One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106 • Tel: 781/329-4700 • Fax: 781/461-3113 • www.analog.com
10-Bit Interface Board for High Performance Display Interface Evaluation Boards
by Del Jones
INTRODUCTION
The purpose of the 10-bit display interface board (DIB)
is to aid in the evaluation of the AD9981 or AD9980. It
is designed to be used in conjunction with the evaluation boards for these parts, and is included as par t of
the evaluation board kits. It is a conduit for displaying
images on any flat panel monitor, CRT, LCD (or DLP)
projector, or TFT panel (with LVDS interface).
LIMITATIONS
The evaluation system using the 10-bit DIB is intended
to provide the user a platform with which to evaluate the
functionality and, to a limited extent, performance of the
AD9981 or AD9980. When evaluating the 8-bit AD9980,
the DVI or LVDS outputs of the 10-bit DIB offer the highest quality image for performance evaluation. However,
since both of these ports only offer 8-bit accuracy, they
cannot truly reflect the enhanced performance provided
by the 10-bit ADCs of the AD9981. The analog output of
the 10-bit DIB uses high accuracy 12-bit DACs and can
potentially offer a preferred interface for evaluation,
depending on the display device that is used.
PACKAGE CONTENTS
• An evaluation board for the AD9981 or AD9980
• A 5 V dc power supply
• A Centronix printer cable or USB A to B cable for
serial bus programming
REQUIREMENTS
In addition to the items included with the kit, the following items are needed to run this board:
• A computer with the evaluation software installed
• A 5 V dc power supply
• Any flat panel monitor, CRT, or projector 10-bit
display interface board
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Figure 1. Board Shown in Centimeters
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12
10
8
12
10
8
12
10
8
12
10
8
12
10
8
12
10
8
BLU A
BLU B
GRN A
GRN B
RED A
RED B
12
12
DAC
12
12
DAC
12
12
DAC
R
B
G
888888
LVDS XMIT
WITH CONNECTOR
POWER
VGA CONN
FPGA
[DATA DEMUX
(SINGLE PORT MODE),
DE GENERATION,
DE CONTROL, COLOR
CONVERSION]
TMDS
XMIT
DIGITAL RGB
AND SYNCS
FROM AD988x
PARALLEL
INTFC CONN
USB
INTFC
SERIAL INTERFACE
SYNCS
TO FLAT PANEL
MONITOR
OR
LCD PROJECTOR
TO CRT
OR
FLAT PANEL
MONITOR
DVI CONNECTOR
TO TFT PANEL
05441-002
EVALUATION BOARD HARDWARE
POWER
This board is designed to receive 5 V dc through connector J4. The power supply that is included in the kit plugs
into this connector.
BOARD FUNCTIONS
A block diagram of the 10-bit display interface board
is shown in Figure 2. The following sections briefly
describe these functional blocks.
DATA DEMULTIPLEXING
The Altera EP1C6QC240 FPGA (U6) performs most of
the logic functions on the 10-bit display interface board.
Among these functions is the demultiplexing of the
digital RGB data output from the AD998x when it is in
single-port data output (30-bit) mode (the AD9981 and
AD9980 are 30-bit only). The DVI and LVDS transmitters, as well as the digital-to-analog converters (DACs),
require dual-port digital RGB data. Therefore, demultiplexing is required when in single-port mode.
DE GENERATION
The DVI and LVDS interfaces require a data enable (DE)
signal which indicates when there is active image data.
Since the analog graphics signal does not contain DE, the
FPGA on the 10-bit display interface board is required to
generate it. The duration of DE is programmable via the
10-bit DIB register map of the display electronics (DEPL)
evaluation software and supports any display resolution
up to 4096 pixels 4096 pixels.
COLOR SPACE CONVERSION
The FPGA contains circuitry to perform color space conversion for 30-bit YPbPr data. This can be enabled via the
10-bit DIB register map of the DEPL evaluation software.
This can be used in conjunction with the midscale clamp
feature on the analog interface of the AD998x devices to
provide the proper colors for an YPbPr video signal. The
color space conversion also works with YPbPr signals
transmitted over the DVI interface. For the most accurate
color space conversion, the conversion results in a 12-bit
output for each of the digital RGB output channels. This
minimizes the rounding errors that can result from the
conversion process.
The 10-bit display interface board provides a DVI output
via SiI160 transmitter (U15) and DVI-I connector (J8).
