9.3 Using a COTS Board

The acronym Commercial Off The Shelf (COTS) is often used in the embedded industry to indicate a product that is available commercially and can be used by multiple customers for their applications. Vendors such as Force Computer, Radisys, and Embedded Planet offer COTS boards for use by various vendors, including communications equipment manufacturers. Some equipment vendors integrate these boards into their own designs as-is, while others use these as an interim platform for development before the final hardware is ready. Our discussion will focus on the second scenario.

Assume that the final hardware platform for the IPS is a single-board, single-processor system using a Motorola PowerPC 750™, running VxWorks™. It will have 4 Ethernet ports and 2 Frame Relay (WAN) ports. The hardware designers will work on a cost- efficient design for the hardware, deciding on the components needed on the main board and via add-on cards. Details of the design vary based on the market and cost requirements. In the meantime, software developers can develop and test the IPS software on a COTS board using a PowerPC 750 processor running VxWorks. It is not likely that the COTS board will have the same number of interfaces required by the final hardware design, but it is a good platform to verify application functionality.

Using the COTS board lets engineers build the software using the same development environment and set of tools that will be used on the final target. This includes the compiler, linker, debugger, and the RTOS itself. Issues related to the processor and hardware can be sorted out during this phase. Since the COTS board often includes add-on PCI slots, developers can purchase COTS add-on cards (e.g., a PCI-based dual-port T1 interface for Frame Relay) and test the product extensively. Similarly, some security chip providers offer a validation platform for their chips using PCI cards that can run under VxWorks or Linux. These validation platforms can be added to the COTS board and used to verify the functionality of the silicon in the IPS environment as well as the performance of the IPS, using the security processor before its design into the final target.

Since the hardware interface support on the COTS board may be limited, developers need to maintain conditional compilation flags for those parts of the code baseline which depend on the hardware, such as a constant defining the number of hardware interfaces on the target. An include file specifying this variable would have the format shown in Listing 9.1.

Listiing 9.1: COTS board include file.

#ifdef COTS_BOARD    #define NUMBER_OF_HARDWARE_PORTS     4 #else    #define NUMBER_OF_HARDWARE_PORTS 6 #endif

Teams need only a few COTS boards for development since these boards have limited use once the final target is ready. The boards can also serve as good validation platforms and, in some cases, as good demonstration platforms at trade shows or for early adopter customers wanting a proof-of-concept platform.