SDA6000 Datasheet, PDF (290/380 Pages) Infineon Technologies AG – Teletext Decoder with Embedded 16-bit Controller

SDA 6000
Display Generator
10.3
Layer Concept
M2 supports two HW-layers. Frame buffers of layer 1 and layer 2 can be placed at any
word aligned position in external memory.
Two different layer modes can be chosen:
• Overlapped layers. Layer 1 and layer 2 are processed in parallel by the screen refresh
unit.
• Embedded layers. Layer 1 and layer 2 are alternatively processed.
If the area of layer 2 exceeds the area of layer 1, these parts are not visible on the
screen.
Mixing of layer 1 and layer 2 is performed by the display generator. As a result of the
RGB output of M2, there is only one RGB stream which contains the information of layer
1 and layer 2. This RGB stream is externally mixed with a video source. For this external
mixing there are two output signals (COR and BLANK) available.
Meshed areas:
A special mesh mode is defined to mix the external video with the RGB information from
M2 in a chess-pattern-shape. From frame to frame this chess-pattern is inverted.
Inverted means, that pixels which have been displayed as video in the previous frame,
are displayed as RGB in the following frame.
Blank = 1; External Video
Blank = 0; RGB of M2
t+2
t+1
t
UEA11171
Figure 10-2 Behavior of Blank Pin for Consecutive Frames in ‘Meshed’ Regions
Users Manual
10 - 5
2000-06-15