The new Intel® Atom™ processor E6xx series offers a number of features that help developers reduce the cost and size of their products. One of the most significant features is the open chipset interface. Instead of the proprietary front side bus (FSB) used in past processors, the Intel Atom processor E6xx series connects to its chipset using one of the four PCI Express* (PCIe) lanes integrated into the processor. This open connection lets developers attach the processor to a variety of chipsets, including application-specific third-party chipsets, FPGAs, and ASICs. For applications with limited I/O needs, the Intel Atom processor E6xx series can even be used without a chipset. In this configuration, the processor’s four PCIe connections can attach to discrete PCIe peripherals such as Ethernet controllers.
This ability to customize the chipset can lead to significant cost and space savings because it allows the developer to select or design a chipset optimized for their application. To illustrate the benefits o a customized chipset, let’s start by examining the pros and cons of the standard chipset. The Intel Atom processor E6xx series is the first Intel® architecture (IA) processor designed specifically for embedded, and the chipset reflects this targeted design. As shown in Figure 1, the chipset, which is known as the Intel® Platform Controller Hub EG20T, includes a number of embedded-specific features like CAN and IEEE* 1588 rev2.
Figure 1. The standard chipset includes a considerable amount of embedded I/O.
Looking a bit closer, we can see that the standard chipset offers a solid set of I/O for displays, wired networking, storage, and connectivity. This I/O is a good match for some applications—digital signage and medical tablets are two examples that come to mind—but it is a poor match for other applications. As an example of the latter case, consider the needs of in-vehicle infotainment (IVI) applications. IVI applications typically need things like video inputs and copious GPIO, neither of which are offered in the standard chipset. Thus, you would need to supplement the chipset with one or more additional I/O chips. Conversely, the standard chipset includes things like Ethernet which may go unused in an IVI application. The bottom line here is that you could use the standard chipset in an IVI application, but it would be an inefficient solution.
This brings us around to the advantages of an application-specific chipset. Recognizing the limitations of a one-size-fits-all approach, Intel is working with several members of the Intel® Embedded Alliance to create application-specific chipsets for IVI, media phones, and other applications. One example of these chipsets is the Oki Semiconductor ML7213 shown in Figure 2. This chipset is designed specifically for IVI applications, and provides a more efficient solution for products that target that space.
Figure 2. The ML7213 chipset is optimized for IVI applications.
As noted earlier, another option is to skip the chipset altogether and connect peripherals directly to the processor directly via its four PCIe lanes. For solutions with limited I/O, this approach has obvious appeal, as it has the potential to cut the bill of materials (BOM) down to the bare minimum. However, there are some complicating factors to deal with before you can use the Intel Atom processor E6xx series as a stand-alone device. ADI Engineering has an excellent white paper on this topic, in which it points out the following design wrinkles:
- The Intel Atom processor E6xx series lacks an OS boot device interface such as SATA, PATA, SD, USB, or NAND Flash. Instead, the bootable I/O is located on the Intel Platform Controller Hub EG20T.
- The system management and power control hardware and firmware is complex and represents an added cost.
- Although it does not affect the hardware, the need for BIOS also adds to system cost and complexity. (The BIOS typically carries a per-unit royalty expense.)
ADI Engineering chose to deal with the first two complications by implementing a NAND Flash controller and a system controller/power manager in a CPLD. This approach enables remarkably compact, low-power solutions. For example, Figure 3 illustrates an 802.11n-to-HDMI streaming media device based on ADI’s hardware.
Figure 3. The ADI solution can be used to implement an 802.11n-to-HDMI streaming media device.
ADI and Intel worked around the BIOS issue by creating a royalty-free boot loader, cutting system costs substantially. It is important to note that the boot loader is not a full replacement for a BIOS. Among other things, it cannot be used to load Microsoft* Windows* Embedded Standard 7, nor does it offer the extensive configurability, control, and user interface of commercial BIOS offerings. However, the boot loader is sufficient to get a low-cost system running with Linux* or a real-time operating system (RTOS).
In short, the new Intel® Atom™ processor E6xx series offers a number of options for cost and size optimization. The ability to choose between the standard chipset, an application-specific chipset, or no chipset at all is a particularly important option. As the platform matures, I anticipate that we will see even more options in this area.
ADI Engineering is an Associate member of the Intel® Embedded Alliance.
Roving Reporter (Intel Contractor)
Intel® Embedded Alliance
Embedded Innovator magazine