Simplifying the embedded video interface

fanless computers, Panel PC, single board computer

The expectations for video quality continue to rise as more applications take advantage of video sources. Transmitting more video data at higher rates requires attention to a range of signal integrity issues summarized here.

Industrial video systems such as machine vision, surveillance equipment, and medical displays face a myriad of challenges transporting high-resolution video data from source to processor or display.

Current solutions such as Camera Link, GigE Vision, and other LVDS interfaces have served the industrial market quite well, but are now encountering obstacles associated with reliably transmitting higher-speed data over long cable lengths. Increased EMI often accompanies higher switching data rates. Also, there is the constant desire to minimize both system cost and design complexity.

The following discussion will examine the design challenges associated with moving to higher data rate embedded video interfaces and present several solutions.


Let’s start by looking at a few common applications. Machine vision systems require the transfer of captured image data from a digital camera to a remote frame grabber. The rate of data transfer is influenced by the resolution, bit depth, and frame rate of the image capture. Higher-resolution and bit-depth images are designed to provide the detail required for complex analysis. This is critical for uses such as electronics inspection equipment, where the geometries are shrinking and necessitating more detailed examination. Faster frame rates are desirable to improve overall inspection throughput.

Today’s machine vision systems typically employ the communication interface specified by the Camera Link standard. Published in October 2000, this standard has successfully supported the vision industry for years. The interface consists of parallel differential pairs of serialized data (7:1 ratio), as well as a parallel differential clock. Figure 1 illustrates a common Camera Link interface.


fanless computers, Panel PC, single board computer
Fanless Computers, Panel PC, single board computer


The 7:1 serialization scheme over LVDS provides efficient, robust communication for many applications. However, there are some limitations and challenges when scaling the technology to higher throughput and longer distances. The parallel nature of the differential clock and data pairs (diagrammed in Figure 2) is susceptible to excessive pair-to-pair cable skew when the clock rate and distance increase. Because a separate clock channel is used to sample data at the Camera Link receiver, it is important to maintain the proper setup and hold relationship between the two. As the interconnect length increases, the inter-pair skew increases, possibly exceeding the margin. High-grade and more expensive cable and connector solutions might be required to minimize the skew.


fanless computers, Panel PC, single board computer
fanless computers, Panel PC, single board computer


Similar challenges face industrial display systems, where the link is between an image source (an imager or graphic controller) and a digital display. As with vision systems, there is a drive to increase data rates and support higher color depth up to true color at 24 bits per pixel. More significant is the move to HD resolution and beyond, providing useful detail for surveillance and medical applications. Parallel LVDS solutions similar to those used by Camera Link experience the same type of cable skew limitations. As the data rates increase, skew margin is further reduced and maximum cable length decreases.

Using an embedded clock interface eliminates this inter-pair skew limitation. All data and clock are encoded and serialized for transmission over a single differential pair such as shown in Figure 3. The deserializer receives the serial stream and uses a clock and data recovery circuit to extract the clock and data signals.


fanless computers, Panel PC, single board computer
fanless computers, Panel PC, single board computer


In addition to removing skew concerns, a serialized solution provides several other advantages. Driving only one differential pair reduces the overall size of the interconnect media. This means smaller cables and connectors can be used, minimizing connector footprint area on the PCB and allowing a narrower and more flexible interface. Reducing the number of pairs in the cable assembly and removing the restriction for tight skew tolerance enables the use of lower-cost cables.

Moving to a serialized interface can have a positive impact on system design. However, some considerations must be addressed when designing with an embedded clock scheme. First, designers must consider the fact that the data rate on the differential pair is now much higher. Data that was once transmitted over four pairs is now sent on only one pair – approximately a 4x increase in data rate.


Other design considerations are associated with higher interface speeds, along with the array of features and techniques available to ease design and enable robust and cost-effective solutions.

At these higher data rates, signal integrity becomes more critical. Designers are no longer concerned with the alignment of clock and data, but rather with the eye opening of each bit within the serialized data stream. As data traverses the cable, the signal is degraded due to the effects of attenuation, jitter, and Inter-Symbol Interference (ISI). To be received correctly, it is important that the data eye be open at the end of the cable – the input to the deserializer.