This can be connected via DVI cable to any display
device (flat panel monitor or LCD projector) to display
any image from VGA to UXGA-60 (the SiI160 is limited
to 25 MHz to 165 MHz operation). Note that the SiI160 is
capable of processing only 8-bit data. Therefore, only
the 8 MSBs of the data output from the FPGA are used
for the DVI output.
LVDS OUTPUT
The 10-bit display interface board provides an LVDS
output via DS90C387 transmitter (U5) and LVDS data
connector (J9). This can be connected via user-provided
cable to any board flat panel with LVDS interface (such
as Samsung’s 21.3’’ UXGA panel, LTM213U3-L01-0, or
Sharp’s 18’’ SXGA panel, LQ181E1LW31) to display an
image using that panel’s native resolution. This interface
is capable of operating up to UXGA-75 (202.5 MHz). Note
that the DS90C387 is capable of processing only 8-bit
data. Therefore, only the 8 MSBs of the data output from
the FPGA are used for the DVI output.
ANALOG OUTPUT
The 10-bit display interface board provides an analog
output via high performance AD9753 DACs (U11 to U13)
and 15-pin VGA connector (J6). The AD9753 is a 12-bit
DAC that provides precision digital-to-analog conversion. Therefore, the analog output port is the best choice
to demonstrate the full 10-bit performance of the AD998x
devices. The analog output can be connected via VGA
cable to any display device (flat panel monitor, CRT, or
projector) to display any image from VGA to UXGA-75.
SERIAL BUS TO COMPUTER INTERFACE
(USB OR PRINTER PORT)
Some circuitry is needed in order to interface the AD998x
and the 10-bit display interface board’s serial register
interface with a computer. The 10-bit display interface
board provides both a USB and a parallel (printer) port
interface. The USB interface consists of a USB-B connector (J2), USB controller (U14), and an EEPROM (U16)
that contains board ID information. The circuitr y for the
printer port’s serial interface use U1 and U9, in addition
to the Centronix connector, J1.
POWER
The 10-bit display interface board has two voltage regulators that generate 1.5 V and 3.3 V for its own logic.
These voltages are regulated off of the 5 V input at J4.
The 5 V input is also routed to the AD998x evaluation
board interface connector (J3) to provide power for the
AD998x evaluation board.
EVALUATION BOARD CONNECTIONS
Figure 3 shows how the 10-bit display interface board
interfaces with the AD9981 evaluation board. It also
indicates the various connections needed to evaluate
an image.
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Figure 3. 10-Bit Display Interface Board with AD9981 Evaluation Board
–3–
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CONFIGURING THE BOARD
DE Generation
The VS_SEL (W15 on schematic) and HS_SEL (W16 on
schematic) jumpers allow you to choose raw VSYNC and
HSYNC or the VSOUT and HSOUT outputs of the AD998x
to generate DE. If the jumpers are placed between Pins
1 and 2 (closer to U2), the raw HSYNC and VSYNC are
selected. If the jumpers are placed between Pins 2 and
3, the sync outputs (HSOUT and VSOUT) of the AD998x
are selected. Either configuration works, although the
HSYNC and VSYNC delay values used for DE generation
vary slightly in each case.
PC Port Selection
The jumpers at W1 and W2 must be configured appropriately to use the desired PC port for software control. To
select USB, the jumpers must be placed between Pins 2
and 3. To select the printer port, the jumpers should be
placed between Pin 1 and Pin 2.
To USB Driver Installation
Follow these steps to install the USB drivers on your
PC:
1. Connect the board to the power supply.
2. Connect the USB cable from the PC to the board.
3. Windows sees the new device and asks to install
drivers for it.
4. Select Search for Drivers and click Next.
5. Specify a location and browse on the CD-ROM to
the USB Drivers\win2k directory.
6. Click Next and follow any remaining instructions.
7. If asked for any files, always browse to the same
USB Drivers\ win2k (or \win98) folder to find them.
DCLK Selection
The 10-bit display interface board is configured so that
the DCLK output of the AD998x drives the generation
of PANEL_DCLK and PANEL_DE. This is accomplished
through the placement of a jumper bet ween Pins 1 and
2 of Header W3.
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05441-003
EVALUATION BOARD SOFTWARE
The 10-bit display interface board (DIB) registers can be
controlled using the 10-bit DIB register map of the DEPL
evaluation software. This software is a Visual Basic®
program requiring a Windows® 95, or later, operating
system. It is on a self-installing CD package included with
the evaluation board (in the \DEPL Evaluation Software
subdirector y). The 10-bit DIB register map of the DEPL
evaluation software should be loaded into the \Program
Files\ADI Software directory upon completion of a successful installation.
