KR20000004319A - Method of reading and writing a sequential image data at a dynamic ram at a pdp television - Google Patents

Abstract

PURPOSE: A method of reading and writing a sequential image data at a dynamic RAM at a PDP television is provided to enable the circuit to be stable. CONSTITUTION: An NTSC video signal inputted to the PDP television is rearranged by 8 bits through PISO. The rearranged image data is stored at a frame memory by using a synchronized type of dynamic RAM. One frame of image data stored at the frame memory is read according to each of sub-frames.

Description

Method of writing and reading non-interlaced video data to and from a dynamic random access memory in a plasma display panel television

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display television (PDP-TV), and to a method of recording and reading in dynamic RAM after rearranging image data sampled with 8 bits to be suitable for a PDP system.

As an image display method of a television, a cathode ray tube (CRT) currently used employs a method in which an electron gun sequentially scans pixel by pixel, and a gray scale is formed as a simple driving circuit driven by an analog system. Such CRTs are very fast with several tens of nanoseconds (ns), but it is very difficult to implement the driving of millions of pixels by one pixel when the number of pixels increases to several million, such as a high-definition television.

Meanwhile, a plasma display panel (PDP), which is recently attracting attention as a next-generation flat panel display, is an apparatus that displays an image by using light generated from plasma formed by gas discharge. It is possible to produce TV and is thinner and lighter than conventional TV, so it is the closest device to wall-mounted display. In other words, plasma refers to a state in which a substance in a gaseous state is ionized by receiving energy from an external force such as a voltage, and a plasma display uses a glow discharge region to display text, graphics, or images in a gas discharge phenomenon. Say.

The PDP has a basic property which is very suitable for large size, firstly, the PDP has a structure in which two sheets of glass are bonded at intervals of several hundred μm or less to fill gas. Therefore, the thickness is as thin as about one tenth of the cathode ray tube (CRT), and the weight can be reduced to about one sixth of the CRT.

Second, PDP drives the panel by using the Marx Driving method using the excellent nonlinearity characteristics of gas discharge. Here, nonlinearity is because the gas discharge phenomenon is caused by ionization of gas. Discharge occurs only when a voltage equal to or higher than the discharge voltage at which such an ionization reaction can occur sufficiently is a characteristic of gas discharge in which discharge does not occur at a voltage below that. Therefore, a large area panel drive is very easy because a plurality of pixels can be selectively driven without an auxiliary device by simply selecting a matrix type electrode array and selecting a gas suitable for discharge.

Third, it has a memory function, which can be referred to as a discharge memory function, whereby the discharged and non-discharged cells operate at different discharge voltages. Therefore, when the cell to be displayed is selected by the pre-discharge, the post discharge is determined by the pre-discharge. In particular, in AC PDP, the generated charge is accumulated and stored on the surface of the dielectric, so that discharge memory of a very long time is possible, and thus driving of a video is very easy.

Fourth, the wide viewing angle is wide. PDP is a self-luminous display element, and since the reflection to the partition further widens the viewing angle, a panel having a wide viewing angle of 160 degrees or more can be manufactured. Fifth, since the plasma formed by the gas discharge affects the display characteristics of the panel, even if the outside temperature changes from minus 100 ° C to the image 100 ° C, the operating characteristics of the panel do not change, and the distortion characteristics due to the magnetic field do not exist in the PDP. Does not appear

The PDP having the above characteristics is an active light emitting device in which ultraviolet rays generated from gas discharge excite a fluorescent film to implement an image. That is, since the PDP uses ultraviolet light emission by gas discharge as a light source corresponding to each pixel, the driving circuit simply functions to form or erase gas discharge for each pixel in order to implement a display image. The driving circuit includes an image signal and a signal control unit for each pixel constituting an image, and a high speed high voltage switching control unit capable of forming or erasing ultraviolet rays generated from each pixel. The driving sequence of the driving circuit of the PDP can be classified into three types: selection operation, holding operation, and erasing operation. Hereinafter, the three operations will be briefly described as follows.

