CN101520990B

CN101520990B - System for low power consumption of liquid crystal display controller

Info

Publication number: CN101520990B
Application number: CN2008100202332A
Authority: CN
Inventors: 刘翔; 何咏; 刘文江
Original assignee: WUXI ALPSCALE INTEGRATED CIRCUITS CO Ltd
Current assignee: Dongguan Runfeng Electronic Science and Technology Co., Ltd.
Priority date: 2008-02-28
Filing date: 2008-02-28
Publication date: 2012-07-18
Anticipated expiration: 2028-02-28
Also published as: CN101520990A

Abstract

The invention discloses a system design for the low power consumption of a liquid crystal display controller; the design integrates an on-chip RAM embedding-type chip with a certain size to the systemand a software design which coordinates with the hardware is provided. On a specific application condition that the software code is less and can be directly stored in an on-chip storage unit, a plug -in memory of the embedding-type chip is stopped using, and only the on-chip RAM is used for storing and fetching image data and software codes so as to achieve the aim of reducing power consumption.

Description

The system of low power consumption of liquid crystal display controller

Technical field

The present invention relates to a kind of system design of low-power consumption of LCD controller, can be widely used in portable set and handheld device, be used to reduce system power dissipation.

Background technology

In the present digital mobile terminal equipment; Have a slice embedded type CPU chip at least, but this not enough, owing to receive the restriction of chip manufacturing cost and chip manufacturing process; Can not be in integrated very big storage unit inside the embedded chip; So generally need plug-in a slice storage unit such as SDRAM, and also want plug-in a slice flash chip FLASH sometimes, be used to deposit the code of running software.After the start operation, the SDRAM storer reads out software code from flash chip FLASH, and in CPU, moves.

For the software application on the operating system aspect; Need bigger storage unit SDRAM of configuration, but for some certain applications, such as common learning machine; The code of software is few on the one hand; Can directly embed the storage unit in the chip, in the special time period of using, each pixel of video image can be represented with less bit position on the other hand; Can be stored in the storage unit in the chip after the Image Data Compression with a frame like this, and can not use plug-in storage unit to reduce power consumption in this case.

Summary of the invention

In order to cooperate software code less, can directly be stored in the situation of sheet stored unit, the invention provides a kind of technical scheme of gathering monitoring and statistical picture data stream function.When starting this function; Hardware can at first be monitored the rgb image data that arrives LCD controller; If is that kind according to certain the specific mode and the image color of monitoring out is no more than 16 kinds at tens frames and even tens frames with interior image; We just suppose that the image color in a period of time of back also is this image that is no more than 16 kinds of colors, and the color that this time, software came out monitoring is formed a color index table and is stored in the color index register of hardware system.Later image color is at first retrieved in the color index table, on LCD, shown after finding corresponding color index.Since this concordance list be controlled in 16 numbers according to this in (comprising 16); Thereby only need just can represent the value of a pixel with 4 bit positions; Storage space has just been practiced thrift in expression with respect to the pixel of original 16bit or 24bit widely; So just can stop using sheet external memory cell S DRAM, thereby reach the purpose that reduces power consumption.

The present invention mainly is made up of RGB data stream monitoring and statistics module.RGB data stream monitoring and statistics module is work like this: when software code can be placed among the RAM in the sheet; At demonstration RGB444, in the time of the data image of RGB565 or RGB888 form, start the monitoring function of pixel; In RGB data arrives LCD Controller port, the data stream of RGB is monitored; Because data stream is through very fast, thus we adopt and whenever monitor a pixel at a distance from 16 pixels, if when in this pixel and the collection of pixels of monitoring out one is identical; Continue to detect next; If all inequality in pixel and the detected collection of pixels, the and at this moment pixel in the collection of pixels has been 16 just produces and interrupts and finish monitoring.Only the pixel in collection of pixels is less than 16 kinds, and after observation process was all monitored the view data of front tens frames or tens frames, monitoring stopped.Related three registers of monitoring modular, one is the Monitoring and Controlling register, and one is the switching register that reads image data switches to reads image data in the sheet from sheet outside, and one is the color index register in addition.These three registers have been accomplished the switching that outside sheet reads image data switches to reads image data in the sheet under the coordination of software.The RGB display control module produces frame synchronization and interrupts; The effect of this interruption is the switching of accomplishing display mode; Comprise two kinds of switch modes; A kind of is that reads image data switches to reads image data in the sheet outside sheet, and another kind is that reads image data switches to reads image data outside the sheet in sheet.When producing the monitoring interruption, software judges from the color index register at first whether the pixel kind of monitoring has out surpassed 16 kinds, if surpassed, that does not just do any switching.Only the color in color register is within 16 kinds; Software systems are prepared the environment of switching; The ram space of at first dividing in the sheet is deposited view data and color index table, again in the color index register this is no more than 16 kinds of colors and is stored in the color index table among the RAM.If adopt the DMA transmission, also need be ready to data packets for transmission, this data transmission has comprised two parts, and one is the data transmission of color table, and one is the packet of the RGB index data in the transmission sheet.When these preliminary works are done, again the switching register in the LCD controller is sent pulse signal.

