JPS61232488A - Address conversion for real brightness conversion table - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an address conversion method for an actual brightness conversion table built into a CRT display device [Prior Art] A CRT display device having a conventional actual brightness conversion table is constructed as shown in FIG.

That is, in FIG. 4, reference numeral 1 denotes an arithmetic processing unit such as a host computer, which sends and receives data to and from a screen memory 3 and an actual brightness conversion table 4 via an interface circuit 2.

The screen memory 3 is constituted by a refresh memory that stores display color codes corresponding to the screen, and normally a data format with a positive or negative sign is used as the data format per dot.

The display color code read out from the screen memory 3 by a timing signal output from the timing generation circuit 5 in synchronization with the scanning of the CRT display 8, which will be described later, is inputted to the actual brightness conversion table 4 via the data line 6. Ru.

The data converted into actual brightness using the actual brightness conversion table 4 is converted into a video signal by the D/A converter 7 and displayed on the display screen of the CRT display 8.

By the way, due to the increase in the capacity of today's memory elements and the enhancement of screen memory input devices, the bit width B1 of the display color code per dot in the screen memory 3 shown in FIG. 4 tends to become wider (generally 12 bits). ~16 bits). However, the input bits of the actual brightness conversion table 4 in FIG.
Since the screen memory 3 cannot be made so large, its bit width B2 is generally about 8 bits. Therefore, in order to match the output bits of the screen memo 'J3 to the input bits of the actual brightness conversion table 4, it is necessary to adjust the data width.

Generally, a barrel shifter or the like is known as a data width adjustment circuit that performs such data width adjustment.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional actual brightness conversion table, when data in which positive and negative values can be specified by sign pick (a) is input to the barrel shifter without address conversion, as shown in FIG. 5(a), - to (-1) (
When the value of F F F F) is shifted by 1 bit in hexadecimal, the result (-1) is (+
1) (0oo1 in hexadecimal) is different from the result (0) when the value is shifted by 1 bit, and there is a problem in that the input data to the actual brightness conversion table circuit is inconvenient.

Further, assuming that the actual brightness conversion table 4 has contents showing the relationship between the display color code and the actual brightness as shown in FIG. To write to table 4 continuously, 'a
How to start an address from “o o o” and “000
Two methods of starting an address are known: one method of starting the address from 0'';

However, in the case of the former method, there is a problem in that in order to write to the actual brightness conversion table, a technique is required to change the starting point of the address once at an intermediate address change point AP, as shown in Fig. 6). In addition, in the case of the latter method, in order to write to the actual brightness conversion table, the sixth
As shown in Figure (C), there is a problem in that a technique is required to change the actual brightness data once at the data change point DP in the middle, and either method is difficult to convert the actual brightness data from the arithmetic processing unit 1 to the actual brightness conversion table 4. It is necessary to perform complicated operations when loading actual brightness data.

Therefore, the present invention provides a method for adjusting the data width of input data and the input data width of the actual brightness conversion table in an actual brightness conversion table for a CRT display where the input data format can specify positive and negative values. This eliminates the inconvenience of not being able to shift negative values when adding an adjustment circuit, and when loading actual brightness data from the arithmetic processing unit to the actual brightness conversion tool 7', it is possible to change the address point and change the actual brightness. It is an object of the present invention to provide an address conversion method for an actual brightness conversion table that does not require a data point change operation.

[Means for solving problems]

In order to achieve the above object, the present invention provides a real brightness conversion table for a CRT display in which an input data formatter can specify positive and negative values, in which all address input data to the real brightness conversion table are A shift circuit that shifts to the value of is inserted, and the shift output of the shift circuit is supplied to the actual brightness conversion table via a data width adjustment circuit, thereby converting the address of the actual brightness conversion table. It is characterized by

[Effect]

The present invention provides an actual brightness conversion table for a CRT display in which the format of data per dot in the screen memory can specify positive or negative values, and in order to adjust the input data width of the actual brightness conversion table, When a data width adjustment circuit such as a barrel shift circuit is added, the input data (display color code) input to the data width adjustment circuit can be changed to a negative value by, for example, inverting the sign bit in the input data using a shift circuit. Even if you shift the input data to a positive value and convert the address, and shift (-1), the result is (0
), and when loading the actual brightness data from the arithmetic processing unit into the actual brightness conversion table, the memory area in the actual brightness conversion table is shifted to a positive address. This enables loading at consecutive addresses from address "0000" to the final address as seen from the device.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of the present invention.

First, the configuration will be explained. In the figure, 1 is an arithmetic processing unit such as a host computer, 2 is an interface circuit, 3 is a screen memory, 4 is an actual brightness conversion table, 5 is a timing generation circuit, 6 is a data output line, 7 is a D/A converter, 8 is CRT
It's a display.

The screen memory 3 stores a screen-compatible one that is configured in a format consisting of a code bit a and 4-bit hexadecimal data b.
A required number of dot data (display color code) C is stored.

The display color code stored in the screen memory 3 is output from the timing circuit 5 based on the command from the arithmetic processing unit 1.
It is read out in response to a timing signal synchronized with the scanning of the T-display 8 and is supplied to the address selector 10 via the data output line 6.

This address selector 10 separates the code bit (a) and data (b) from the input data supplied thereto, and outputs them respectively.

On the other hand, when loading actual luminance data from the arithmetic processing unit 1, the address selector 10 is supplied with its write address from the interface circuit 2 via the address bus 1), and a write control signal is supplied via the control bus 12. will be supplied.