Cable equalization and de-emphasis are two features targeted at combating signal degradation. The effect of equalization is to reopen the differential signal’s data eye at the far end of a cable, as illustrated in Figure 4. An equalizer applies a high-pass filter and gain curve that is inversely proportional to the cable’s attenuation curve. The ability to program the equalizer’s gain allows for tuning to optimize performance with different cables and lengths. This circuit can be discrete or built in to the deserializer’s input.


fanless computers, Panel PC, single board computer
fanless computers, Panel PC, single board computer


The second technique, signal de-emphasis, combats the effects of ISI. Depending on the data pattern being transmitted, a charge might build up on the cable. This impedes the ability to quickly switch to the opposite state. ISI results in the loss of signal amplitude and is especially apparent when sending a single bit, for example, a single one in the midst of a long string of zeros. The energy of this single-bit transition is not enough to offset the charge stored in the cable, thus a closed eye appears at the deserializer’s input.

De-emphasis (with effects shown in Figure 5) reduces the output voltage driven on the line after the initial transition is complete. This minimizes charge buildup on the cable and the associated DC offset and allows the signal to easily transition to a new state. The level of de-emphasis should be adjustable such that the effect can be optimized for interconnect characteristics.


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Figure 5: The eye opening at the end of a 10 m cable is shown without de-emphasis (left) and with de-emphasis (right).



A challenge common to all systems, whether using a traditional or serialized interface, is EMI reduction. As resolutions and color depths increase, the edge rate and number of channels switching increases, resulting in increased emissions. This can be attacked on several fronts, starting with LVDS and its widespread use. LVDS has a common parallel video interface (four data pairs and one clock pair) and is used in serialized embedded clock solutions.

However, the connection to the source and sink devices (frame grabber or display) might use an LVCMOS interface. Wide parallel LVCMOS output buses are notorious as emissions hot spots. It is important to try to minimize the energy related to these outputs switching and to spread the spectrum of this energy where possible. As parallel outputs switch faster, the edge rates need to increase. Output transitions should be as slow as practical to support the required switching frequency and output loading. Deserializers with programmable output drive provide this flexibility.

Spreading the spectrum of energy is a common practice to reduce peak emissions. In some cases, a source might provide a spread-spectrum clock. The selected serializer and deserializer should be capable of tracking this clock modulation to gain the most benefit. Spreading at the source might not always be supported, so it is desirable to use a deserializer that can generate its own spread-spectrum output, targeting emission reduction at the output hot spot.

Even when using chipsets with EMI reduction features, it is critical to follow sound PCB design practices.


National Semiconductor’s Channel Link II family of SERDES chipsets is designed to simplify the implementation of serialized video interfaces. A maximum clock frequency of 75 MHz enables HD 720-pixel video. Up to 24 bits of data, accompanying video synchronization signals, and video pixel clock are serialized to a single low-voltage differential output.

The chipsets provide adjustable de-emphasis and equalization for signal conditioning. A proprietary DC balanced encoding scheme, along with data randomization and scrambling, minimizes ISI and reduces emissions on the link, spreading the spectral content that would otherwise be present with a repetitive pattern. Both serializer and deserializer are designed to take advantage of spread-spectrum clocking from an upstream device, as well as provide a self-generated spread-spectrum clock. Additional EMI reduction features include reduced drive strength and staggered switching of parallel output drivers. All parts offer an auto-sleep power-reduction feature, shifting into a low-power mode when input interfaces are inactive.

Parallel bus connections with LVCMOS or LVDS (four data plus one clock) are available. This LVDS interface is equivalent to National’s 28-bit Channel Link product and provides an easy-to-use upgrade path where image source, frame grabber, or display controller include integrated LVDS.