After producing the signal of two interruptions, controller just outside sheet reads image data switch to reads image data in the sheet.And stop power supply, reach the purpose that reduces system power dissipation to external memory unit SDRAM.

Description of drawings

Fig. 1 is the structured flowchart of this LCD controller.

To be that software and hardware is collaborative read the RGB data and switch to the process flow diagram that reads the RGB data in the sheet Fig. 2 outside sheet.

Embodiment

Suitable software code of the present invention is less, can directly be stored in the situation of sheet stored unit, and adopt and do not use the SDRAM storer, thus the power consumption of reduction liquid crystal display systems.The present invention provides the function of monitoring and statistics image stream, to demonstration RGB444, in the time of the data image of RGB565 or RGB888 form, launches monitoring of the present invention and statistical picture data module.Because data stream is through very fast; So we adopt whenever at a distance from pixel of 16 pixel monitorings; When if in this pixel and the collection of pixels of monitoring out one is identical, continue to detect next, if all inequality in pixel and the detected collection of pixels; And at this moment the pixel in the collection of pixels has been 16, just produces to interrupt and finish monitoring.Only the pixel in collection of pixels is less than 16 kinds, and after observation process was all monitored the view data of front tens frames or tens frames, monitoring stopped.At first judge the type that monitoring is interrupted, only in pixel during less than 16 kinds, software systems are prepared the environment that switches.The ram space of at first dividing in the sheet is deposited view data and color index table, again in the color index register this is no more than 16 kinds of colors and is stored in the color index table among the RAM.If adopt the DMA transmission, also need be ready to data packets for transmission, this data transmission has comprised two parts, and one is the data transmission of color table, and one is the packet of the RGB index data in the transmission sheet.When these preliminary works are done, again the switching register in the LCD controller is sent pulse signal.Receive the pulse signal of switching register when system of the present invention after, just the outer reads image data of sheet is switched to reads image data in the sheet, and stop power supply, reach the purpose that reduces system power dissipation to external memory unit SDRAM.

Claims

1. a low power consumption of liquid crystal display controller system is characterized in that: comprise a ram in slice, a sheet external memory chip, monitoring of a RGB data stream and statistical module and a RGB display control module; Said ram in slice is integrated in this system; The image color that goes out with interior image monitoring at tens frames and even tens frames is no more than 16 kinds; Software code is less can directly to be stored under the situation of said ram in slice; Said external memory chip stopped using, only use said ram in slice to come accessing image data and software code;

Said RGB data stream monitoring and statistical module are when software code can be placed among the RAM in above-mentioned; At demonstration RGB444, in the time of the data image of RGB565 or RGB888 form, start monitoring of RGB data stream and statistical module; Adopt whenever at a distance from pixel of 16 pixel monitorings; When if in this pixel and the collection of pixels of monitoring out one is identical, continue to detect next, if all inequality in pixel and the collection of pixels of monitoring out; And the pixel in the collection of pixels has been 16 at this moment, and said RGB data stream monitoring and statistical module just produce and interrupt and the end monitoring; Only the pixel in collection of pixels is less than 16 kinds, and after observation process was all monitored the view data of front tens frames or tens frames, monitoring stopped; When producing the monitoring interruption, judge whether the pixel kind of monitoring has out surpassed 16 kinds, if surpassed, that does not just do any switching; Only in pixel during less than 16 kinds; The RGB display control module produces frame synchronization and interrupts; The effect of this interruption is the switching of accomplishing display mode, switches to reads image data in the sheet from sheet external memory chip reads image data, and stops to the exterior storage chip power supply.