AL701 Ver la hoja de datos (PDF) - AverLogic Technologies Inc

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componentes Descripción

Fabricante

AL701

QUAD Video Processor

AverLogic Technologies Inc 

AL700/701/710

RAM Addre s s

Generator 1

RAM Addre s s

Generator 2

Context RAM

ADDR

9

Context

RAM

MUX

ContextRAM

DATA

16

Font RAM

Addre s s

Generator 1

Font RAM

Addre s s

Generator 2

Font RAM

ADDR

12

Font

RAM

4K x 8

Font RAM

DATA

8

Unpacker

OSDKEY

1/2

MUX

Figure 14: The Addressing of Context and Font RAMs

The font addressing code can be in 1-byte or 2-byte formats. CONTEXTSTADDR1

(#36h) and CONTEXTSTADDR2 (#46h) are the starting addresses of the Character

codes of OSD1 and OSD2 stored in Context RAM. The starting address should be an

even number in the 2-byte data mode. The Character code is used to address the font data

stored in Font RAM. The address of a data of a specific font is calculated as:

Address = Font RAM Start Address + (Character code * Font Address Unit) + (OSD line

count * FONTLINESIZE)

The data format stored in Context RAM for addressing of OSD bitmap data is illustrated

in the following diagram.

Font Index for one byte data mode

Font Index for Two byte data mode

00h Reserved<7> 1st Character code <6:0>

01h Reserved<7> 2nd Character code <6:0>

02h Reserved<7> 3rd Character code <6:0>

03h Reserved<7> 4th Character code <6:0>

04h Reserved<7> 5th Character code <6:0>

05h Reserved<7> 6th Character code <6:0>

06h Reserved<7> 7th Character code <6:0>

3FFh Reserved<7> 1024th Character code <6:0>

00h

1st Character code <7:0>

Foreground

Background Blink

01h

Color <7:6>

Color <5:4> <3>

Character code

<10:8>

02h

Character code <7:0>

Foreground

Background Blink

03h

Color <7:6>

Color <5:4> <3>

Character code

3FEh

3FFh

Foreground

Color <7:6>

512th Character code <7:0>

Background

Color <5:4>

Blink

<3>

Character code

Figure 15: OSD Data Addressing in Context RAM

7.8.2 Internal OSD Timing

The register OSDHSTART (#34h or #44h) refers to the horizontal starting position of the

OSD window relative to the leading edge of HSYNC. OSDVSTART (#35h or #45h)

refers to the vertical starting position of the OSD window relative to the leading edge of

VSYNC. The BMAPHSIZE (#38h or #48h) defines the horizontal visible portion of the

font (it can be smaller or equal to the actual horizontal font size). BMAPHTOTAL (#39h

or #49h) is BMAPHSIZE plus the horizontal size of the border or gap in between fonts.

The BMAPVSIZE (#3Ah or #4Ah) defines the vertical visible portion of the font (it can

be smaller or equal to the actual vertical font size). BMAPVTOTAL (#3Bh or #4Bh) is

©2001,2002-Copyright by AverLogic Technologies, Corp. Preliminary Version C1.1 24

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