ADV7150LS135 AD [Analog Devices], ADV7150LS135 Datasheet - Page 13

• Manufacturer Part Number: ADV7150LS135
• Description: CMOS 220 MHz True-Color Graphics Triple 10-Bit Video RAM-DAC
• Manufacturer: AD [Analog Devices]

Color data is latched into the parts pixel port on every rising
edge of LOADIN (see Timing Waveform, Figure 3). The
required frequency of LOADIN is determined by the multiplex
rate, where:
f
f
f
Other pixel data signals latched into the device by LOADIN
include SYNC, BLANK and PS0–PS1.
Internally, data is pipelined through the part by the differential
pixel clock inputs, CLOCK and CLOCK. The LOADIN con-
trol signal needs only have a frequency synchronous relationship
to the pixel CLOCK (see “Pipeline Delay & Onboard Calibra-
tion” section). A completely phase independent LOADIN signal
can be used with the ADV7150, allowing the CLOCK to occur
anywhere during the LOADIN cycle.
Alternatively, the LOADOUT signal of the ADV7150 can be
used. LOADOUT can be connected either directly or indirectly
to LOADIN. Its frequency is automatically set to the correct
LOADIN requirement.
SYNC, BLANK
The BLANK and SYNC video control signals drive the analog
outputs to the blanking and SYNC levels respectively. These
signals are latched into the part on the rising edge of LOADIN.
The SYNC information is encoded onto the IOG analog signal
when Bit CR22 of Command Register 2 is set to a Logic “1.”
The SYNC input is ignored if CR22 is set to “0.”
SYNCOUT
In some applications where it is not permissible to encode
SYNC on green (IOG), SYNCOUT can be used as a separate
TTL digital SYNC output. This has the advantage over an inde-
pendent (of the ADV7150) SYNC in that it does not necessitate
knowing the absolute pipeline delay of the part. This allows
complete independence between LOADIN/Pixel Data and
CLOCK. The SYNC input is connected to the device as normal
with Bit CR22 of Command Register 2 set to “0” thereby pre-
venting SYNC from being encoded onto IOG. Bit CR12 of
Command Register 1 is set to “1,” enabling SYNCOUT. The
output signal generates a TTL SYNCOUT with correct pipeline
delay that is capable of directly driving the composite SYNC
signal of a computer monitor.
PS0–PS1 (Palette Priority Select Inputs)
These pixel port select inputs determine whether or not the de-
vice is selected. These controls effectively determine whether the
devices RGB analog outputs are turned-on or shut down. When
the analog outputs are shut down, IOR, IOG and IOB are
forced to 0 mA regardless of the state of the pixel and control
data inputs. This state is determined on a pixel by pixel basis as
the PS0–PS1 inputs are multiplexed in exactly the same format
as the pixel port color data. These controls allow for switching
between multiple palette devices (see Appendix 4). If the values
of PS0 and PS1 match the values programmed into bits MR16
and MR17 of the Mode Register, then the device is selected, if
there is no match the device is effectively shut down.
REV. A
LOADIN
LOADIN
LOADIN
= f
= f
= f
CLOCK
CLOCK
CLOCK
/4
/2
4:1 Multiplex Mode
2:1 Multiplex Mode
1:1 Multiplex Mode
–13–
Multiplexing
The onboard multiplexers of the ADV7150 eliminate the need
for external data serializer circuits. Multiple video memory
devices can be connected, in parallel, directly to the device.
Figure 13. Direct Interfacing of Video Memory to ADV7150
Figure 13 shows four memory banks of 33 MHz memory con-
nected to the ADV7150, running in 4:1 multiplex mode, giving
a resultant pixel or dot clock rate of 132 MHz. As mentioned in
the previous section, the ADV7150 supports a number of color
data formats in 4:1, 2:1 and 1:1 multiplex modes.
In 1:1 multiplex mode, the ADV7150 is clocked using the
LOADIN signal. This means that there is no requirement for dif-
ferential ECL inputs on CLOCK and CLOCK. The pixel clock is
connected directly to LOADIN. (Note: The ECL CLOCK can
still be used to generate LOADOUT PRGCKOUT, etc.)
CLOCK CONTROL CIRCUIT
The ADV7150 has an integrated Clock Control Circuit (Figure
14). This circuit is capable of both generating the ADV7150’s
internal clocking signals as well as external graphics subsystem
clocking signals. Total system synchronization can be attained
by using the parts output clocking signals to drive the control-
ling graphics processor’s master clock as well as the video frame
buffers shift clock signals.
VIDEO MEMORY/ FRAME BUFFER
VRAM (BANK A)
VRAM (BANK B)
VRAM (BANK C)
VRAM (BANK D)
PRGCKOUT
LOADOUT
SCKOUT
M IS A FUNCTION OF MULTIPLEX RATE
Figure 14. Clock Control Circuit of the ADV7150
LOADIN
CLOCK
CLOCK
BLANK
SCKIN
M = 4 IN 4:1 MULTIPLEX MODE
M = 2 IN 2:1 MULTIPLEX MODE
M = 1 IN 1:1 MULTIPLEX MODE
SYNC
33MHz
33MHz
33MHz
33MHz
24
24
24
24
ECL
TTL
TO
TO COLOR DATA
MULTIPLEXER
DIVIDE BY
MULTIPLEXER
N ( N)
ADV7150
N IS INDEPENDENTLY
PROGRAMMABLE
LATCH
ADV7150
ENABLE
N= (4, 8, 16, 32)
DIVIDE BY
ADV7150
24
M ( M)
(4 x 33 MHz)
132 MHz