For systems that require higher bandwidth and longer cable drive (compared in Figure 6), National’s FPGA Link solution is an ideal fit. Coupled with cost-effective FPGAs at the sink and source, data rates up to 3.125 Gbps can be achieved over 30 m of cable. The deserializer features a re-timed serial output to drive daisy-chained sinks, which is especially useful in tiled display applications.


fanless computers, Panel PC, single board computer
Figure 6: Different serialized video interfaces meet varying needs for bandwidth and cable length.


Embedded video systems can realize advantages in both performance and cost through the use of a serialized interface. Solid design practices and techniques are important for successful implementation. National’s Channel Link II and FPGA-Link chipsets provide a serialized interface with signal conditioning to minimize skew concerns and allow the use of longer and narrower cables. EMI-reduction features and compatibility with various source and sink devices offer easy-to-use and robust solutions.


Embedded computing needs

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Understanding and selecting analog IP can be risky, but engineers today have more choices and more control than they think. Knowing how to manage the IP selection process can help engineers effectively meet objectives and reduce risk.

As digital design has proliferated the electronics world, making designs faster, easier to test, and more robust, the analog portion of embedded designs is becoming a bottleneck. To meet requirements and timetables in the analog portion, engineers generally have three weapons at their disposal: utilize peripheral analog IC, build the functionality internally (make), or purchase the IP block from an external vendor (buy). Each option has its own merits and drawbacks, but none can launch a competitive advantage better or cause more frustrating confusion than analog IP.

Traditionally, these options only apply to ASIC builds, as FPGAs are not compatible with analog IP. However, this is changing quickly. Some IP companies now provide all Register Transfer Language (RTL)-based Analog-to-Digital Converter (ADC), Digital-to-Analog Converter (DAC), DC-DC converter controller, and clocking functions with robust performance.




3.5 inch embedded single board computer with Atom N2800

industrial computers, Panel PC, single board computer

AMB-N280S1, which carries Intel dual- core 1.8 GHz Atom Processor N2800. acrosser takes advantage of Atom Cedar Trail N2000 series processor in design, such as low power consumption and small footprint as former Atom series.

Intel Atom Processor N2800 provides more powerful graphic performance by less power consumption. AMB-N280S1 can support both two displays to maximum resolution 1920 x 1200. It also offers the 18-bit LVDS interface for small size LCD panel.

Powerful Intel® Atom™ processor to keep you going

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Tablets featuring the Intel® Atom™ processor are power optimized to keep up with you and not slow you down, and allow you to listen, watch and play without worrying about battery life. 



Intel Celerons processor include power-saving features

 Intel Celeron Dual-Core processor family is the latest generation of Celeron-branded budget microprocessors. The family was introduced in January 2008, and currently consists of 7 desktop and 9 mobile microprocessors. The Celeron Dual-core family is based on Core microarchitecture, and includes all basic Core features:

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Intel 3rd Generation Core i7-3615QE BGA processor ACM-B6360

industrial computers, Panel PC, single board computer

ACM-B6360 is base on COM Express Type 6 pin-out design and supports two DDR3-1333 SO-DIMM socket with ECC and four native USB 3.0 ports.

The ACM-B6360 carries on board Intel 3rd gnenration Core i7-3615QE FCBGA1023 processor which supports three independent display with multiple output : 24-bit LVDS, VGA, HDMI and one DDI interface. One PCI-E x16 Gen., 3.0 and seven PCI-Ex1 interfaces for IO expansion.

Key features:

1. COM Express Basic Type 6 Module with Fan heatsink
2. Onboard Intel 3rd Generation Core i7-3615QE BGA processor.
3. Two DDR3 SO-DIMM sockets with ECC supportted, up to 16G
4. Supports 3 independent display output
5. 1 x PCI-E x16 Gen.3, 7x PCI-E x1 interfaces
6. 2 x SATAIII ports, 2 x SATAII ports
7. 4 x USB 3.0 ports, 4 x USB 2.0 ports
8. 1 x GbE, I2C, SMBus, LPC interface

Intel D2550 Processor with NM10 Chipset AMB-D255T1

acrosser launches new slim Mini-ITX mainboard with Atom D2550, DDR3, HDMI, GbE, COM for Digital Signage and POS application.

