JPH03237526A - Printing device - Google Patents

Abstract

PURPOSE:To efficiently perform the printing processing by performing the input processing of printing data, whose analysis is necessary among the data inputted from a host equipment by the program processing and performing that of the other data by a hard circuit. CONSTITUTION:When printing data outputted form a host computer 8 is inputted to an interruption/DMA switching circuit 6, a CPU 2 executes the input processing in accordance with the input processing program stored in a control ROM 3. Printing data is read out to the CPU 2 through a data read circuit 9 and a command is analyzed. When printing data is discriminated as a character code, the character code is written in a reception buffer 5. When it is discriminated as command data, it is converted to an intermediate command and is written in the reception buffer 5. When it is discriminated as an image command, the CPU 2 switches the mode from the interruption processing mode to the DMA transfer processing mode to write it in the reception buffer 5 through a DMA transfer circuit 10. Then, the printing processing is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a printing device that prints characters and images according to print data supplied from an external host device such as an LED printer or an LCD printer.

[Conventional technology]

Printing devices such as LED printers and LCD printers are supplied with print data such as character codes and image data necessary for printing processing from an external host device, and perform printing processing on paper or the like based on these data.

Conventionally, two methods have been used for processing when print data as described above is input to a printing device.

First, in the method (-), when print data is supplied to the input section of the printing device, a strobe signal is supplied from the host device at the same time as the output of the print data, and the input section performs an interconnection process from the input section to the CPU (Central Processing Unit) in the printing device. The signal is output, and thereafter the CPU performs print data input control processing according to the print data input processing program stored in the control ROM.

This print data input processing is performed on the print data supplied one byte at a time, and the sequentially input print data is stored in a reception buffer.

On the other hand, another method does not use the above-mentioned processing program, but instead latches the print data output from the host device and then processes the print data using a DMA (direct memory access) circuit. .

[Problems with conventional technology]

The following problems occur in the conventional printing device as described above.

b) When processing received data (print data) by program processing, the data processing speed becomes slow due to the program processing. That is, the input print data may be a character code as described above, or may be image data, and the image data is directly input as dot pattern data. Therefore, in the case of image data, it is possible to automatically write it to the image memory or reception buffer without analyzing the meaning of the data, but it is processed by a program as in the case of character codes and other print control data that require analysis. Since input processing is performed by , the processing steps of the program are large and it takes a long time to process the reception of print data.

On the other hand, when inputting print data using a DMA circuit, the data processing speed is fast because the print data is directly written to the reception buffer by the hardware circuit, but regardless of the content of the input data, a large amount of data is Since the data is mechanically written to the reception buffer, even if printing control data that requires an immediate response is input to the host computer, the corresponding processing cannot be executed immediately and the data cannot be received. Print control data is restricted.

[Purpose of the invention]

In view of the above conventional problems, the present invention provides the content of received data (
It is an object of the present invention to provide a printing device that performs efficient processing depending on the type (type, etc.) and enables input processing of received data in a short time.

[Key points of the invention]

In order to achieve the above object, the present invention provides a printing device that performs a printing operation based on coded print data and image data input from a host device, in which the coded print data is input to a buffer through program processing. a first processing means, a second processing means for inputting the image data into a buffer using a hardware circuit, a determining means for determining whether the data input from the host device is the print data or the image data, and the determining means and switching control means for controlling switching of data input from the host device to the first processing means or the second processing means according to the determination result.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a system configuration diagram of the printing device of this embodiment. In the same figure, the system configuration inside the printing device 21 is
(Central processing unit) 2, control ROM 3, image RAM 4,
Reception buffer 5, interwoven/DMA switching circuit 6
, from the printing section 7, etc. Further, the printing device 1 is connected to a host computer 8, which is an external host device, via the included/DMA switching circuit 6. This host computer 8 is a host device for the printing device 1, and supplies print data such as character codes, image data, printing control data, etc. to the printing device 1 from the host computer 8. Also, when the host computer 8 outputs the above print data, it simultaneously outputs a data strobe signal (DAT).
A 5TB) is output to the printing device 1.

The interlaced/DMA switching circuit 6 is a circuit that performs switching between input processing of print data by program processing, which will be described in detail later, or by DMA processing, depending on whether the print data is a character code or image data.

The CPU 2 controls the printing of the printing device W1 according to the system program stored in the control ROM 3.

For example, by inputting a character code, you can
An interrupt request (I) is sent from the DMA switching circuit 6.
NT RQ) is output to the CPU 2, the CPU 2 inputs a character code to the interwoven/DMA switching circuit 6 via the bus line according to the received data processing program stored in the control ROM 3, as will be described in detail later. The process of writing to the reception buffer 5 is performed via the . The data reading circuit 9 is a circuit that outputs 1 byte of data from the interlaced/DMA switching circuit 6 to the CPU bus when the CPU 2 is under program control.