Data b output from address selector 10 is directly supplied to barrel shifter 13 as a data width adjustment circuit, and sign bit a is supplied to one input end of exclusive OR circuit 14 as a shift circuit. The write control signal is supplied to the other input side of this exclusive OR circuit 14, and the output of this exclusive OR circuit 14 is supplied to the barrel shifter 13.

The input data whose data width has been adjusted by the barrel shifter 13 is then supplied to the actual brightness conversion table 4 as address data. On the other hand, the actual luminance data is supplied to the actual luminance conversion table 4 via the interface circuit 2 and the write data line 15 when the actual luminance data is loaded from the arithmetic processing device 1 . - Then, the actual luminance data read from the actual luminance conversion table 4 is converted into an analog signal by the D/A converter 7, and this is supplied to the CRT display 8 as a video signal,
Display data is displayed on the display screen.

Next, the operation of this embodiment will be explained. Now screen memory 3
To explain the case where the display color code stored in the screen memory 3 is read out and input into the actual brightness conversion table 4, the display color code C read out from the screen memory 3 is inputted into the code bit a and the address data b by the address selector 10. The sign bit a is supplied to one input side of the exclusive OR circuit 14. This exclusive OR circuit 4 is supplied with a write control signal having a logic value of "1" from the arithmetic processing unit 1 via the interface circuit 2 and the write control line 12. When the sign bit a in the data read from the screen memory 3 from the summation circuit 14 is positive, that is, "0", the logic value is "1", and when the sign bit a is negative, that is, "1", the logic value is "O". , and output inverted bits obtained by inverting the sign bit a.

By inverting the sign bit a in this way, as shown in FIG.
aooo”~”FFFF” and positive value “0000”
~ The data width of “7FFF” is a positive value “ooooo”
” to “FFFF” and can be converted to only positive values.

Therefore, since the inverted bit output from the exclusive OR circuit 14 is supplied to the barrel shifter 13, when shifting data with this barrel shifter 13, (-1
) is no longer inconvenient that it becomes (-1) even if shifted, the data width can be adjusted accurately, and the adjusted data is supplied to the actuality conversion table 4. The address space of this actual luminance conversion table 4 is, as shown in FIG. 3, a memory area M2 in which negative values in the memory area M in the conventional example are shifted to positive values, Therefore, in the actual brightness conversion table 4, the screen memory 3
Actual brightness data corresponding to the display color code read out from the CRT display 8 is selected, converted into a video signal by the D/A converter 7, and supplied to the CRT display 8, where dots are displayed at a predetermined brightness on the display screen. Ru.

On the other hand, when loading actual luminance data from the processing unit I into the actual luminance conversion table 4, the actual luminance conversion table 4 becomes the memory area M2 in which negative values are shifted to positive values as described above. Therefore, the addresses of the real brightness conversion table 4 appear to be continuous addresses starting from "0000" from the arithmetic processing unit 1, and by controlling the write control signal to a logical value of "0", the real brightness corresponding to the positive address can be changed. Data can be continuously loaded into the actual brightness conversion table 4.

In the above embodiment, a case has been described in which an exclusive OR circuit is applied to invert the sign bit in address data, but it goes without saying that other sign inverting circuits may be applied.

Further, in the above embodiment, a case has been described in which the barrel shifter 13 is applied as the data width adjustment circuit, but the present invention is not limited to this, and other data width adjustment circuits may be applied.

〔Effect of the invention〕

As explained above, according to the present invention, the shift circuit inverts the sign bit of the input data input to the actual brightness conversion table, thereby shifting positive and negative input data to only positive values. Therefore, it is possible to prevent data shift errors when inserting a data width adjustment circuit for adjusting the bit width between the screen memory and the actual brightness conversion table, and it is possible to perform reliable data width adjustment. , when loading the actual brightness data from the arithmetic processing unit into the actual brightness conversion table, the actual brightness data can be loaded from the arithmetic processing unit as consecutive positive addresses, and the address point changing operation in the arithmetic processing unit; This has the effect of eliminating the need for changing data points.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the data width used for detailed explanation of the invention, and FIG. 3 is an explanatory diagram showing the memory space of the actual brightness conversion table. Figure 4 is a block diagram showing a conventional example, Figure 5 (
a) and (bl are explanatory diagrams showing shift images, respectively, and Fig. 6fa), (b) and (C) are explanatory diagrams showing the relationship between input color code and actual brightness in the conventional example, respectively, and memory map images. FIG. 2 is an explanatory diagram showing an actual luminance graph image. In the figure, ■ is the arithmetic processing unit, 2 is the interface circuit, and 3 is the arithmetic processing unit.
is a screen memory, 4 is an actual brightness conversion table, 7 is a D/A converter, 8 is a CRT display, 10 is an address selector, 12 is a write signal line, 13 is a barrel shifter, 14
is an exclusive OR circuit.

Claims (2)

[Claims] (1) In an actual brightness conversion table for a CRT display in which the input data format can specify positive or negative values, a shift circuit is inserted to shift all address input data to the actual brightness conversion table to positive values. , an address of an actual luminance conversion table is characterized in that the address of the actual luminance conversion table is converted by supplying the shift output of the shift circuit to the actual luminance conversion table via a data width adjustment circuit. Conversion method. (2) An address conversion method for an actual brightness conversion table according to claim 1, wherein the actual brightness data is loaded into the actual brightness conversion table at consecutive positive addresses.