In embedded PC applications, a key difference between products can often be in the BIOS firmware. Since the hardware is all based on similar silicon platforms, most currently available x86-based computer-on-modules (COMs) have similar hardware components. The x86 processor is the main performance booster.

The Northbridge, with its integrated graphics controller (GMCH), is responsible for memory bandwidth and graphics performance while the Southbridge (ICH) provides the connectivity through high speed buses like USB2.0, LAN, PCI Express (PCIe), PCI, SATA. If needed, legacy interfaces such as PS/2, LPT, COM and FDC are supported by the super I/O controller.

The combination of these four components is in most cases fixed and is basically comparable to the hardware features of a general purpose PC. There's little room for differentiation in basic hardware. That being the case, it's vital for embedded computing designs to have accompanying software that is fully functional and more versatile than what resides on consumer or office PCs.

So what makes a x86 BIOS an "embedded BIOS?" Together with the driver packages for common operating systems, the BIOS for an embedded computer module plays a key role in the overall system performance and stability. A COM vendor offering solid software and firmware is better focused on the higher demands of the embedded design world.

Obviously a BIOS for an embedded computing platform should have a basic feature-set equal to that found on the latest desktop, notebook, and server computers. However, unlike desktop and notebook computers, COMs are built into a variety of embedded systems, including point-of-sales terminals, telecommunication, medical, manufacturing automation and others.

Therefore, support for an open system architecture is mandatory for the BIOS used in a COM. Given this, the enumeration of the PCIe, PCI and USB bus, booting from USB mass storage and peripheral devices such as SATA, SCSI or LAN, enhanced ACPI power management as well as legacy USB keyboard and mouse emulation must all be considered when creating an embedded BIOS.

As any embedded designer will agree, demands for stability and reliability in embedded applications far exceed those required in desktop PCs. For example, it would be utterly unacceptable for a COM in a medical or industrial application to occasionally crash as desktop PCs do. So paying particular attention to BIOS features for embedded COMs is essential.

There are five key areas that make the difference between an average and truly effective embedded BIOS for a COM-based design. These include:

1) Industry leading AMIBIOS 8
2) On-board microcontroller
3) Special embedded BIOS features (details follow)
4) Customer application programming interface
5) System utility for BIOS binary modification

Look for these essential capabilities to find a highly-integrated firmware BIOS implementation that's well suited to embedded PC design applications. It is fundamentally important to start with a stable BIOS core supporting the latest industry standards and chipsets. Cutting corners in this area will create added costs later in the product design.

When selecting AMIBIOS8 from American Megatrends Inc., you are choosing the same proven BIOS core used by Intel's Embedded Communication & Platform Division (ECPD). AMIBIOS8 combines modularity, scalability and improved user experience in producing the most advanced BIOS solutions today.

AMIBIOS8 is well suited to embedded computer platforms because it offers many features demanded by the embedded market. Console redirection and BIOS flash update via serial port allow for real headless operation.

Although AMIBIOS8 offers support for the latest industry standards and technology, it still boots extremely fast from most initial program load (IPL) devices, including USB mass storage. In case of a power failure during an AMIBIOS8 flash update in the field, the BIOS can be recovered by using the boot block support.

Additional features offered by AMI such as TPM 1.2 support, headless operation and aggressive power management functions are also essential for embedded designs. In addition to its stability, the ability to adapt the AMIBIOS8 product to an application is what makes it ideal as a building foundation for an embedded BIOS.

Embedded PCs typically offer features not supported in a standard desktop or notebook BIOS. While on the other hand embedded PC designers have special requirements when it comes to BIOS functionality. These requirements need to be taken into account when designing additional embedded PC features like watchdog, I2C bus, OEM CMOS default settings, or flat panel auto-detection. PCs supporting these features can be considered to be real embedded PC products.