On the other hand, when the CPU 2 is analyzing the print data output from the host computer 8 under program control and identifies an image data command indicating the transmission of image data, the DMA transfer circuit 10 inputs the print data to the interwoven/DMA switching circuit 6. This circuit directly transfers the image data to the reception buffer 5 by DMA.

Further, this DMA transfer circuit 10 outputs a 1-byte completion signal to the output circuit 11 when it finishes transferring image data for each byte, and when it finishes outputting a preset total number of bytes of image data. Outputs the CPU2 interrupt signal (INT).

Further, the output circuit 11 receives l from the DMA transfer circuit 10.
When a byte end signal is input, or when a 1-byte end signal is input during input processing of print data (character code, etc.) according to the received data processing program of the CPU 2, an acknowledge signal (ACK) is input. Output to host computer 8. This acknowledge signal is a signal that informs the host computer 8 that the input processing of one byte in the printing device 1 has been completed.

Furthermore, when converting the character code written in the reception buffer 5 into dot pattern data, the CPU 2 also performs control such as reading out the character code from the reception buffer 5 and outputting it to a CG (character generator) not shown.

On the other hand, the reception buffer 5 is composed of a predetermined memory area, and in FIG. Indicates that input is via DMA transfer. Furthermore, it shows that a page break intermediate code is input next.

This page break intermediate code will be described later.

Further, the image RAM 4 has a storage capacity of, for example, one page of dot pattern data, and stores one page of dot pattern data converted by the above-mentioned CG. Furthermore, the printing section 7 is a device that prints on paper according to dot pattern data outputted from the image RAM 4 through the video data transfer circuit 12 under the output control of the CPU 2.

The video interface circuit 13 is connected to the CPU 2 and the printing section 7.
This circuit controls the input and output of control signals to and from the

In the printer device configured as described above, the print processing operation will be explained using flowcharts shown in FIGS. 3 and 4, and the like.

First, when the power of the printing device 1 is turned on, initial setting processing of the printing device 1 is executed. In this initial setting process, C
The PU 2 sets the interwired/DMA switching circuit 6 to the interwired side (step (hereinafter referred to as S in FIG. 3) 1).

When the initial setting process is completed, the CPU 2 waits for print data to be input from the host computer 8.

Thereafter, when the print data output from the host computer 8 is input to the interlaced/DMA switching circuit 6, the interlaced/DMA switching circuit 6 sends an interrupt signal INT RQ to the CPU 2.

The CPU 2 receives this and controls R as described above.
Input processing of print data to be input to the included/DMA switching circuit 6 is executed according to the input processing program (interrupt program) stored in the OM3. This input processing is specifically executed according to the flowchart shown in FIG. That is, first, there is a step (1) of reading out the print data input to the interwoven/DMA switching circuit 6 to the CPU 2 via the data reading circuit 9 (hereinafter referred to as ST in FIG. 4), and then analysis of the command (ST2).
), If it is determined by this analysis that the input print data is a character code, for example, this character code is written into the reception buffer 5 (Sr3). In addition, if it is command data (print information data), the input command is converted into an intermediate command for performing the corresponding processing in the printing device 1 and written to the reception buffer 5 (Sr1.5T5).
.

By repeating the above process, the data input state of the reception buffer 5 in FIG.
C. Command intermediate codes are written sequentially. However, each print data is interwoven/D for each byte.
This is input to the MA switching circuit 6. That is,
Each time the input of each character code and intermediate command to the reception buffer 5 is completed, the output circuit 11 outputs a hair removal signal to the host computer 8 according to the 1-byte end signal from the CPU 2 (5T9), and then the next signal output from the host computer 8. character codes or command data are sequentially input into the reception buffer 5 and written into the buffer 5 sequentially.

When the CPU 2 sequentially analyzes commands through program processing as described above, if the analyzed command is determined to be an image command, the CPU 2 changes the data input processing from the interwoven processing mode according to the program to DMA transfer processing. Execute the process to switch to the mode.

Specifically, this image command is data having the structure shown in FIG. 5, and is composed of an image display command to indicate that the data to be sent thereafter is image data, and data indicating the total number of bytes of the image. The data of the total number of image bytes is data indicating the total number of bytes of subsequent image data. When this image command is input, the CPU 2 sets the total number of bytes of image data included in the image command in the count circuit in the interlaced/DMA switching circuit 6, and further sets the total number of bytes of image data included in the image command in the DMA transfer circuit 10 via the interwoven/DMA switching circuit 6. The image data write start address A in the reception buffer 5 is set in the data transfer destination address register.

