JPS60214035A - Printer interface device - Google Patents

Abstract

PURPOSE:To connect a video terminal completely different in code system to a printer by providing a rewritable code conversion table in the interface circuit of the printer. CONSTITUTION:The video terminal 1 and printer 9 are connected together through the interface circuit 17. This interface circuit 17 has a communication control circuit 12, code converting means 13, buffer memory 14, and CPU15. The code converting means 13 has the conversion table and a signal sent from the video terminal 1 is converted on the basis of the conversion table and supplied to the printer 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printer interface device that can be connected to a multi-gradation scan type video terminal having an arbitrary code system to print images.

In recent years, with the advent of printers capable of color printing (for example, thermal printers), printers that are connected to a color video terminal and print the same image as the displayed image in color have become widely used.

FIG. 1 is a diagram 1172 showing a typical configuration example of the video terminal. In this figure, video terminal 1 has dot data for one screen (one dot data is 8
The frame memory 2 stores the dot data (bits), and the dot data supplied from the frame memory 2 is stored in red, green (G),
Blue (B) A color information generation circuit 3 having a conversion table for converting into digital RGB signals (8 bits each) and a D/A converter (digital/analog) for converting these digital RGB signals into analog RGB signals. (converter) 4, and a CRT display device 5 for displaying an image of analog RGB signals.

In order to intercept the data (received or signal) from this video terminal 1 and perform color printing on the printer, (a) the output of the frame memory 2 (8-bit dot data), and (b) the output of the color information generation circuit 3. Output (24-bit digital RGB signal), Output of G-e''D/person converter 4 (analog RGB (8
) must be transmitted to the printer.

In this case, the four-strand method (b) requires a large number of signal bits to be sent, and the method (c) provides a wide signal band and is equipped with a high-speed, high-precision A>D converter on the printer side. The drawback is that it must be made from wheat.

Therefore, the method (a) is widely used, but in this case, the configuration shown in FIG. 2 was conventionally used.

That is, the dot data outputted from the frame memory 2 is supplied to the printer 9 via an 8-bit transmission line 6t-7, which has a configuration and operation valve similar to that of the color information generation circuit 3, and color printing is performed. was.

Therefore, in the conventional configuration described above, depending on the specifications of the video terminal 1 and the printer 9, a situation may arise in which the conversion rule of the code converter 7 has to be changed, and the connection between the video terminal 1 and the printer 9 may be changed. It wasn't easy.

In view of the above circumstances, the present invention provides a printer interface 7/8 device that can be directly connected to a video terminal having an arbitrary code system and perform color printing, and can be rewritten in the printer's interface circuit. a code converting means, forming a conversion table in the code converting means based on the conversion code sent from the video terminal, and converting the signal sent from the video terminal based on the conversion table. Features.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 3 shows a printer interface 7 according to an embodiment of the present invention.
FIG. 2 is a block diagram showing the configuration of main parts of the Ace device. In this figure, reference numeral 11 denotes a transmission line for exchanging signals with the video terminal 1, which is based on the standard 7800C interface.

12 is a communication control circuit that controls the exchange of signals. In this case, the communication control circuit 12
When the hereday/signal READY Th is sent, the video terminal 1 sends 1 byte of data D and the strobe signal STB in parallel. When the communication control circuit 12 receives the strobe signal 5TBt, it reads the data D,
Returns an acknowledge ACK. In this way, the data D is received by the communication control circuit 12 in 1-byte units, and is stored in the RAM 13 (
The data is written to the backup memory 14 via the code conversion means). There are two types of received data DK: a conversion code, which will be described later, and dot data sent from the frame memory 2.

The RAM 13 stores a conversion table group 13a (see FIG. 4) that performs all code conversions of received data D.
8 consists of a byte medium-high speed static RAM, and the address terminals AO to A7 of the RAM 13 are connected to the communication control circuit 1.
2, AO to A12 are connected to the address bus of the C'PU 15, and data terminals DO-D7 are connected to the data bus 16.

The received data D supplied from the communication control circuit 12 to the address terminals AO to A7 is code-converted by the conversion daple group 13a and becomes data Da at the data terminals DO to D.
7 and the data Da is written to the backup memory 14. In this case, address ends A8 to A12 are CP
Controlled by UI 5, the value of 88 to A12 is "0".

Each time the number changes to "1", "2", "3", etc., conversion tables A, R, G, B, etc. are selected, and conversion is performed using these conversion tables. Here, address 24n of conversion table A (n=0. 1. 2...
・The value n is written in 255) so that when conversion table A is selected, the input and output of the RAM 13 match. In addition, the conversion tables R, G, and B are
Similar to the conversion table of the color information generation circuit 3 shown in FIG.
The contents of the conversion tables R, G, and B, which output signals, can be rewritten from CPUI 5, and the contents of the conversion tables R, G, and
The contents of B are imported based on the conversion code sent from video terminal 1. In this embodiment, it is possible to form 2I1=32 conversion tables by changing the values 8 to A12 at the address end. Further, the above components 12 to 16 constitute a printer interface circuit 17, which is installed within the printer.

