NCR 7460 User Manual - Command Descriptions
6-2
Chapter 6: NCR 7460 2x20 Customer Display
Command Descriptions
Structure/Logic Description
The 7460 integrated line display consists of a character generator
controller and display drivers. The CG Controller maps the character
value to a bitmap stored in memory. The controller outputs the bitmap
to the appropriate segment drivers for display. The display is 2 lines by
20 characters where each character is displayed lighting a 5 by 7
segment.
The display is controlled by a 7460 terminal motherboard through a
parallel interface.
Integrated Display Interface
The 7460 integrated line display connects internally to the terminal
motherboard. The display hardware interface is similar to a standard
parallel port interface. The display is logically connected to LPT2.
Standard parallel port drivers cannot be used since the standard
hardware connection is controlled in a non-standard way when
interfacing to the display. The display is controlled by writing either
Command or Data bytes through the parallel port to the display. To
display a character the character value is written as Data to the display.
The Character Generator controller writes the character bitmap to the
segment drivers of the display. The cursor position is updated by
either incrementing or decrementing to the next display data RAM
position.
Display Data RAM address 0 is the first character of the first line. The
last character address of the first line is 19. DDRAM address 64 is the
first character of the second line.