ADV473

–8–

REV. A

Command Register (CR)

The ADV473 has an internal command register (CR). This reg-

ister is 8 bits wide, CR0–CR7 and is directly mapped to the

MPU data bus on the part, D0–D7. The command register can

be written to or read from. It is not initialized, therefore it must

be set. Figure 4 shows what each bit of the CR register controls

and shows the values it must be programmed to for various

modes of operation.

Color Modes

The ADV473 supports four color modes, 24-bit true-color,

15-bit true-color, 8-bit true-color and 8-bit pseudo-color. The

mode of operation is determined by the S0 and S1 inputs, in

conjunction with CR7 and CR6 of the command register. S0

and S1 are pipelined to maintain synchronization with the video

data. Table III illustrates the modes of operation.

Table III. Color Operation Modes

OL3–OL0

S1, S0

CR7, CR6

Mode

R7–R0

G7–G0

B7–B0

1111

XX

XX

Overlay Color 15

XXH

XXH

XXH

.

.

.

.

...

.

.

.

.

...

0001

XX

XX

Overlay Color 1

XXH

XXH

XXH

0000

00

00

24-Bit True-Color

R7–R0

G7–G0

B7–B0

0000

00

01

24-Bit True-Color

R7–R0

G7–G0

B7–B0

0000

00

10

24-Bit True-Color

R7–R0

G7–G0

B7–B0

0000

00

11

Reserved

Reserved

Reserved

Reserved

0000

01

00

24-Bit True-Color Bypass

R7–R0

G7–G0

B7–B0

0000

01

01

24-Bit True-Color Bypass

R7–R0

G7–G0

B7–B0

0000

01

10

24-Bit True-Color Bypass

R7–R0

G7–G0

B7–B0

0000

01

11

Reserved

Reserved

Reserved

Reserved

0000

10

00

8-Bit Pseudo-Color (Red)

P7–P0

Ignored

Ignored

0000

10

01

8-Bit Pseudo-Color (Green)

Ignored

P7–P0

Ignored

0000

10

10

8-Bit Pseudo-Color (Blue)

Ignored

Ignored

P7–P0

0000

10

11

15-Bit True-Color

Orrrrrgg

gggbbbbb

Ignored

0000

11

00

8-Bit True-Color Bypass (Red)

rrrgggbb

Ignored

Ignored

0000

11

01

8-Bit True-Color Bypass (Green)

Ignored

rrrgggbb

Ignored

0000

11

10

8-Bit True-Color Bypass (Blue)

Ignored

Ignored

rrrgggbb

0000

11

11

15-Bit True-Color Bypass

Orrrrrgg

gggbbbbb

Ignored

X = Don’t Care

CONTROL OUTPUTS

THESE BITS ARE OUTPUT

ONTO THE CR3-CR0 PINS

CR5

0

1

0 IRE

7.5 IRE

PEDESTAL ENABLE

CONTROL (SETUP)

CR4

0

1

6-BIT

8-BIT

8-BIT/6-BIT

COLOR SELECT

COLOR MODE

SELECT

(SEE TABLE III)

CR5

CR4

CR3

CR2

CR1

CR7

CR6

CR0

Figure 4. Command Register (CR)