JPH022170B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling a ring buffer of an output device, and more particularly to a method for controlling a ring buffer that outputs data page by page.

[Conventional technology]

BACKGROUND ART Printing devices are widely used that store data sent line by line from a central processing unit in a data buffer, and when one page's worth of data is accumulated in the data buffer, print is triggered by this. This printing apparatus employs a ring buffer having a capacity for n pages, since the processing speed is slow when outputting data with consecutive pages.

In a printing device using this ring buffer, data management of the ring buffer is important. On the other hand, conventional printing apparatuses employ a method in which, when inputting data to a ring buffer, an output pointer is used to check the empty area of the ring buffer, and data is input into the empty area. However, if for some reason data input is overtaken, such as data input being input into an area that is not an empty area, the printing device will print random data. Moreover, this printing continues thereafter, causing problems in that errors occur in the output print data.

[Problem that the invention seeks to solve]

In view of the above-mentioned conventional situation, the present invention provides a ring buffer control method that manages overtaking of input data based on the page management information, particularly for storing page management information in the ring buffer, and improves the reliability of output data. This is an attempt to improve sexual quality.

[Means for solving problems]

In order to solve the above-mentioned problems, this invention stores data sent line by line in a ring buffer having a capacity of n pages, and outputs page by page from this ring buffer. A ring buffer management method includes a page management unit that manages pages of data stored in a ring buffer, and a writing unit that writes page information to the ring buffer, and controls input and output of the ring buffer based on page information of the ring buffer. It is done by hand.

[Effect]

The above-mentioned ring buffer has page information written together with data, and controls the input/output of data to the ring buffer based on this page information to improve page management accuracy and manage overtaking. This improves reliability.

〔Example〕

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

FIG. 1 is a block diagram of essential parts of an embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the present invention. The central processing unit 1 sends character data line by line to the printing device 2. The printing device 2 receives this character data in the register 21 and sends it to the ring buffer 2.
Transfer character data to 2. The page management section 23 manages the character data input to the ring buffer on a page-by-page basis, and sends a signal to the page information writing section 24 for each page.

The page information writing unit 24 stores write information at the first address of the data. Written information, e.g. page number
221 is information that is not printed during printing.

The input/output data control unit 25 includes a ring buffer 2
Input/output is controlled based on the page number 221 of 2.

The above control operation will be explained with reference to FIG.
When the printing device 2 receives character data from the central processing unit 1, it performs initial settings. Condition (1) shown in Figure 2. Hereinafter, the states in FIG. 2 will be indicated by numbers in parentheses. In this initial setting, page number #1 of the write information described above is stored at the leading address of the ring buffer.

Character data is read from the register 21 and stored in the ring buffer 22 (3). This continues until the input character data is stored for one page, and the page management unit 23 confirms that the storage for one page has been completed.
(Four). When the storage of one page is completed, the page information writing unit 24 operates and writes the next page information, that is, #2, to the ring buffer 22 (5). Furthermore, the page management unit 23 writes the character data to the ring buffer 22. It is detected whether full-page writing has been performed (6), and it is also detected whether input of character data has been completed (7). When the entire writing is completed or input data is completed, the input/output control section 25 outputs page by page from the ring buffer (8), and the page management section 23 inputs character data page by page.

The above explanation was made using a printing device, but 1.
Needless to say, the present invention can be applied to display devices that display character data on a screen-by-screen basis without any problems.

〔Effect of the invention〕

Now, as can be understood from the above explanation, in short, the present invention writes page information to the ring buffer, manages the ring buffer based on this page information, and detects the occurrence of overtaking by the disturbance of the page information. The present invention is highly effective in obtaining normal output data.

[Brief explanation of drawings]

FIG. 1 is a block diagram of essential parts of an embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the present invention. In the figure, 1 is a central processing unit, 2 is a printing device, 22 is a ring buffer, 23 is a page management unit, 2
4 indicates a page information writing section.

Claims (1)

[Claims] 1. In an output device that stores data sent line by line in a ring buffer having a capacity of n pages and outputs page by page from the ring buffer, page management for managing pages of data stored in the ring buffer in the output device. 1. A control method for a ring buffer, comprising: a writing section for writing page information into the ring buffer, and controlling input/output of the ring buffer based on page information of the ring buffer.