Card/Circuit Description; Block Diagram - Zenith Data Systems Z-100 Series Installation Manual

Chapter 5
Card/Circuit Description
This chapter describes the Z-329 Card from a hardware viewpoint. The
components on the card and the operation of the circuit are described.
The Z-329 Monochrome Video Card produces 25 rows of 80 characters.
The computer system transfers alphanumeric characters to the Z-329 Card
in ASCII code. The character and an attribute byte are stored in the RAM
on the Z-329 Card. When the character is to be displayed, the CRTC
addresses the memory and a character ROM decodes the ASCII data
into pixel lighting instructions.
Block Diagram
Figure 5.1 illustrates the block diagram of the Z-329 Card. Refer to this
illustration for the following discussion.
SYSTEM BUS
TO MONITOR
Figure 5.1. Z-329 Card Block Diagram