JPS6392995A - Lookup table buffer apparatus for display - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides a table (hereinafter referred to as a lookup table) for converting image data from an image memory such as a graph ink display 41g into color information. , relates to a look-up table buffer device for a display, which includes a look-up table buffer provided separately for processor access.

[Essentials of the invention]

The present invention provides a display device equipped with an image memory and a lookup table for converting image data from the image memory into color information, in which a lookup table buffer is rewritten for processor access to the lookup table under the control of a control circuit. It is designed to reduce the load of writing to the lookup table on the processor and to enable the preparation of multiple types of lookup table contents.

[Conventional technology]

Conventionally, in graphic display devices, the third
As shown in the figure, in order to increase the number of colors that can be displayed, the output data 1a of the image memory 1 is not directly converted into a color signal 3a, but is converted into D/
It was converted into a color signal 2a via the A converter 3.

Here, if the information IIn bit from the image memory l is the address information \U of the lookup table memory, and the data length of the lookup table memory is m bits, then
It was possible to simultaneously display 2″ colors from a 2m package.

[Problem that the invention seeks to solve]

In the conventional technology, since this lookup table 2 is placed between the image memory 1 and the D/A converter 3, when the pronocenosa 5 attempts to write the lookup table 2, bus arbitration (adjustment) is not performed. It becomes a problem. In this arbitration, the processor 5 side is allowed to access the vertical retrace section of the display 4 in order to eliminate flickering of the image.

Therefore, the load on the processor 5 was heavy. Also, if you want to have several lookup tables 2 and switch them at high speed, you can divide the RAM used for this table 2 into several banks, but if you have a resolution of 1280 x 1024 dots or more and a 60Hz non-ink In order to realize a lathe (non-interlaced scanning) display, this RA
M is required to be readable at high speed, and there is a problem in that it is difficult to provide a large amount of M.

[Means for solving problems]

In order to solve the conventional problems, the present invention consists of a lookup table buffer that can be freely accessed by a processor, and a control unit that controls data transfer between the lookup table buffer and the lookup table. It is now possible to prepare multiple types of uptable contents.

[Effect]

In the display lookup table buffer device configured as described above, the processor freely writes to the lookup table buffer, and then the control section sends a transfer start signal and blanking start signal (vertical retrace start signal). ), ■ Transfer from the lookup table buffer to the lookup table at high speed during blanking. At this time, the control unit sends ;t to the lookup table and lookup table buffer.
Generates and serves the all-tall signal.

The control unit also manages banks of the lookup table buffer, and can transfer the contents of desired banks.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.
In the figure, in order to write data to lookup table 1, processor 5 first writes data to bank O of lookup table buffer 6 from processor data bus 15 via selector S2 and bus 16. Next, the processor 5 starts the transfer using the signal 26 from the processor. Here, this transfer start signal 26 is synchronized with the blanking start signal 25 and controlled? It becomes a signal 20 via the ffD circuit 10.

By setting the clear terminal CL of the D Frisop front panel 8 to a "low" level using No. 8 20, the clear state of the counter 9 is removed, and the contents of the counter 9 are increased by the applied clock 21. At this time , in the control circuit IO, the signal 22.17 switches selectors S9 and S2 for transfer from the lookup table buffer 6 to the lookup table 2 so that the signal flows from the bus 16 to the bus 14, and the signal 13.24 is switched. When the contents of the counter 9 match the transfer end address, a clear signal 1 of the counter 9 is generated by the counter END signal 18.
Activate 9. In this way, the transfer of the contents of bank 0 of lookup table buffer 6 to lookup table 2 is completed.

Next, if you want to transfer the contents of bank 1, specify bank 7 to the control circuit 10 by signal 24,
All you have to do is start the transfer.

Unlike the embodiment in FIG. 2, if each lookup table buffer 7 is configured independently, the processor can access a bank that is not being transferred even during a transfer.

〔Effect of the invention〕

As described above, the present invention has the following effects: first, it reduces the load on the processor when writing to the lookup table; it also allows for the preparation of several types of lookup table contents, and facilitates their exchange.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a look-up table batza device for display according to the present invention and its peripheral circuitry, and FIG. 2 is a detailed block diagram of a preferred embodiment of the present invention.
FIG. 3 is a block diagram of a conventional display lookup table and its peripheral circuitry. l... Image memory 1a... Image data 2... Lookup table 2a... Color information 3... D/A converter 3a... Color signal 4... Display 5... Processor 6 ...Lookup table banff 77...Control unit 8...Lookup table banff 7 device 9...Counter 10...\iI control circuit S,,S,...Selector and above Applicant Seiko Electronics Kogyo Co., Ltd. Figure 1 Yarai f)'r-izuf $ Ibo Ibo Aro 1. , Riseki 3rd
figure

Claims (2)

[Claims] (1) A display device comprising an image memory, a lookup table that receives image data from the image memory, a D/A converter that inputs the output of the lookup table, and a display that displays the output of the D/A converter, A look-up table buffer device for a display, characterized in that the look-up table for converting image data from the image memory into color information is provided with a look-up table buffer for processor access and for rewriting the look-up table. (2) The display lookup table buffer device according to claim 1, further comprising a control section that controls rewriting from the lookup table buffer to the lookup table.