Connectivity platforms answer the device networking call

By Adrian Braine Oxford Semiconductor

As devices get smarter, they must participate in more and more networks. Simple serial ports can no longer handle the task. System-on-Chip (SoC) platforms are arriving with integrated processing, networking peripherals, and Operating System (OS) and driver software, making the job of adding networking to an industrial device straightforward. Here’s one example of this new class of SoCs.

The role of device networking products has become critical to the operation of electronic systems in a wide variety of different sectors. Factory automation, Point-Of-Sale (POS), building management, and many other applications have evolved rapidly to benefit from the adoption of device networking architectures.

The sheer number of devices in these applications is increasing exponentially, and all offer valuable data that users must harvest and utilize to enhance decision making and improve efficiencies. However, many of these devices are relatively “dumb” and low cost, and as a result have only simple interfaces such as serial RS-232/485.

At the same time, system designers want to leverage Ethernet’s capability to shift the device data to a central server (and onwards to a global network). Thanks to the IT fraternity, many sites will already be kitted out with CAT5 cabling, making its use as a control and communications infrastructure even more desirable. More recently, the advent of deterministic Industrial Ethernet has removed the final barrier to Ethernet’s complete adoption by opening it up to applications where latency is critical.

Shown simplistically in Figure 1, the challenge device networking product designers face is how to make the burgeoning array of RS-232/485 or increasingly USB devices accessible over the house network while providing the rich networking features used by the PCs also connected to that network.

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Figure 1 (click to zoom)

It’s important not to forget that device networking product manufacturers find themselves in a highly competitive marketplace where design is semi-bespoke and the need for differentiation is high, yet also where cost is highly sensitive and time to market is of paramount importance. There’s no doubt that the aspect of connectivity is a crucial one. But in itself, connectivity adds little value – it just needs to be there and work. The true product differentiation is best related to the features and capabilities of the software running on the product.

Getting the network to the device
In many applications, device networking has traditionally relied on a PC and the use of PCI add-in cards. The disadvantages are obvious: it’s a large, expensive box (particularly if it’s an industrially hardened breed) and it consumes a large amount of power. On the upside, it offers a feature-rich OS, takes care of networking and connectivity aspects, and allows custom applications to be added easily.

A more recent trend in many sectors has been to do away with PC-oriented solutions and replace them with dedicated device networking products that save on both space and power, which handle all the connectivity and provide product designers with the flexibility to add their own unique value to a given application. However, for many organizations, this move can be an onerous one.

Consider the step of basing a new device networking product’s design around an off-the-shelf microprocessor and separate connectivity chips (Ethernet, USB, serial, and so forth). At face value, the solution presents a clear advantage in that designers can choose exactly what they want with the right cost/feature mix. But each component must be separately identified, validated, and integrated with the rest of the system – steps that would undoubtedly require some additional glue logic, probably in the form of an FPGA.

Once through the component selection process, however, the real challenges begin. Considering the networking capabilities needed, an OS must be selected, purchased, and then integrated with the microprocessor, toolchain, and the design environment. The selected OS might have device drivers for the chosen connectivity chips, but if not, designers will need to write and integrate them, a task that can be both difficult and time consuming.

And when it comes to more sophisticated networking, there’s even more complexity to deal with. In reality, networks assume that all devices on the network have the capabilities of a PC and can support such things as SSL, SSH, DHCP, Web servers, and so on. Again, if the OS doesn’t support these features, designers will need to write them or, in a worst-case situation, change the OS.

Future proofing a design in this environment is problematic, as customers invariably request features that were never considered in the original design. Having the flexibility to extend the product’s capabilities, both from a hardware and software point of view, is then essential for capitalizing on business opportunities. Processor and OS selection are therefore critical.

Particularly to an organization that’s more rooted in hardware rather than software design, this can be a real issue. The whole aspect of network connectivity may lie way outside of many designers’ comfort zones and involve making difficult software and hardware selection decisions that could later limit the product’s commercial potential.

A simpler SoC platform
To address these design issues, Oxford Semiconductor has developed the concept of a network connectivity platform. In summary, this SoC-based solution aims to offer device networking product designers the following ingredients:

• A powerful compute engine
• A feature-rich OS
• A high-performance connectivity set
• Product customization – flexibility through both hardware and software
• Fast development – a fully integrated hardware and software environment

The whole idea of the OXETHU954, the company’s first network connectivity platform, is driven from the connectivity side. The SoC embeds many industry-standard connectivity ports (Ethernet, USB, serial, and PCI) and integrates them with an onboard ARM 926 microprocessor delivering 220 MIPS and requisite memory resources. The silicon, which comes preconfigured with an OS and software, is backed by Eclipse-based integrated development environment tools to enable easy application development.

