Physio Control LIFEPAK 9 - Page 42

LIFEPAK 9 defibrillator/monitor
Coded character address data used by the Font EPROM also loads into Video
RAM at this time.
ECG trace and messages display during raster scan. The Video RAM sends
ECG data to the Display Gate Array through EDAT(0-7); character address
information passes to the Font EPROM through DD(0-7). Character pattern
data stored in the Font EPROM is addressed and routed to the Display Gate
Array as CDAT(0-7). The Display Gate Array sends the character data out to
the proper address on the Display PCB (see Figure 1-8).
DISPLAY |
ADDRESS
000
001
2
COLUMN
FT
1FF 1+ Е
24 =
IXELS
>
E
P
m +
_
ROW
(256
PIXELS)
OSN
O
BU
ON
O
©
BO
O
ロ
ロコ
00 01 02 03 04 05 06 07 08 09 OA 0BOC OD CE OF 10 11 12 13 14 15 16 17 18 19 1A 18 1C1D1E 1F
COLUMN
768 PIXELS (768 VERTICAL RASTER SCAN LINES)
Figure 1-8 Character Cell Locations
The Display Gate Array also functions as a video intensity circuit, producing
four levels of brightness for the trace and characters. Two video outputs
from the Display Gate Array, Video 1 and Video 2, generate the appropriate
brightness level for the digitized display data by transmitting the data in a
two digit code to the Video Signal Amplifier circuit on the Monitor PCB.
This code determines if the addressed pixel will be at full intensity, normal
video, half-tone, or off (see Figure 1-9). Half-tone is used only for the
endpoints of the ECG waveform segments; full brightness is used only for
the sync marks. The rest of the ECG waveform and all the characters are
transmitted with normal brightness.
1-28 All Rights Reserved O August 1993 Physio—Control