Datex-Ohmeda D-VHC17, Technical Reference Manual

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Displays and Controller Boards
Document No. 8001004-1
11
2.4 Display Controller Board, B-DISP
B-DISP board is connected to the CPU Mother board. The processor on the CPU board transmits
program through the CPU bus to B-DISP board.
B-DISP board includes the functions of both B-DHIGH and B-DVGA boards . Thus, B-DISP board
supports both high resolution and VGA resolution. The resolution is automatically selected based
on monitor ID codes. The resolution is set to 640x480 if a VGA resolution display is used, otherwise
the resolution is set to 1984x512.
NOTE: S-ANE97/98/99, S-ICU97/98/99 and S(L)-ARK97/98/99 softwares support B-DISP, B-
DHIGH and B-DVGA boards. If, however, B-DISP board is used to drive D-VHC14 display, a small
part of the resulting picture will be clipped.
System memory
The system memory contains the GSP software code. The memory consists of two 256k x16
memory banks.
Frame memory
The frame memory contains digital display data. The size of the memory is 1 MB making 1984 x
512 display resolution with 256 colors possible. The memory consists of four 256k x 8 VRAM
memory circuits.
Video interface palette
The video interface palette reads the digital display data from the frame memory and converts the
data into analog RGB-signals. The synchronization signals for the conversion are generated by the
GSP.
The video interface palette is clocked by two pixel clocks. A 25 MHz clock is selected for VGA
resolution and a 40 MHz clock is selected for high resolution. The 40 MHz clock is internally
converted into a 80 MHz clock.
Graphics System Processor (GSP)
There are four 16-bit registers in the GSP, from which the host-processor reads and to which it
writes data.
Display Controller Resolution
The resolution of the display controller depends on initialization of the GSP's registers and
frequency of the video oscillator.
Reset Signal
Reset signal comes from the power supply unit through the CPU bus.