TECHNOLOGY IN CONTEXT
choice of processors. The established PCI Industrial Computer Manufacturers Group (PICMG) COM Express form factor is offered for high-end platforms. Although two graphics interfaces (VGA and LVDS) were sufficient for the first COM Express modules, additional digital interfaces were added in the latest revision of the specification. With the shift from Type 2 pin-out to Type 6 pinout in the new COM Express profile, up to three digital display interfaces are supported in addition to fast USB 3.0. Digital display interfaces, especially DisplayPort (DP), have basically replaced analog interfaces. However, due to compatibility issues, VGA has not yet been completely eliminated. An additional embedded DisplayPort (eDP), which optionally can also carry low-voltage differential signaling (LVDS), is provided for a device internal display. DisplayPort (DP), specified by the Video Electronics Standards Association (VESA), is an interface for the transfer of audio and video signals between processor and display. Image data with a resolution of up to 4096 x 2160 pixels at a frame rate of 60 full frames per second can be transferred using DP. 3D applications with full HD images at 120 Hz are also possible. The usable resolution is, for the most part, independent of the cable length. The maximum data rate of DisplayPort (DP) is 5.4 Gbit/s. Systems that can drive multiple independent displays from a single CPU module can be built using the additional digital display interfaces. No external components such as an external graphics card are necessary for these solutions. This reduces costs and facilitates streamlined system integrations. At the same time, the long-term availability of the devices, which is still a problem for graphics cards, is improved. In principle, only three full HD monitors can be driven from the three DisplayPort (DP) interfaces. However, in many cases—for example, building a 2x2 video wall—it is better to be able to connect four independent HD displays together (Figure 1). Furthermore, multi-monitoring applications with four displays are rapidly gaining importance. For example, processes can be visualized on one screen, and camera images, status indicators or
a Windows application displayed on the other screens. Alternatively, it is also possible to drive a 4K monitor with a resolution of 4096 x 2160 pixels. A high-performance COM Express processor module (Figure 2) in compact form factor, based on AMD’s Embedded R-Series Accelerated Processing Unit (APU), can be used to drive the HD displays. The APU features very powerful graphics and high parallel computing performance with low power dissipation. Although only three DisplayPort (DP) outputs are available, four independent full HD displays can be driven— without an external graphics card. Several possibilities for the realization are, in principle, available. First, thanks to the multi-stream transport (MST) technology, a DisplayPort (DP) hub mounted on the carrier board or mounted externally delivers two separate streams for the two monitors. Onboard mounting of the MST hub obviously increases the system costs. The remaining two outputs (DP0 and DP1) continue to deliver DisplayPort (DP), High-Definition Multimedia Interface (HDMI) or Digital Visual Interface (DVI). Another option is the use of a DisplayPort (DP) daisy chaincompatible monitor. The display is connected to the DP2 output and also drives the fourth monitor.
FIGURE 2 The MSC C6C-A7, a COM Express Type 6 high-performance module family in a compact form factor, is based on AMD’s Embedded R-Series Accelerated Processing Units (APUs).
The third solution is achieved without additional hardware or special monitors. Three DVI monitors are driven directly via the three digital ports. A fourth display uses part of the multi-functional PCI Express x16 signals (PEG) as DVI port (GFX connections in Figure 3). At least two of the displays must have the same resolution, otherwise the effort required for the special graphics driver will be too complex. The latter cost-optimized solution is implemented in MSC Embedded’s highperformance MSC C6C-A7 COM Express module family, based on AMD’s Embedded R-Series Accelerated Processing Units (APUs) with quad-core or dualcore processors. By means of MPEG4-, MPEG2- or H.264-decoding, two full HD video streams can be decoded simultaneously. A video compression engine (VCE) accelerates the encoding of HD video streams and enables real-time transcoding. By mounting additional, external graphics cards for driving four or six monitors, up to ten displays can be driven with the Computer-on-Module (COM). AMD Eyefinity technology is a solution developed by AMD that supports the drive of multiple displays using a single enabled AMD R Series APU. This technology is now available on a COM Express compact form factor. Eyefinity allows the connection of six independent display contents on just one graphics processing unit (GPU). Due to the simple configuration and flexible upgrade possibilities, the monitors can be used in various landscape and portrait modes. Thanks to the software, for example, the distortion that occurred with video walls caused by the monitor frames can simply be “calculated out” and thereby compensated for. For applications with vast amounts of data—for example, high resolution image acquisition— besides the CPU cores, the high-performance arithmetic units of the graphics controllers can be used for floating point, vector and image processing tasks. This is possible thanks to uniform programming for various high-performance hardware architectures through the vendor-independent, non-proprietary programming platform Open Computing Language OpenCL. OpenCL is an open and royalty-free programming standard maintained by the
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