Next, the operation of this embodiment will be explained. The operation of this embodiment is as follows:
Based on the conversion code sent from video terminal 1,
The initial set stage of forming conversion tables R9G and Be in the RAM 13 and the dot data sent from the frame memory 2 of the video terminal 1]) a
(digital RGB signal) and backup memory 14
and writing the print data set to. below,
These operations will be explained in order.

Tl+ initial set.

When the power switch or reset switch (both not shown) of the printer 9 is pressed down, the CPU 15 performs initial reset in the following procedure.

■ Perform conversion table human writing. That is, the values "1", "2", "6", etc. are set at the first address, second address, third address, etc. of the conversion table A. This means that when translation table A is selected, RA
This is to match the input and output of M13.

■ Keep conversion table A selected and turn on signal RE.
ADY is activated to notify the video terminal 1 that reception preparations have been completed.

■ After the video terminal l transmits a command indicating ``I will now send the conversion code,'' it transmits the conversion code one byte at a time. This conversion code is the first
The code is the same as the conversion table code of the color information generation circuit 3 shown in the figure, and each dot data contains 3 bytes (G, B
(compatible with each color).

(2) The CPU 15 writes the sent conversion code to the backup memory 14. In this case, since conversion table A is selected and the input and output of RAMI 3 match, the conversion code is written into buffer memory 14 as is.

■ When all the conversion codes have been sent, the video terminal 1 sends a command indicating that ``transmission of the conversion codes is now complete.''

■ Upon receiving this command, the CPU 15 sends the signal RE
ADY'ft is set to high level to stop the transmission of the video terminal 1, and the conversion code written in the backup memory 14 is read out and sequentially written to conversion tables R, G, and B. In this case, it is also possible to write the converted code while performing desired conversion. For example, R2O.

B The conversion code for each color is C (cyan), M (magenta),
It is also possible to write by replacing each conversion code KW of Y (yellow).

(2) Print/print data set.

When the creation of conversion tables R, G, and B is completed, the CPU
15 selects the conversion table R and makes the signal READY active again. As a result, the video terminal 1 sequentially reads out the dot data from the frame memory 2 and transmits them to the communication control circuit 12. When the communication control circuit 12 supplies the received dot data to the iRAM 13, the dot data is code-converted by the conversion table R and written to the backup memory 14 as data Da. In this way, the dot data in the 7-frame memory 2 is read out → transmitted → received → code converted → written into the buffer memory 14 in units of bytes. Once the data Da for one screen is stored in the buffer memory 14, it is supplied to the printer 9 and dot printing is performed. Below, conversion tables G and B
A similar operation is performed for color printing.

According to this embodiment, any conversion table can be formed in the RAM 13, so that all the video terminals 1 and printers 9 having completely different code systems can be connected.

Further, the video terminal 1 does not need to convert data according to the specifications of the printer 9 and send it. Furthermore, since subtle color adjustments can be made, color reproducibility is excellent.

Application examples of this embodiment include the following.

(2) By writing the conversion code directly into the RAM 13 independently of the printer, it is possible to cause the printer 9 to print an image whose color is different from that of the CR1 display device 5 (FIG. 1).

■ JIS code → ASCII code, JIS code →
Any code conversion such as conversion to EBCDI C code can be performed and printed.

- Multiple conversion tables can be assigned to each color of Y, M, and C, increasing the degree of freedom of the device. Also, for characters,
It is also possible to have separate conversion tables for graphics.

As described above, in the present invention, a rewritable code conversion table is provided in the interface circuit of the printer, so that a video terminal having a completely different code system can be connected to the printer. Furthermore, the video terminal is freed from the inconvenience of having to convert and send data according to printer specifications. Additionally, it allows for fine color adjustments, resulting in excellent color reproducibility.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a conventional video terminal, FIG. 2 is a block diagram showing an example of a connection between a conventional video terminal and a printer, and FIG. 3 is a block diagram showing the configuration of a main part of an embodiment of the present invention. The block diagram shown in FIG. 4 is a conceptual diagram showing the structure of the conversion table group 13& provided in the RAM 13. 1...Video terminal, 9...Printer, 13...RAM (code conversion means), 13a
...Conversion table group, 17...Interface circuit. Applicant Shinko Electric Co., Ltd.

Claims (1)

[Claims] The printer receives a signal sent from a video terminal via an interface circuit and prints based on this signal, and has a rewritable code conversion means in the ink face circuit, A printer/interface device, characterized in that a conversion table is formed in the code conversion means based on a conversion code sent from the terminal, and a signal sent from the video terminal is converted based on this conversion table.