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Compressing the Mini LCD Frame Data to Save Memory Space

IP.com Disclosure Number: IPCOM000022667D
Publication Date: 2004-Mar-25
Document File: 2 page(s) / 13K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that compresses data on the mini LCD frame. Benefits include saving power and memory space in lower power modes.

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Compressing the Mini LCD Frame Data to Save Memory Space

Disclosed is a method that compresses data on the mini LCD frame. Benefits include saving power and memory space in lower power modes.

Background

The main, fully functional LCD uses a large amount of power; therefore, the mini LCD is used in low power modes instead of the main LCD. The mini LCD has a limited set of functions. However, to have all data stored in internal memory, a large amount of space is used to get all the data from the memory to the mini LCD, thereby consuming more power.

General Description

The disclosed method capitalizes on the fact that the mini LCD uses only a part of the screen when displaying information in lower power modes; the remaining portion of the screen repeats with the same color. The disclosed method compresses the data stored in memory by storing the displayed colors and the count values of the colors, which are repeated in each line.

The LCD controller supports the 16 bit RGB 1:5:5:5 format. The MSB bit of the pixel value is called the Count Value Enable. If the Count Value Enable bit of the pixel is ‘0’, the lower 15 bits represents the RGB 5:5:5 color value, as shown in Table 1. If the Count Value Enable is ‘1’, then the lower 12 bits represents the color value as shown in Table 2.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

0 Red[4:0] Green[4:0] Blue[4:0]

Table 1

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

EOL/EOF

Count Value

Table 2

If the MSB bit is equal to ‘1’, the lower 1...