TPU2735 Ver la hoja de datos (PDF) - Unspecified

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componentes Descripción

Fabricante

TPU2735

Teletext Processor

Unspecified 

TPU 2735

3.3. Pin Descriptions (for 40-pin DIL package)

Pin 1 to 4 and 39, 40 – Video Inputs V1 to V6 (Fig. 3–4)

Inputs for the digitized composite video signal from the

VCU 213x or VAD 2150. The video signal uses a parallel

Gray code, input V6 is the most significant bit (MSB).

Pin 5 – Ground, 0 V

Pins 6 to 9 – R, G, B and Fast Blanking Outputs (Fig. 3–6

and 3–7)

The R, G and B outputs deliver the Teletext RGB signal

to the additional RGB inputs (pins 30 to 32) of the VCU

2133 or VCU 2134 in the case of Teletext operation. The

fast blanking output serves for switching the video chan-

nel between normal TV and Teletext operation. It must

be connected to the fast blanking input (pin 33) of the

VCU.

Pin 10 – Fast Blanking Input (Fig. 3–10)

This pin is used to switch over to an external RGB

source. The external RGB signal is connected to pins 32

to 34 of the TPU 2735. A low level at pin 10 switches the

external RGB signal to the RGB outputs of the TPU

2735 and enables the Fast Blanking Output (pin 9 high).

Pin 10 floats to a high level if not connected. The RGBE

control bit sets the priority to the external RGB inputs if

both, teletext and external RGB are active. Two bits in

the IM Bus Hardware test/configuration register (see

section 6.4.) allow to select the polarity of pin 10 and

overwrite the fast blank signal.Boxes of TPU text can be

cut into an external RGB signal. The RGB and blanking

outputs are controlled according to the table below. The

settings TTM=1 and RGBE=0 are recommended for

normal Teletext. For on-screen display, TTM=1 and

RGBE=1 are recommended. For clarification, the con-

nections are shown in Fig. 3–2 and the TV display ap-

pearance in Fig. 3–3.

Video from VCU

TPU 2735

Chroma and Luma

from VPU or

CVPU

VCU

32,

33,

34

Ext.

RGB 10

Teletext

RGB Bl

6,

7,

8

Logic

30,

31,

32

9

33

RGB

to CRT

26,

27,

28

14,

RGBE Flag 15,

16

IM Bus

Fig. 3–3: Signal paths for RGB signals in TPU 2735

and VCU 2133 or VCU 2134

Insert Mode = FBL (Pin 10) active Low

On-Scr .

SCART

(ext. RGB)

Display TV

a) TTM = 1, RGBE= 0

On-

Screen

Display

(Text)

TV

b) TTM = 1, RGBE = 1

Fig. 3–4: Priorities on the screen, depending on

TTM and RGBE

TTM

RGBE

0

0

0

1

0

0

1

0

1

0

1

0

1

1

1

1

1

1

x = don’t care

* = see Fig. 3–2 and 3–3

8

Ext. Fast

Blanking

Pin 10

1

x

0

1

1

0

x

1

0

Internal TPU

Text Blank-

ing

0

0

0

0

1

x

1

0

0

Fast Blank-

ing Output

Pin 9

0

1

1

0

1

1

1

0

1

RGB Output

Pins 6 to 8

pins 32 to 34

pins 32 to 34

pins 32 to 34

Text

Text

pins 32 to 34

Text

pins 32 to 34

pins 32 to 34

Screen*

Video

SCART

SCART

Video

Text

SCART

Text

Video

Scart

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