adv7152 Analog Devices, Inc., adv7152 Datasheet - Page 27

• Manufacturer Part Number: adv7152
• Description: Cmos 220 Mhz True-color Graphics Triple 10-bit Video Ram-dac
• Manufacturer: Analog Devices, Inc.

Palette Priority Select Inputs
The palette priority selection inputs allow up to four separate
palette devices to be used in a single system to drive a single
monitor. The IOR, IOG and IOB analog video output signals of
each device are connected together, as shown. Signal inputs
(PS0, PS1) determine on a pixel by pixel basis which palette
device drives the monitor. This allows for implementation of
multiple windows applications with each device acting as an
independent palette. During initialization, each device is as-
signed two match bits, MR16 (PS0) and MR17 (PS1) in Mode
Register MR1. PS0 and PS1 inputs will select one of the prepro-
grammed devices at any instant when PS0, PS1 matches MR16,
MR17, respectively. When PS0 and PS1 do not match these
bits, the DACs of the particular device are shut down, driving
RGB outputs to 0 mA. PS0 and PS1 are multiplexed similar to
the pixel data, thus allowing for subpixel resolution. The dia-
grams show an example of one ADV7152 operating in conjunc-
tion with three ADV7151’s (Pseudo-Color RAM-DACs). Each
displayed window on the monitor is driven by one of the four
devices. Each device’s analog output signals are connected to-
gether as shown.
REV. B
PS0, PS1
G0–G7
R0–R7
B0–B7
P0–P7
PALETTE SELECT BITS
PALETTE SELECT BITS
PALETTE SELECT BITS
PALETTE SELECT BITS
ADV7151 (3)
ADV7151 (2)
ADV7151 (1)
MR16 MR17
MR16 MR17
MR16 MR17
MR16 MR17
ADV7152
0
PALETTE
0
PALETTE
1
PALETTE
1
256 x 30
256 x 30
256 x 30
Multiple Devices Driving a Multiwindow Application
256 x 30
RAM
0
0
1
1
MULTIPLE PALETTE APPLICATIONS
ANALOG
ANALOG
ANALOG
ANALOG
VIDEO
VIDEO
VIDEO
VIDEO
RGB
RGB
RGB
RGB
APPENDIX 4
VIDEO TO MONITOR
–27–
Note: Only one palette device is selected at any particular
instant. The analog output levels of the unselected devices will
be 0 mA.
Other applications for the palette priority function using a mini-
mum of two devices (two ADV7152s or one ADV7152 and one
ADV7151) include:
Cursor Overlay on 24-Bit Graphics
Active Live Video Overlay (from Frame Grabber)
Text/Character Generation and Overlay
(DEVICE: 2)
(DEVICE: 1)
DACs
DACs
Multiple Devices Termination for a Single Monitor
IOR, IOG, IOB
IOR, IOG, IOB
TERMINATION)
Z
PS0 = 0: PS1 = 1
(Pseudo-Color)
(SOURCE
S
WINDOW 1
= 75
TRUE-COLOR BACKGROUND
PS0 = 1: PS1 = 0
(Pseudo-Color)
WINDOW 2
PS0 = 0: PS1 = 0
MONITOR
Z
(CABLE)
O
PS0 = 1: PS1 = 1
(Pseudo-Color)
=75
WINDOW 3
ADV7152
Z
(MONITOR)
L
= 75