The chip’s connectivity options are tailored as closely as possible to the needs of the target applications: factory automation, POS, and building management. In such applications, particularly in industrial arenas, serial communication remains important for device interfacing. The chip offers four high-speed UARTs to respond to RS-232/422/485 needs at transmission rates up to 1 Mbaud. In addition, two USB 2.0 full-speed host controllers and respective PHYs capable of operating at up to 12 Mbps are also included. As previously stated, the devices in these applications are relatively dumb and produce small amounts of data. Thus, more sophisticated interfaces are not required to bring them together. Figure 2 shows the chip’s architecture.

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Figure 2 (click to zoom)

On the networking side, the SoC integrates a 10/100 Ethernet MAC for wired network connections. Wireless network connections are also made in the shape of a PCI interface. As the standard expansion bus for the PC, PCI is supported by many peripheral chips covering serial, USB, FireWire, Ethernet, and IEEE 802.11 communication. As such, a PCI interface provides the flexibility to easily add more capabilities and functionality to a new product design.

A particularly topical economic argument supports the PCI option, too. Compared to consumer applications, many target device networking applications can yield relatively low-volume product runs, which can be unattractive to IEEE 802.11 chip manufacturers. Wireless Mini PCI modules, however, are available in any volume from a number of manufacturers and provide a solution without real commercial constraints, one that is readily interfaced to the connectivity platform via PCI.

Software powers the solution
And what about integrating all this connectivity in software? It’s here that the concept of the dedicated connectivity platform provides users with real value. Figure 3 illustrates the complete software development environment.

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Figure 3 (click to zoom)

Linux is becoming increasingly popular for embedded applications. Its advantage lies in the sophistication it offers, particularly in terms of networking and device driver support while having the flexibility to easily add functionality, good tool support, and no royalties. Being open source, it also enables users to leverage code developed by the community to save valuable engineering time. A commercial Real-Time Operating System (RTOS), on the other hand, is a closed environment, is typically limited in its features and functionality, requires a proprietary toolchain, and is not free.

Preconfigured with the Linux OS, the SoC assures users of a rich set of capabilities and transparent access to embedded communication stacks and a Board Support Package (BSP). Not simply providing the code that glues OS and hardware, the BSP also contains device drivers for all the onboard peripherals as well as some external ones (PCI to octal UART and 802.11, for example). Coupling Linux with PCI and the 220 MIPS offered by the ARM 926 provides product designers with tremendous flexibility to extend and modify their products to meet new commercial opportunities.

In this instance, the Wind River Linux platform is then an integral component in Oxford’s SoC solution, selected for its reliability. One of the industry’s leading commercial grade, develop-and-run solutions, the platform is based on a stable, tested, and validated Linux kernel and includes integrated patches and packages for advanced networking, security, and Carrier Grade functionality.

For application development, the SoC’s software development kit comes complete with a development board (shown in Figure 4) and a choice of development tools: Wind River Workbench and Code Sourcery G++. To save setup time, the Linux Root File System is already integrated. The tools provide an Eclipse-based development environment, but users have the option to work from the command line if they prefer.

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Figure 4 (click to zoom)

Saving time and effort
Integrating an OS and BSP with a dedicated connectivity platform can save time and effort in selecting and integrating the components that make up a device networking product. In short, this means designers don’t need to worry about any aspect of the connectivity. It does leave the application development itself, but that is exactly where the designer’s focus is best kept, as it is the application that adds the most value of all.

Adrian Braine is marketing manager for connectivity solutions at Oxford Semiconductor, where he is responsible for the company's range of serial communication, USB, and network connectivity products. He has been involved in electronic product design since 1984 and entered the semiconductor industry in 2000. During his years of experience, he has held director-level and senior engineering and management positions. Adrian has a BS in Electronic Engineering from the University of Brighton and the Chartered Institute of Marketing’s Professional Diploma in Marketing.

For more information, contact Adrian at:

Oxford Semiconductor
25 Milton Park
Abingdon, OX14 4SH
United Kingdom
+44 (0)1235 824 900
contact@oxsemi.com
www.oxsemi.com