Thereafter, the CPU 2 sets the included/DMA switching circuit 6 to the DMA transfer processing mode (Sr7). That is, as a result of this processing, the data for the total number of bytes inputted from the host computer thereafter will not be inputted according to the control program by the CPU 2.

Therefore, the CPU 2 is freed from data input processing and can perform other processing.

Further, after determining the input of the image command, the CPU 2 writes an image command intermediate code indicating that image data will be written in the subsequent area into the reception buffer 5 (Sr8).

After performing the above processing, the image data output from the host computer 8 is directly output to the reception buffer 5 via the DMA transfer circuit 10 without being read from the interlaced/DMA switching circuit 6 to the CPU 2.

During the 1-byte transfer processing period by the DMA transfer circuit 10, the CPU 2 is instructed to output a DMA request (DMA RQ,) signal to the CPU 2 to keep the CPU bus open so that the CPU 2 does not perform access operations at the same time. do. Then, image data is sequentially written one byte at a time from the initial address A of the DMA transfer area in the reception buffer 5.

During this time, the 1-byte end signal is also sent to the DMA transfer circuit 10.
An acknowledge signal is output every time the image data is supplied to the output circuit 11, and then new image data is sequentially output to the interlaced/DMA switching circuit 6.

The input processing of image data to the reception buffer 5 continues as described above, and when the input data transfer processing for the total number of bytes of image data set previously is completed, the DMA transfer circuit 10 outputs a CPU 2 interrupt signal and transfers the image data to the CPU 2. Informs you that data entry is complete. C.P.
In response to the input of this interwoven signal, U2 performs the interwoven processing shown in FIG.
Return to input processing according to the program from M3 (step (STP) 1).

In addition, as described above, while the device data constituted by the host computer 8 is being supplied to the receiving buffer 5, the CPU 2 converts this command into an intermediate command when a page break command is input as print data, and then sends it to the receiving buffer 5.
Write this page break intermediate command in .

After the print data is written to the reception buffer 5 in the predetermined format as described above, the CPU 2 writes the print data to the reception buffer 5.
The data written in is read out and drawing data is created in the image RAM 4.

That is, the CPU 2 sequentially reads data from the reception buffer 5 and analyzes the commands (52, S3). For example, if the read data is a character code, it is converted into corresponding dot pattern data using CG (not shown) as described above. and writes it into the image RAM 4 (S4). Further, if the read data is command data, corresponding command processing is performed (S5). Furthermore, if the read data is image data, the image data is written into the image RAM 4 (S6). Further, if the read data is a page break command, printing processing is performed (S7).

This printing process transfers the dot pattern data written to the image RAM 4 as described above to the video data transfer circuit 1.
2 to the printing section 7, and the printing section 7 writes the tone pattern data on the paper.

As described above, in this embodiment, print data is sent to the receiving buffer 5.
When inputting data into DM, image data that does not require content analysis and other print data such as character codes that require analysis such as code discrimination are processed separately.
By using the A transfer process and by inputting print data such as character codes to the receiving buffer through program processing, efficient processing can be performed and the input processing of received data can be performed in a short time.

In the above embodiment, image data was used as an example of print data that does not require analysis, but the present invention is not limited to this. For example, font download data input from a host computer can also be input by the present invention. Can be processed.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to efficiently input print data from a host device, and to input received data in a short time. Therefore, printing processing in the printing device can be performed efficiently.

[Brief explanation of drawings]

Fig. 1 is a system block diagram of a printing device according to an embodiment, Fig. 2 is a constituent country of the receiving buffer 1, and Figs. 3 and 4 are print data input processing operations and print output of a printing device according to an embodiment. FIG. 5 is a flowchart illustrating the processing operation; FIG. 5 is a diagram illustrating the structure of an image command; FIG. 6 is a flowchart illustrating the processing when an interlaced signal is input. 1...Printing device, 2...CPU. 3... system@ROM. 4... Image RAM. 5... Receive buffer, 6... Interwoven/DMA switching circuit, printing section, host computer, data reading circuit, DMA transfer circuit, output circuit.

Claims (1)

[Scope of Claims] In a printing device that performs a printing operation based on print data that requires analysis and print data that does not require analysis input from a host device, the print data that requires analysis is stored in a buffer by program processing. a first processing means for inputting data; a second processing means for inputting data that does not require the analysis into a buffer using a hardware circuit; and analyzing whether the data input from the host device is print data that requires the analysis. a discriminating means for discriminating whether print data is unnecessary; and a switching control means for controlling switching of data input from the host device to the first processing means or the second processing means according to the discrimination result of the discriminating means. A printing device comprising: