The latest connector technology fuels growth in embedded computing as system efficiency is a critical component for today’s embedded industry.
Regardless of the modern mobile application in question, whether it be fleet management of agricultural machines, passenger information in buses or video surveillance of trains, the trend is clear – system efficiency is a critical component to today’s embedded computing industry.
One of the key drivers in this area is the increase in visual data incorporated into embedded systems. Graphics mean higher throughput. Slide shows and short films are no longer sufficient; nowadays complex real-time 3D graphics or videos in HD quality are needed as well. Strong processors alone are not enough; applications like these require dedicated graphics hardware.
Grinding Through Graphics
Today, many chipsets have an integrated graphics controller and, therefore, are a good, cost-effective solution for small- and medium-sized system requirements. As a rule, the CPU and graphics controller share the main memory in this architecture.
When high resolution displays or even several screens with different, high-resolution visual content are to be controlled at the same time, the bandwidth of this shared memory reduces both the performance of the CPU and of the graphics unit. So, independent graphics controllers with an integrated video memory become the preferred option.
But if you choose an external graphics controller, the data transfer rate of the connection between the chipset and the graphics controller is the critical performance factor. For this reason, connector technologies have led the development of many of the modern buses.
First the PCI bus, then the AGP bus, and finally PCI Express were adopted for use with graphics cards, due to the need to efficiently and effectively connect the CPU with the graphics component.
Connectors Control the Flow
Data throughput is still at the forefront of connector technology, especially with the advent of high-speed serial connections quickly becoming the universally accepted data transfer route.
Contrary to other serial interconnects – such as SATA and USB 3.0, for example – PCI Express is not limited to a single lane (a differential receive and transmit signal line pair) but combines up to 16 of these lanes in parallel to control the graphics card (PCI Express x16).
Using this data transfer structure, the migration from legacy, parallel CompactPCI platforms to modern CompactPCI Serial-based ones became easier.
Graphics extensions are one reason for the new CompactPCI Serial architecture. Being just as robust and modular as its predecessor (CompactPCI), the new standard offers even more performance and serial interfaces. The CompactPCI Serial specification transfers the CompactPCI architecture to serial high-speed connections and offers better support for serial point-to-point structures.
A result of this enhanced specification was a newly introduced connector, specifically for CompactPCI Serial, that has, in turn, played an important role in the development of several embedded systems.
This connector scales to data rates of 12Gb/s and more without making space-wasting shields necessary. At the same time, it offers a much higher density than the conventional 2mm signal connectors typically usually used for CompactPCI.
To make sure that conventional CompactPCI interfaces like PCI Express, SATA, and Base-T Ethernet are not supplied alternatively but in parallel (meaning at the same time), connectors with high contact density on the system slot interfaces must be used.
Keeping Pace with Data Demands
The AirMax VS used in CompactPCI Serial offers an exceptionally high contact density of up to 184 contact pairs on a 3U board, enabling developers to use many free pins for customer-specific I/O interfaces on the peripheral modules.
The connector does not have special power supply pins and withstands a current load of 1A per pin at 85°C, with voltage supplied using standard connectors suited for signal transmission.
The connector’s mechanical design places the contacts individually, without thermal coupling. If one contact connection heats up more than another, the internal resistance increases, and the current finds its way over to cooler contacts. This guarantees that the load is spread equally over all contacts.
In CompactPCI Serial applications, connections between a front system or a peripheral board and the backplane are established using right-angled headers and vertical receptacle connectors. The interface to the rear I/O board uses right-angled receptacle connectors and vertical headers. The open design of the new signal connector offers flexibility in its contacts for differential or single-wire signals, grounding, or current.
New Connections Made
The specially-designed connector features enhanced thermal management properties and a rugged housing that combine to significantly increase reliability, enabling CompactPCI Serial to be considered for rugged applications not typically associated with its legacy specification.
But, the new connector type proved very useful in a new line of box and panel PCs from MEN Micro.
The uniqueness of this computing family, due in part to the connector, is that the external interfaces are separated from the main board. Depending on end-user requirements, many different versions based on the system core are possible. The connection to the system core is implemented without a cable and uses an AirMax VS connector for the high data rates required.
The electronic components are fully designed for demanding environments and even resist shock and vibration. Thanks to conduction cooling – in this case the housing of the box computer itself serves as the heat sink – the device operates at temperatures from -40°C to +85°C, according to the EN 50155 class Tx railway standard.
Increased Graphics Requirements
Functioning as independent computers, box PCs take on a variety of tasks in which graphics data becomes increasingly more important, and the connector needs to keep pace with data transfer demands.
Offering medium to high graphics performance, these computers are ideal as on-board computers or content servers. They can communicate with the control room via a wireless connection and send information to several displays. After all, DisplayPort supports HD resolutions of 1920 x 1080 pixels with a cable length of 45 feet.
Therefore, many applications in buses and trains are implemented using this type of box computer, making the ruggedness of the AirMax connector a critical feature to ensure reliable operation. A single computer controls, for example, two monitors in a bus via DisplayPort. They keep the passengers informed on the course of the route and display the stops and stop requests. In the meantime info videos are shown.
Whenever the train is in the depot, the data is updated via WLAN. The connector is constantly moving data from the external graphics platform to the main processing hub within the system.
Performance Reigns Supreme
Wherever higher performance is required, the scalable concept of these box PCs is of great benefit. AMD is way out in front of this concept at the moment. The Embedded G-Series combines each single- or multi-core CPU with a graphics processor of the Radeon range. These APUs (Accelerated Processing Units) make computing performance scalable thanks to their compatibility. A resolution of 2560 x 1600 pixels on several monitors is possible, even on devices suitable for vehicles.
Thanks to advanced connector technologies that keep pace with growing data demands, users have many possibilities to effectively employ enhanced graphics performance without the frustration of data bottlenecks. And by using standard components that can be flexibly integrated together, innovative ideas and technologies make cost-effective and robust graphics solutions possible.
About the Authors