SAB9081H Просмотр технического описания (PDF) - Philips Electronics

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SAB9081H

Multistandard Picture-In-Picture (PIP) controller

Philips Electronics 

Philips Semiconductors

Multistandard Picture-In-Picture (PIP)

controller

Preliminary specification

SAB9081

FUNCTIONAL DESCRIPTION

Acquisition

The internal pixel rate is 28 MHz for the Y, U and V

channels. It is expected that the bandwidth of the input

signals will be limited to 4.5 MHz for the Y input and

1.125 MHz for the U and V inputs. Inset synchronisation is

achieved via the acquisition HSYNC and VSYNC pins of

the main channel. The display is driven by the main

channel clock.

The starting-point of the acquisition can be controlled with

the acquisition fine positioning added to a system

constant. With a nominal input fHSYNC and standard NTSC

signals, 1408 samples (active video) are acquired and

processed by the SAB9081. Here, the nominal input

fHSYNC results in a nominal system clock frequency of

1792 × fHSYNC (approximately 28 MHz).

PIP modes

handbook, full pagewidth

MAIN

SUB

SUB

MAIN

MAIN

REPLAY

SUB

MGM810

Fig.3 Pip modes.

I2C-bus description

The I2C-bus provides bidirectional 2-line communication

between different ICs. The SDA line is the serial data line

and the SCL the serial clock line. Both lines must be

connected to a positive supply via a pull-up resistor when

connected to the output stages of a device.

Data transfer may be initiated only when the bus is not

busy. The SAB9081 has the I2C-bus address 2CH. Valid

subaddresses are 00H to 18H; register 15H (except bits 7

and 6) and registers 16H to 18H are reserved for future

extensions.

I2C-bus control is according to the I2C-bus protocol: first, a

START sequence must be put on the I2C-bus. Then, the

I2C-bus address of the circuit must be sent, followed by a

subaddress. After this sequence, the data of the

subaddresses must be sent. An auto-increment function

gives the option of sending data of the incremented

subaddresses until a STOP sequence is sent. Table 1

gives an overview of the I2C-bus addresses. The data bits

that are not used should be set to zero.

1999 Nov 12

7

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