Acrosser Technology Co. Ltd, global professional industrial and embedded computer provider, announces the new Mini-ITX mainboard, AMB-D255T1, which carries the Intel dual- core 1.86GHz Atom Processor D2550.

AMB-D255T1 features powerful graphic performance via VGA and HDMI, DDR3 SO-DIMM support, mSATA socket with USB signals and SIM slot, and a DC jack for easy power in. AMB-D255T1 also provides complete I/O such as 4 x COM ports, 6 x USB2.0 ports, 1 x GbE RJ-45 port, 1 x SATA port with power connector.


embedded computers ,Panel PC ,single board computer
Embedded Computers ,Panel PC ,single board computer

.Intel Atom D2550 1.86GHz
.1 x DDR3 SO-DIMM up to 4GB
.1 x VGA
.1 x HDMI
.1 x 24-bit LVDS
.6 x USB2.0
.4 x COM
.1 x GbE (Realtek RTL8105E)
.1 x PS/2 KB/MS
.1 x MiniPCIe slot
.1 x SATA with power connector
.8-bit GPIO

Fanless Panel PC for HMI and Industrial Automation applications.

AR-P190FLDC-D52 is designed with Intel Dual Core Atom D525 CPU and Intel ICH8M platform, 19” resistant touch screen, front panel IP65 and fan-less operation, made it suitable for the KIOSK and other applications.

AR-P190FLDC-D52 has the features as touch screen, 19-inch TFT LCD monitor of 1280x1024resolution, built-in DDR3-800 2GB SO-DIMMs, 320GB 2.5-inch hard drives, internal / external CF slot. 1 x RS232 port, 1 x RS422/485 port, 4 x USB ports and two RJ45 network connectors. You also can have the option of a internal wireless WiFi module with external antenna.


embedded computers ,Panel PC ,single board computer
Embedded Computers ,Panel PC ,single board computer


The AR-P190FLDC-D52 with high-quality and high-reliability is ideal product for industrial automation, Point of Sale (POS), In-vehicle systems, digital signage, gaming and multifacetedmarket requirements.



AR-B5630 which carries the Intel ATOM N450 Chipset

With Intel GMA X3100 graphics core built in the Intel GME965 chipset support dual display, CRT and LVDS, or DVI (TV out).

The great graphic performance fulfilled most application demands save add on display card. The great flexibilities of dual display combinations make ease to gather variety of display devices together what ever new or old or different interfaces but work fine together.

AR-B5630 features 4 USB ports (2 onboard and 2 internal), 4 high speed RS-232 (one of them can be set as RS-422/485), dual Giga LAN, 1 x IDE, 1 x SATA, 5.1CH audio, 8 bit GPIO, PS2 KB/MS and one Compact Flash Type II Socket

embedded computers ,Panel PC ,single board computer
Embedded Computers ,Panel PC ,single board computer

1. Socket P support Intel Core 2 Duo/Celeron M
2. Support 400/533/667MHz DDR2 SDRAM
4. Dual Giga LAN
5. PCI-104 Expansion
6. COM, USB2.0, GPIO, SATA, IDE, CF II, Audio

Embedded 3.5 Inch SBC with Intel Atom

acrosser Technology Co. Ltd, global professional industrial and Embedded Computer provider, announces the new 3.5” SBC, AMB-N280S1, which carries the Intel dual- core 1.8 GHz Atom Processor N2800.

Intel Atom Processor N2800 provides more powerful graphic performance by less power consumption. There is one HDMI port and one VGA output on AMB-N280S1 can support both two displays to maximum resolution 1920 x 1200. It also offers the 18-bit LVDS interface for small size LCD panel. There are two Mini-PCIe expansion slots for customer’s expansion. One on the upper side comes with SIM card socket, PCIe signals, and USB signals that can be equipped with 3G/4G telecommunication module. The other one on the bottom side is designed with SATA signals especially for mSATA storage module.


For more product information, please visit Acrosser product pages.’’-SBC/AMB-N280S1/Single-Board-Computer-AMB-N280S1.html