RTC Magazine

The trend we have been witnessing over roughly the past nine months of integrating FPGAs with embedded processors for custom I/O functionality, just got another validation with the entry of Intel. Originally code named Stellarton, Intel’s entry consists of a series of modules featuring an Atom E6xx processor (formerly code named Tunnel Creek) combined with an Altera Arria II GX FPGA. The two devices are mounted on a 37.5 mm x 37.5 mm, 0.8 ball pitch module with two PCI Express x1 lanes connected to a hard-wired PCIe link on the FPGA.

The Intel introduction differs from previous devices introduced by Actel—now merged with and under the brand name of Microsemi—and Xilinx (see The Application Services Platform: A New Class of Devices for Embedded Development and Systems, RTC April, 2010, p. 12). In the previous two cases, FPGA manufacturers integrated ARM processors with their own FPGAs. Intel is the first CPU vendor to bring in an FPGA to integrate with its device. This may or may not make a difference, but it will be interesting to see how the perspective of the processor company influences the character of the part. We have noted in previous coverage of this area that there are potentially many approaches and many application areas that will benefit from those approaches.

In the case of Microsemi (especially), and Xilinx as well to a certain extent, there is a goodly amount of preconceived functionality installed on the FPGA portion from the beginning. The Microsemi SmartFusion, for example, has a big slant toward analog processing already built in. The Xilinx effort looks like it will also have a certain amount of A to D and a few other I/O functions preinstalled. Of course, the customer can always alter what is in the programmable section. In addition, the ARM-based examples also include a number of standard peripherals in the CPU section of the design. The Atom portion of the E6x5C series integrates such things as display control, graphics processing, memory control and audio on the CPU die as well (Figure 1).

The Intel E6x5C series by contrast is not delivered with any preinstalled IP. That is left up to the OEM customer to install by means of Altera or third-party IP libraries or through the use of Altera’s Quartus II development tool. Lest this seem harsh, it should be noted that the E6x5C is only one option for the use of the E6xx Atom family. Intel designed the processor with a PCIe link to the outside world so that developers could take advantage of a variety of I/O options. Intel itself supplied an I/O hub that supports a range of common I/O interfaces such as GPIB, USB, PCIe, CAN, etc. Other hubs are coming to be available from third-party vendors with sets of interfaces targeted at specific areas such as in-vehicle entertainment or IP media.

In fact, it is also possible to use the E6x5C series with an I/O hub connected to the processor’s other external (2 x1) PCIe connection. The second PCIe connection can be used for anything including another I/O hub. The point of the FPGA is to offer flexibility and the ability to tightly integrate specialized, custom and proprietary I/O functionality without adding additional components. Such specialized I/O functions represent a good part of an OEM’s value add. In terms of flexibility, it is also straightforward to implement different product versions and variations with the same hardware inventory and often during the same production run simply by changing the IP in the FPGA.

Just how these new devices—and we predict there will be more and different variations from these and other vendors—will compare in terms of cost and performance is yet to be determined.  The E6x5C series is currently available in six version—three clock frequencies of 0.6G Hz, 1.0 GHZ and 1.3 GHz in two temperature ranges each—commercial 0° to 70°C and industrial -40° to 85°C. The current offering also still consists of two devices mounted on a small circuit board with a ball grid array on the bottom. Intel is not talking about future products but it would appear that the eventual integration of the two devices into a single IC package if not onto the same die would be a logical next step.

The E6x5C is already debuting on an OEM product, the Microspace ModuleST (MSMST) from Kontron (Figure 2). The MSMST is implemented on a PCIe/104 form factor, which also includes an interface to the High-Speed Mezzanine Card (HSMC), which is a specification from Altera meant to simplify interfacing I/O connections to its FPGAs. This is a part of the Kontron design and is not required by the Intel platform. In this iteration of the MSMST, the multimedia interfaces SVDO and HD audio are brought off to a separate media board along with a PCIe connection to Ethernet. So not only is the FPGA itself a support for flexibility and configurability, but so are the other external interfaces from the CPU die (Figure 3).

Figure 2
The Kontron MSMST module is implemented on a PCIe/104 board with a connector off the FPGA for attaching an Altera high-speed mezzanine card (HSMC).

Figure 3
Block diagram of the Kontron MSMST.

Kontron Product Marketing Manager Christine Van De Graaf notes that Kontron had already noticed that OEM customers were going around the I/O hub supplied by Intel and programming directly onto FPGAs—which is actually one of the options offered by Intel with the introduction of the Tunnel Creek parts. The availability of the E6x5C series with the FPGA pre-integrated and verified now makes that much easier and so it was a natural step to produce a ready-to-go platform that customers could use to get their proprietary IP up and running for their specialized needs. For example, there are apparently a number of specialized I/O functions in the transportation arena that were already being solved with FPGAs on separate modules connected to the SBC.

While Actel’s (now Microsemi’s) SmartFusion is now appearing in products, the Kontron MSMST appears to be the first OEM single board computer available in a standard form factor that developers can take and use to develop whatever application they have in mind and/or integrate it with other off-the-shelf modules to address a given set of needs. The E6x5C can support embedded Windows with a variety of BIOS options and is also offered by Intel with the support of the now Intel-owned Wind River MeeGo or VxWorks operating systems, making it as general-purpose a product as many other Atom-based modules with the added attraction of the programmable and configurable FPGA option.

The HSMC connection allows the developer to easily bring out the I/O connections of the FPGA package so that they can be connected to external devices. These connections can be routed to whatever IP the OEM or the customer has placed on the FPGA and then to the appropriate external connectors. In addition to the IP that can be purchased from libraries and can be developed from scratch using the Quartus II design tools, Kontron also offers a service through which they will help the customer develop that custom IP. Like Intel, Kontron has not installed any predetermined IP blocks in the FPGA, although that does not preclude any other vendor who may wish to from doing so.  

Altera
San Jose, CA.
(408) 544-7000.
[www.altera.com].

Intel
Santa Clara, CA.
(408) 765-8080.
[www.intel.com].

Kontron
Poway, CA.
(888) 294-4558.
[www.kontron.com].