The selection operation described above is a driving operation necessary for initial discharge formation. In the case of the Pen + mixture of He + Xe and Ne + Xe commonly used in the PDP, a potential of 240 V to 280 V is applied. In the case of AC PDP, a third electrode is introduced to reduce the high current caused by the sustain electrode in the surface discharge form and the parasitic capacitor caused by the dielectric, and adopt a driving method that separates the selection operation from the sustain operation.

The holding operation is a driving operation in which the discharge is held by a holding pulse of a voltage lower than the selection pulse using the memory function characteristic of the gas discharge. In the case of AC PDP, the memory function effect by wall charge is used, and in the case of DC PDP, the self-priming particle supply effect is used. As described above, in the case of the memory driving method which can separate the selection operation and the holding operation by using the memory function, the PDP operates without degrading the luminance even for a large display element in the case of high gradation display for realizing a high quality display element. It provides a driving method that can be done. In the case of AC PDP, in the period of neutralizing the wall charge, the discharge is formed at a low voltage so that the wall charge is not sufficiently formed, or the wall charge is prevented from reaching the steady state due to the erase pulse having a short pulse width. Remove

AC PDP has a unique memory function, because charged particles such as electrons and ions formed in gas discharge form wall charges in the dielectric covering the electrode. That is, there is no wall charge in the dielectric when there is no discharge, and wall charges are accumulated on the dielectric when a discharge is formed. When the wall charges are present, the potentials applied to the external electrodes and the potentials due to the wall charges are added together, so that a discharge is formed at a low voltage. Thus, it is possible to separate the operation of causing discharge at low potential with the help of addressing and discharging without the help of wall charge.

In order to display the image on the PDP by the above-described driving method, the digitized image data is stored in the memory unit after the data is rearranged in a form suitable for PDP gray level processing. The way video signals are stored in memory depends on the type of memory. The types of memory include dynamic RAM (DRAM), static RAM (SRAM) and synchronous dynamic DRAM (Synchronous DRAM). There is a need for a method of recording and reading video signals to RAM.

Accordingly, the present invention has been made in order to meet the above necessity, and when a video signal is stored using dynamic RAM as a frame memory in a PDTV, the NTSC video signal received in an interlaced manner is converted into a sequential method. The purpose is to provide a method of recording and reading back to dynamic RAM.

In the PDTV television of the present invention for achieving the above object, a method of recording the sequential video data into the dynamic RAM includes sampling the sequential scanning video signal, classifying the weight by weight through the PISO unit, and then using the dynamic RAM. A method of writing to a frame memory, the dynamic RAM comprising: an MSB weight storage row zone, an M-1 weight storage row zone, an M-2 weight storage row zone,. A first step of dividing the M-6 weight storage row region and the LSB weight storage row region; The first to eighth sampled image data of the first line includes {first MSB row, first M-1 row,... , 1M-6 rows, 1 LSB rows}, and the 9-16th sampled image data of the first line is stored as {second MSB row, 2M-1 rows,... , Lines 2M-6 and 2LSB, respectively, by weight, and the above-described process is repeated to store the image data of the first line in the {MSB row area, M-1 row area,... A second step of storing the respective weights in the M-6 region and the LSB region; And repeating the second process with respect to the second to the 480th lines, so that the image data of the second line includes the {MSB area, M-1 row area,... , Section M-6, section LSB}, by weight, , The image data of line 480 is defined as the {MSB line, M-1 line,. , M-6, and LSB, each of which comprises a third process of storing each weight.

Further, in the PDTV television according to the present invention, a method of reading sequential video data from the dynamic RAM includes subframes of video data of one frame from the dynamic RAM in which the sampled video data is recorded for each vertical line and for each weight. In the reading method, all data stored in the MSB row region of the first column is read to read all the MSB weight data of the first vertical line, and all data stored in the MSB row region of the second column is read to the second vertical line. Read all MSB weight data,… Reading all the MSB subframes by reading all the data stored in the MSB row region of column 480 to read all the MSB weight data of the 480 vertical lines; Jump to row M-1 of the first row and read all M-1 weight data of the first vertical line from row M-1 of the first row; A second step of reading all M-1 subframes by reading all M-1 weight data of the 480 vertical lines from the M-1 row region of the 480th column; And subtracting the M-2 subframe from the row M-2 of the first row and the row M-2 of the 480th column, in the same manner as the first and second processes, Read the M-3 subframe from the M-3 row region of column 480,... And a third process of reading the LSB subframe from the LSB row region of the first column to the LSB row region of the 480th column.

