Input/output (I/O) controller
Tabular video generator
O-DATA RECEIVERS. The O-data receivers
accept 32 bits of parallel computer data, provide the
proper level shifting, and send the computer data to
the I/O controller.
( I / O ) c o n t r o l l e r m a n a g e s t h e
communication with the system computer. The I/O
controller receives computer data through the O-data
receivers and sends data to the computer through the
There are two identical I/O
channels in the C-DITEG, although only one maybe
active at any time. Channel 0 is the default channel;
and if the active channel fails, the normally idle
channel will become active.
The I/O controller decodes incoming computer
data for C-DITEG control words or display data
words. Display data is sent to system memory.
CONTROL SYNCHRONIZER. The control
synchronizer uses four crystal oscillators to generate
the system clocks. The crystal oscillators generate 40-
MHz, 27-MHz, 24-MHz, and 16-MHz clocks. The
40-MHz clock is divided by two and four to generate
50-nanosecond and 100-nanosecond clock pulses.
The 27-MHZ clock is divided by 16 to become the
universal asynchronous receive/transmit clock. The
24-MHz and 16-MHz clocks are divided by two to
become the video format pixel clocks.
The control synchronizer also produces the
synchronization and timing signals for the three
tabular (text only) video formats.
formats are: 40
x 80 x 9 (40-line x 80-column x
width), 40 x 80 x 8, and 16 x 48 x 9.
SYSTEM MEMORY. The system memory
fiction consists of 512K of random access memory
(RAM) and 192K of erasable, programmable
read-only memory (EPROM). The RAM is used for
temporary data storage (file memory). The EPROM
contains the operational firmware required by the
C-DITEG. If the C-DITEG has field change 3
installed, the RAM is increased to 1M.
peripheral I/O (PIO) function interfaces the external
peripherals with the C-DITEG. The peripherals are
up to two hard-copy printer-plotters, up to six TV
monitors, up to six display control consoles (DCCs),
and up to two large screen displays (LSDs). The PIO
function also generates data and control signals for the
tabular video generator. The PIO function also
interrogates the display control consoles for any
switch actions. If a switch action has occurred, the
switch data is received from the DCC by the PIO,
reformatted, and transferred to the system computer,
via the system memory, by the I/O controller. The
PIO also sends the signals to control the lighting of
the lamps on the DCC control panels.
When a hard-copy printout is requested, the PIO
obtains the data from the video drawers bit mapped
memory, reformats the data for the printer-plotter, and
sends the data to the printer plotter.
formatted display data for the display control console
graphics display, large screen display, and the hard-
copy printer-plotter from file memory data. The
formatter also produces the control signals for the
function generator of the processor drawer and the bit
map memory of the video drawer.
FUNCTION GENERATOR. The function
generator creates display data consisting of conies
(circles and ellipses), vectors, and characters from
formatted data received from the formatter. This
display data is sent to the video drawer in the form of
pixel data for the generation of DCC and large screen