Note : If a DriverX Install error is encountered during
the software installation, rerun the driverxinstall.exe
program located in the Program Files\Analog Devices\
DEPL Evaluation Software\ DriverX directory.
The 10-bit DIB register map can be accessed two ways.
From the menu bar, sele ct Device > 10 Bit DIB. The
10-bit DIB register map can also be accessed by selection
Tools > 10- Bit Display Interfa ce Board Conf igur ation. The 10-bit DIB register map is shown in Figure 4.
Using this screen, the user can control the features of the
10-bit DIB.
To implement the controls, click Load. This is true unless
the Load Register on Change box is checked or the Read
button is clicked. In this case, the registers are updated
as soon as any change is made in the window.
Register 01 controls the number of data clock cycles that
occur between Hsync and the beginning of DE. This is a
decimal number that is written to an 8-bit register. For
ease of use, a sliding bar is also included as an alternative method for controlling the Hsync delay. Moving the
bar to the right increases the delay and is reflected in
the box to the right. Moving the bar left decreases the
delay.
If using the DVI output of the 10-bit display interface
board, note that an image might not be visible until the
Hsync Delay is near the appropriate amount of delay
from Hsync to active video.
Vsync Delay (02–7:2)
Bits 7:2 of Regis ter 02 control the number of Hsync
periods that occur between Vsync and the beginning of
DE. This is a decimal number that is written to a 6-bit
register. A sliding bar is also included for Vsync delay
control.
LVDS/DVI Interface Enable (02–1:0)
Bits 1:0 of Register 02 serve as enable bits to turn on the
LVDS and DVI interface outputs of the 10-bit DIB. It is
recommended that these interfaces be powered down
when not in use.
Horizontal Resolution (03–7:04–4)
Horizontal resolution must be set using the 12 bits spanning Register 3, Bit 7 (MSB) to Register 4, Bit 4 (LSB).
The resolution is set in number of pixels by typing the
decimal number directly into the text box on the right or
by moving the scroll bar next to it. The maximum value
is 4096.
Vertical Resolution (05–7:06–4)
Vertical resolution must be set using the 12 bits spanning Register 5, Bit 7 (MSB) to Register 6, Bit 4 (LSB).
The resolution is set in number of lines by typing the
decimal number directly into the text box on the right or
by moving the scroll bar next to it. The maximum value
is 4096.
DE Settings for Interlaced Video (06–3:0)
When generating a data enable (DE) from an interlaced
video source, it is necessary to provide for an offset
between the odd and even fields. Bits 3:1 of Register 6
allow you to program the amount of offset (in number of
lines) between the two fields. Bit 0 allows you to select
how the even and odd fields are differentiated from each
other. The AD998x devices have an ODD_EVEN~ signal
that is routed to the 10-bit DIB’s FPGA and can be used to
determine the differentiation by setting this bit to a Logic
1. If using a device that does not provide this signal, the
FPGA generates its own signal to provide this function.
This signal can be selected by setting Bit 0 to Logic 0.
DE Select (07–7)
This bit allows you to select the source for data enable
generation. If the analog interface of the AD998x is being
used, Generated DE must be selected since the analog
interface does not include a DE signal. If the DVI interface of the AD998x is being used, either Generated DE
of Digital DE can be used. However, it is recommended
that the Digital DE be selected in this case.
Port Mode (07–6)
This bit allows the user to select the operating mode of
the AD998x. If the AD998x is operating in single-channel
(30-bit) output mode (the AD9981 and the AD9980 have
single-channel output only), single port mode must be
selected. If the AD998x is operating in dual-channel (60bit) output mode, Dual Por t (60 bit) must be selected.
DAC Frequency (07–5:4)
From the DAC Frequency Range menu, you can select
the operating range of the analog output. The 12 MHz to
100 MHz range should be adequate to display all resolutions XGA and above (including 720p and 1080p). For
lower speed resolutions, the appropriate range should
be selected.
Color Conversion Enable (07–3)
The color conversion enable bit allows you to turn on the
30-bit color space converter in the FPGA.
Half Clock Invert (07–2)
The bit allows the user to route the first pixel of demultiplexed 30-bit data to the even output por t of the FPGA
rather than the odd output port. The timing relation
between data and the data clock (PANEL_CLK_OUT)
remain the same. This bit is useful when centering the
image using the Hsync delay register.
PC Port Selection
To select between the USB and parallel ports for the
software interface click on the Options pull-down menu
and click on Device Interface and then select either USB
or Parallel. Refer to the PC Port Selection section for
further setup instructions.