1 is a block diagram showing the configuration of a general all AC PDP-TV system;

FIG. 2 is a block diagram illustrating a configuration of a memory unit in FIG. 1;

3 is a state diagram showing a data format of the sampled video data sorted by an 8-bit PISO stage;

4 is a memory map of a frame memory using dynamic RAM for storing 8-bit data according to the present invention.

Explanation of symbols on the main parts of the drawings

112: antenna 114: AV part

116: ADC unit 117: interlaced / sequential conversion unit

118: memory unit 120: data interface unit

122: timing controller 124: AC-DC converter

126: high voltage drive circuit unit 128: scan / maintenance drive IC

130, 132: address driver IC 134: PDP panel

210: data rearrangement unit 211: first PISO unit

212: PISO part 213: D flip flop and multiplexer

214: first tri-state buffer 215: second tri-state buffer

220: address generator 221: recording address generator

222: read address generator 223: address selector

230: first frame memory 240: second frame memory

250: data selector

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows the entire AC type PDP-TV system according to the present invention, the AV unit 114 receives the NTSC composite video signal through the antenna 112, horizontal and vertical synchronization with analog R, G, B The synchronous signal is separated, an average picture level (APL) corresponding to the average value of the brightness signal (Y) is obtained, and provided to the ADC unit 116. The NTSC composite video signal is composed of two fields of Odd / Even in an interlaced scanning method.

The ADC unit 116 receives analog R, G, and B signals as inputs and converts them into digital data, and the interlaced / sequential converter 117 converts the interlaced video signals into sequential scan video signals and stores the memory. Output to the unit 118, wherein the digital data is the image data of the converted form to improve the brightness of the PDP-TV system. The ADC unit 116 is largely divided into an amplifier, a clock generator, a sampling area setting unit, and a data mapping unit.

The memory unit 118 reconstructs image data of one field into a plurality of subfields for grayscale processing of the PDP, and then rearranges the most significant bit (MSB) to the least significant bit (LSB). As shown in FIG. 2, the memory unit 118 includes a data rearranger 210, an address generator 220, a control clock generator (not shown), and first and second frame memories 230 and 240. And a data selector 250.

Referring to FIG. 2, the data rearrangement unit 210 includes two parallel input serial output (PISO) units 211 and 212, a D flip flop and a multiplexer 213, and two tri-state buffers 214 and 215. The image data provided in parallel (MSB to LSB) in the unit 116 is rearranged so as to store bits having the same weight (weight) in one address of the two frame memories 230 and 240.

That is, the first PISO unit 211 and the second PISO unit 212 alternately repeat the load operation and the shift operation to classify the sampled image data by weight, and the eight image data in which the first PISO unit 211 is sampled. During loading, the second PISO unit 212 outputs eight image data previously loaded while sequentially shifting from the most significant bit MSB to the least significant bit LSB. In addition, while the first PISO unit 211 outputs the image data loaded by the weight by shifting, the second PISO unit 212 loads the eight sampled image data again.

The D flip flop and the multiplexer 213 selects the same weighted data output in the shift mode among the first PISO unit 211 and the second PISO unit 212 and supplies them to two tri-state buffers 214 and 215. The two tri-state buffers 214 and 215 connect rearranged image data provided from the D flip flop and the multiplexer 213 to the frame memories 230 and 240 operating in the recording mode.

In general, in the case of a PDP TV having an aspect ratio of 16 to 9, the capacity of the frame memories 230 and 240 capable of storing image data of one frame may be obtained as in Equation 1.

853 × 3 (R, G, B) × 480 × 8bit ≅ 10Mbit

That is, two frame memories 230 and 240 of 10 Mbit capacity are used to alternately perform writing and reading operations in units of frames.

