PCA84C846 Просмотр технического описания (PDF) - Philips Electronics

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PCA84C846

Microcontrollers for TV tuning control and OSD applications

Philips Electronics 

Philips Semiconductors

Microcontrollers for TV tuning

control and OSD applications

Preliminary specification

PCA84C646; PCA84C846

10 DISPLAY RAM ORGANIZATION

The display RAM is organized as 64 × 10 bits.

The general format of each RAM location is as follows:

• Bits <9-4> hold data, comprising:

– Customer designed Character Font Codes (62)

– Carriage Return Code (1)

– Space Code (1).

• Bits <3-0> contain the attributes of the Character Font:

– Foreground colour and Blinking

– Character size and Line space

– Background colour and End-of-Display .

10.1 Description of display RAM codes

There are three data formats for the display RAM code

1. Character Font Code

2. Carriage Return Code

3. Space Code.

The three data formats and their descriptions are shown in

Tables 9 to 17. Figure 14 illustrates an example of the

timing of FB, R, G, and B pulses when displaying a line of

dots stream in a character.

FB = VOB; R = VOW0, G = VOW1; B = VOW2.

Figure 15 shows an example of the screen which includes

some Cariage Return and Space codes.

Table 9 Format of Character Font Code

9

8

7

6

5

4

3

2

1

0

C5

C4

C3

C2

C1

C0

T3

T2

T1

T0

Character Font Code (00H - 3DH)

Foreground colour

Blink

Table 10 Description of Character Font Code bits

SYMBOL

DESCRIPTION

C5 to C0 If bits <9-4> are in the range (00H to 3DH), then this is a Character Font Code and 1 from 62 customer

designed character fonts can be selected.

T3 to T1 Bits <3-1> determine the (Foreground) colour (1 out of 8) of this character; see Table 11.

T0

Blinking of this character is controlled by bit <0>. See Section 12.3 for duty cycle and frequency control.

When T0 = 0; blinking is OFF.

When T0 = 1; blinking is ON. Blinking rate: 1⁄16, 1⁄32, 1⁄64 or 1⁄128 × fVSYNC.

Table 11 Selection of Background and Foreground colour

T3

(RED)

0

0

0

0

1

1

1

1

T2

(GREEN)

0

0

1

1

0

0

1

1

T1

(BLUE)

0

1

0

1

0

1

0

1

COLOUR

black

blue

green

cyan

red

magenta

yellow

white

1995 Jun 15

19

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