Z89318

The Z89314/318 Z89318 are members 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 powerful Z89C00 Z89318 RISC processor core allows users to control 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 Z89318 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 include underlining, italics, blinking, eight foreground/background colors, character position offset 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. This version of the Z89300 series does not offer I2C capability.

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. Fringing circuitry can be activated to improve the visibiity of text by surrounding the character lines with a one-pixel border.

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