The address generator 220 of FIG. 2 is divided into a write address generator 221 and a read address generator 222. The address generator 220 generates an address of data stored in one frame memory 230 and 240 and provides the address to the frame memory 230 and 240. do. In order to process the PDP gray level, the subfields are divided by weight of all image data constituting one frame, and when reading, the image data corresponding to each frame must be read in sequence and provided as a data interface. The read address generators 222 are very different from each other. The address selector 223 provides a corresponding address to the first and second frame memories 230 and 240 according to each operation mode of the first frame memory 230 and the second frame memory 240, that is, a write mode or a read mode. Do it.

The data selector 250 selects image data output from the frame memory operating in the read mode among the first and second frame memories 230 and 240 and provides the image data to the data interface unit 120.

The data interface unit 120 of FIG. 1 temporarily stores R, G, and B data supplied from the memory unit 118 and provides the data in the form of data required by the address driver ICs 130 and 132. That is, the R, G, and B data output from the memory unit 118 should be rearranged and supplied to the address driver ICs 130 and 132 according to the RGB pixel arrangement of the panel 134. A space for temporarily storing data of line amount (640 lines x 3 (R, G, B) x 2 = 3840 bits) is required. While inputting one line of data, the operation of outputting the data of another line is alternated. To perform.

The high voltage driving circuit unit 126 combines the DC high voltage supplied from the AC-DC converter 124 according to the control pulses of various logic levels output from the timing controller unit 122 to the scan / maintenance driving IC 128. The control pulse required may be generated to drive the PDP panel 134. In addition, the data stream provided from the data interface unit 120 to the address driver ICs 130 and 132 is also raised to an appropriate high voltage level to enable selective recording on the panel.

FIG. 3 shows a format of data sorted into 8-bit PISO units. That is, the data of D0 is an MSB of 8-bit image data sampled 1 to 8 times, D1 is M-1 of 8-bit image data sampled 1 to 8 times, and D2 is M of 8-bit image data sampled 1 to 8 times. -2, … , D7 denotes an LSB of 8-bit image data sampled from 1 to 8 times, and D8 denotes an MSB of 8-bit image data sampled from 9 to 16 times. Denotes the LSB of 8-bit image data sampled at the 9th to 16th times.

On the other hand, since the PDP system displays one frame of image data by weight, the following amount of frame memory is required.

That is, in 640x480 mode, 640x480x8bit = 2,457,600bits of memory per channel (e.g. R channel) is required, and 640 ÷ 8 = 80 times of addressing per line for 8bit processing. Do. In the wide mode 853x480 mode, 853x480x8bit = 3,275,520bits of memory per channel is required, and 853 ÷ 8 ≒ 107 addressing per line is needed for 8bit processing.

FIG. 4 shows a memory map of a frame memory using dynamic RAM for storing 8-bit image data sorted by weight from the first and second PISO units. The dynamic RAM includes an MSB row region for storing MSB weight data. , M-1 row area for storing M-1 weight data, M-2 row area for storing M-2 weight data,... It is divided into an M-6 row area for storing M-6 weight data, and an LSB row area for storing LSB weight data.

A general NTSC video signal is input by interlaced scanning. Since the interlaced / sequential converting unit converts the interlaced scanning video signal into a sequential scanning video signal, the sequential video signals are classified and input into the memory unit. .

As described above, a method of recording image data in the dynamic RAM for each weight will be described with reference to the memory map of FIG. 4.

8-bit image data is recorded in one column address. In the 640x480 mode, since 80 times (640 ÷ 8) of addressing is required per line, 80 rows are required for each row area. That is, the MSB line, M-1 line,... Each of the three sections, M-6 and LSB, consists of at least 80 rows. In addition, in the 853 × 480 mode, 107 (853 ÷ 8) addressings are required per line, in which case, the MSB line area, M-1 line area,... Each of the three sections, line M-6 and line LSB, consists of at least 107 lines. In the sequential scanning method which is common to the above-described 640x480 mode and 853x480 mode, the dynamic RAM is divided into 480 columns because there are 480 vertical lines.

First, the dynamic RAM includes the MSB weight storage row zone, the M-1 weight storage row zone, the M-2 weight storage row zone,. It is divided into M-6 weight storage row area and LSB weight storage row area.

