CRT Video Attributes Controller
o On chip video shift register (28.5 MHz max.)
o On chip attributes logic
o Four modes of operation
Character mode without underline
Character mode with underline
o On Chip logic for double height/double
o Accepts scan line information in parallel
or serial format
o Four cursor modes dynamically selectable via 2
Blinking reverse video
o Programmable character blink rate
o Programmable cursor blink rate
PACKAGE 28-pin D.I.P.
o On chip data and attribute latches
o + 5 volt operation
o TTL compatible
o MOS n-Channel silicon gate COPLAMOS® processM
o Compatible with CRT 5037 VTAC®; CRT 9007 VPAC
The SMC CRT 9021 Video Attributes Controller line, reVerse video character block, and blinking
(VAC) is an n-channel COPLAMOS MOS/LSI device reverse video character block. When used in the serial
containing Graphics logic, attributes logic, data and scan line input mode, the cursor mode may be selected
attributes latches, cursor control, and a high speed via two input pins. When used in the parallel scan line
video shift register. The CRT 9021 , a character gen- input mode, the cursor mode is a mask program option
erator ROM and a CRT controller such as the CRT and is fixed at the time of manufacture.
9007 provide all of the major circuitry for the display
Two graphics modes are provided. In the wide
portion of a CRT video terminal.
graphics mode, the CRT 9021 produces a graphic
The CRT 9021 serial video output may be con- entity the size of the character block. The graphic entity
nected directly to a CRT monitor's video input. The contains eight parts, each of which is associated with
maximum video shift register frequency of 28.5 MHz one bit of the input byte, thereby providing 256 unique
allows for CRT displays of up to 132 characters per graphic symbols. The thin graphics mode enables the
user to create thin line drawings and forms.
The CRT 9021 attributes include: reverse video,
In both graphics modes, continuous horizontal and
underline, character blank, character blink, and full/ vertical lines may be drawn. Additional flexibility is
half intensity selection. In addition, when used in con- provided by allowing the mask programming of the
junction with theCRT9007VPAC;M the CRT 9021 will placement and dimensions of the blocks or lines within
provide double height or double width characters.
a character block. In the thin graphics mode, mask
Four programmable cursor modes are provided on programming allows serrated horizontal or vertical
the CRT 9021. They are: underline, blinking under- lines.