Z89313

The Z89313 is a member of Zilog's family of Digital Television Controllers designed to provide complete audio and video control of television receivers, video recorders, and advanced on-screen display facilities.

The Z89313 features a powerful Z89C00 RISC processor core that controls on-board peripheral functions and registers using the standard processor instruction set. In closed caption mode, text can be decoded directly from the composite video signal and displayed on the screen with assistance from the processor's digital signal processing capabilities. The character representation in this mode allows for a simple attribute control through the insertion of control characters.

The Z89313 character control mode provides access to the full set of attribute controls. The modification of attributes is allowed on a character-by-character basis. The insertion of control characters permits direction of other character attributes. Display attributes, including underlining, italics, blinking, eiht foreground/background colors, character position ofset delay, and background transparency, are made possible through a fully customized 512 character set, formatted in two 256 character banks.

Serial interfacing with the television tuner is provided through the tuner serial port. Digital channel tuning  adjustments may be accessed through the industrystandard I2C port.

Additional hardware provides the capability to display two to three times normal size characters. The smoothing logic contained in the on-screen display circuit improves the appearance of larger fonts. Special circuitry can be activated to improve the visibiity of text by adding a rightsided shadow effect to the characters.

Receiver functions such as color and volume can be directly controlled by six 8-bit pulse width modulated ports.