When the image data of the sequential method is classified and inputted by weight, the image data sampled in the first to eighth times of the first line is displayed in the first column {first MSB row, first M-1 row,... , 1M-6 rows, 1 LSB rows}, and the 9-16th sampled image data of the first line is stored as {second MSB row, 2M-1 rows,... , Lines 2M-6 and 2LSB} for each weight. The above process is repeated 80 times in the 640 × 480 mode and 107 times in the 853 × 480 mode. The repetition of the image data of the first line results in the {MSB row region, Area M-1,… , Area M-6 and area LSB} are stored for each weight.

In addition, the above process is repeated for the second to the 480th lines, and the image data of the second line is repeated in the {MSB area, M-1 row area,. , Section M-6, section LSB}, by weight, , The image data of line 480 is defined as the {MSB line, M-1 line,. , Area M-6, area LSB} by weight.

Therefore, image data for one frame is classified and stored for each vertical line and for each weight.

A method for reading image data recorded in the dynamic RAM for each subframe by the above-described method will be described with reference to the memory map of FIG. 4.

First, when a data read signal is input, all data stored in the MSB row region of the first column is read, all MSB weight data of the first vertical line is read, and all data stored in the MSB row region of the second column is read. Read all MSB weight data of vertical line,… Read all the data stored in the MSB row area of column 480 to read all the MSB weight data of the 480 vertical lines. This allows the MSB subframe to be read.

Next, jump to the M-1 row area of the first row, and read all the M-1 weight data of the first vertical line from the M-1 row area of the first row, and. In step 480, the M-1 weight data of the 480 vertical lines is read from the M-1 row area of the 480th column, thereby reading the M-1 subframe.

In addition, the above-described reading method is applied to the M-2 subframe to the LSB subframe, and the M-2 subframe is read from the M-2 row region of the first column and the M-2 row region of the 480th column, Reads the M-3 subframe from the M-3 region of the column to the M-3 region of the column 480; The LSB subframe is read from the LSB row region of the first column to the LSB row region of the 480th column.

As described above, the present invention can provide a method of recording interlaced image data into a frame memory using a dynamic RAM having a relatively low cost, and providing a method of reading image data from the frame memory, thereby improving circuit reliability. In addition, the cost can be reduced.

Claims (2)

In the method of sampling the video signal of the sequential scanning method and classifying by weight through the PISO unit and recording in the frame memory using the dynamic RAM, Dynamic RAMs include MSB weight storage row zones, M-1 weight storage row zones, M-2 weight storage row zones,. A first step of dividing the M-6 weight storage row region and the LSB weight storage row region; The first to eighth sampled image data of the first line includes {first MSB row, first M-1 row,... , 1M-6 rows, 1 LSB rows}, and the 9-16th sampled image data of the first line is stored as {second MSB row, 2M-1 rows,... , Lines 2M-6 and 2LSB, respectively, by weight, and the above-described process is repeated to store the image data of the first line in the {MSB row area, M-1 row area,... A second step of storing the respective weights in the M-6 region and the LSB region; And By repeating the second process with respect to the second to the 480th lines, the image data of the second line is displayed in the {MSB row area, M-1 row area,... , Section M-6, section LSB}, by weight, , The image data of line 480 is defined as the {MSB line, M-1 line,. And a third process of storing the respective weights in the M-6 region and the LSB region, respectively, in the dynamic RAM according to the present invention. In the method of reading the image data of one frame for each subframe from the dynamic RAM in which the sampled image data is recorded for each vertical line and for each weight, Read all the MSB weight data of the first vertical line by reading all data stored in the MSB row area of the first column, and read all the MSB weight data of the second vertical line by reading all the data stored in the MSB row area of the second column. … Reading all the MSB subframes by reading all the data stored in the MSB row region of column 480 to read all the MSB weight data of the 480 vertical lines; Jump to row M-1 of the first row and read all M-1 weight data of the first vertical line from row M-1 of the first row; A second step of reading all M-1 subframes by reading all M-1 weight data of the 480 vertical lines from the M-1 row region of the 480th column; And In the same manner as in the first and second processes, the M-2 subframe is read out from the M-2 row area of the first column, and the M-2 row area of the 480th column, and the M-3 area to the 480th row of the first row. Read the M-3 subframe from the M-3 row region of the column,. And a third process of reading the LSB subframe from the LSB row section of the first column to the LSB row section of the 480th column.