the bit map production is finished, CPU 10 is connected to the second RAM 13 by selectors 14, 15 and the DMAC 11 is connected to the first RAM 12 while the DMAC 11 starts DMA output from the first RAM 12. Under this condition, the CPU 10 becomes unable to access a bit map data on the n-th page.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print data output control method applied to a printer unit such as a laser printer or a digital copying machine.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a RAM access portion in a conventional print data output controller. 1 is a CPU (central processing unit) which is a data processing unit, and 2 is a direct memory access (Direct Memor
y Access) controller (DMAC), 3 is an arbiter (arbiter) for arbitrating (adjusting) CPU access and DMAC access, and 4 is a RAM (random access memory).

The CPU 1 develops the image data of an arbitrary unit (page or section) from the host computer in the RAM 4 as a bit map, and when this processing is completed, the DMAC 2 starts the DMA output from the RAM 4. The arbiter 3 is necessary for the CPU 1 to create the bitmap of the next page or section while outputting the data expanded in this bitmap.

[0004]

In the configuration of the prior art described above, when the DMAC 2 is outputting a bitmap, the C
When PU1 tries to access RAM4, DMAC
One cycle of 2 accesses is waited for. This slows down the speed. Conversely, CP
If the DMAC2 tries to access while the U1 is accessing, the DMAC2 is kept waiting. As a result, not only the performance deteriorates, but also when the speed of the printer engine becomes faster, the DMA may not be in time and the printing may not be performed correctly.

The present invention has been made in view of the above points, and it is possible to improve the performance by ensuring the output of print data and reducing the weight at the time of reading / writing from the data processing unit. It is an object of the present invention to provide a print data output control method that can be performed.

[0006]

To achieve the above object, the present invention relates to a print data output control method for expanding image data received from a higher-level device into a bitmap and outputting the bitmap, when printing with a bitmap. When printing any page or section
It is characterized in that the data processing unit cannot access the page or section.

Further, when printing an arbitrary page or section, the data processing section starts generation of a bitmap of the next page or section.

An arbitrary page or section,
The address of the next page or section is the same for the data processing unit.

[0009]

According to the above-mentioned means, since the data processing unit such as the CPU cannot access the page or section while printing an arbitrary page or section, the output of the data expanded in the bit map can be ensured. Moreover, the weight at the time of reading / writing from the CPU is reduced, and the processing efficiency and processing performance are improved.

The data processing unit cannot access the page or section when a bitmap is created and printing of the page or section is started. However, since the data processing unit generates a bitmap of the next page or section, the processing efficiency is improved. Is improved.

Further, for the data processing unit, since the address of each page or section is the same, the processing efficiency is further improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an example of a controller for carrying out an embodiment of the print data output control method of the present invention, and 10 is a data processing unit C
PU, 11 is a DMA controller (DMAC), 12 and 13 are a first RAM and a second RAM, 14 is a first selector for selecting whether the CPU 10 accesses the first RAM 12 or the second RAM 13, and 15 is a DMAC 11 for the first RAM 12 or the second RAM 13. A second selector for selecting which of the two RAMs 13 is to be accessed, 16 is the first selector 14 or the second selector
It is a control circuit that controls which of 15 is selected.

In the controller, based on the image data received from the host computer or the like which is a higher-level device, the CPU 10 sets the bitmap of the nth page to the first R
When making to AM12, CPU10 is the first RAM in the control circuit 16
Two selectors 14 and 15 are set so that 12 and DMAC 11 are connected to the second RAM 13. When the bitmap of the nth page is completed, it is transmitted from the CPU 10 to the control circuit 16 and the DMAC 11, and the control circuit 16 causes the CPU 10 to generate the second
The two selectors 14 and 15 are reset so that the DMAC 11 is connected to the RAM 13 and the DMAC 11 is connected to the first RAM 12.
11 starts DMA output from the first RAM 12. The CPU 10 cannot access the n-th page bitmap data, and starts to create the (n + 1) -th page bitmap data.

When the DMA output is completed, the DMAC 11 informs the CPU 10 and the control circuit 16 that the DMA output is completed. When the CPU 10 finishes creating the (n + 2) th page bitmap data, the CPU 10 informs the control circuit 16 and the DMAC 11 that the bitmap has been completed. The control circuit 16 determines the CPU 10 based on these two pieces of information.
To the first RAM 12 and the DMAC 11 to the second RAM 13 so that the two selectors 14 and 15 are reset.

Since the CPU 10 does not need to select the two RAMs 12 and 13, the address of the nth page, the address of the (n + 1) th page and the address of the (n + 2) th page are the same for the CPU 10.

In the above embodiment, the bit map target is a page unit (full bit map), but the same operation is performed even if the target is a section (partial bit map).

According to the print data output control method by the controller described above, the CPU 10 cannot access the page or section at the time of the DMA output for the page or section, that is, at the time of printing by the printer engine (not shown). That is, when the data of a certain page or section is being sent to the printer engine, the CPU 10 cannot access the RAMs 12 and 13 in which the data is written, so that the output by the DMA can be made reliable and the CP
Data processing performance is improved by reducing the wait when reading / writing from U10. It is also expected to improve print performance when printing with partial bitmaps.

[0019]

As described above, according to the print data output control method of the present invention, according to the method of claim 1,
Since the access of the data processing unit is considered to be proper, the output of the data expanded in the bitmap is ensured, and the read / write weight from the data processing unit is reduced, so that the processing efficiency and the processing performance are improved. be able to.

According to the method of claim 2, the bitmap of the next page or section can be efficiently generated.

According to the method of claim 3, since the address of each page or section is the same for the data processing section, the data processing can be performed more efficiently.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an example of a controller for carrying out an embodiment of a print data output control method of the present invention.

FIG. 2 is a block diagram showing a RAM access portion in a conventional print data output controller.

[Explanation of symbols]

10 ... CPU (data processing unit), 11 ... DMAC (direct memory access controller), 12, 13 ... R
AM, 14, 15 ... Selector, 16 ... Control circuit.

Claims (3)

[Claims] 1. A print data output control method for expanding image data received from a higher-level device into a bitmap and outputting the bitmap, when printing with a bitmap, when printing an arbitrary page or section,
A print data output control method, wherein the data processing unit cannot access the page or section. 2. The print data output control method according to claim 1, wherein when printing an arbitrary page or section, the data processing unit starts generating a bitmap of the next page or section. 3. The print data output control method according to claim 2, wherein the address of an arbitrary page or section and the address of the next page or section are the same for the data processing unit.