Leveraging Processor Code for Modern Connectivity

This post sponsored by Texas Instruments.

Choosing processors can be a difficult task. There are so many good processors, but there is also a great deal of hype to sift through. It can be difficult to wade through the gristle and find the real meat. Even advertisements and specifications take liberties in suggesting that their part is the greatest thing since sliced bread. With all that spin, there’s a very real chance that—albeit well-advertised—a part just may not be ideal for the design at hand.

Once a new processor is chosen, the architecture is learned, the tools are gathered, the learning curve begins and designs are cranked out. Slowly at first, then with more rapidity and confidence as the subtleties of the architecture reveal themselves and code becomes more manageable.

But then comes the next project and the decision must be made again to choose the best processor for the job, or call into action the accumulated knowledge, tools and skill sets that comes with using the existing processors. This is not all that simple of a task, however, especially when it comes to implementing peripherals or functions not native to the original processor.

For example, the last task may not have needed DSP functionality, but the new one may. Similarly, the last design may have used a UART for communications, but the next uses a USB. It becomes more complicated when all of the specialty code is already written and debugged for the former processor.

How many engineers have time to pound that square peg into a round hole? Sure, with enough resources, time and code, you can implement your own USB functionality in software (and a little external hardware). CPLDs and FPGAs can match up with the processor to do the accelerated functions like DSP and offload the processor.

But, if you could choose a processor part that has the hardware functionality already built in and software stacks that are free to use, it becomes a win-win situation. What’s more, it would be ideal if your choice processor was a member of a well-established and supported family of processors—all code-compatible, scalable and available with a variety of mixed-and-matched peripheral and memory resources to grow. Nowhere is this more important than with communications protocols.

Communications protocols seem to gravitate toward industry segments. The previous example used UART and USB, but truthfully, different industries and applications demand different types of communications links and software stacks. For example, automotive designs may use CAN or even Ethernet, and factory automation may use Ethernet or PROFIBUS. What’s more, wireless links are now becoming low enough in cost to replace wired links—simplifying installation, maintenance and repair of deployed facilities.

Welcome to the Family

While smaller specialty semiconductor makers may have a secret sauce that excels in a very specific market, broad line and experienced manufacturers such as Texas Instruments have the most comprehensive umbrella offerings and support when it comes to implementing complex present-day standards and protocols. Processor families like the Sitara™ are based on the well-accepted ARM Cortex processor architecture that has proven itself for high-speed and low-power designs. The high-end Cortex A8 and A9 parts like the AM3357, for example, run up to 1 GHz with up to 2,000 MIPS and include on-chip L1 and L2 cache, plenty of RAM and flash, USB and a 2-port 10/100/1000 Ethernet switch.

Scaled-up Sitara family members like the ARM 9-based AM4377 add DSP extensions and functionality to handle everything from factory and industrial automation, to personal handheld or wearable electronics. In addition to the 2-port Ethernet switch, it features two channels of CAN and six UARTs as well as multiple IIC and SPI ports and other peripherals.

Tools of the Trade

When learning or implementing a new or established technology, the tools and support matter. With the Sitara, reference designs, development and test systems, source code and application support all converge to make development as straightforward and simple as possible.

Take for instance the TIDEP0001 board and reference design that features EtherCAT connectivity solutions. Schematics, test data, design files and complete BOMs are all free, as is stack code like the EtherCAT slave stack code.

Figure 1: A well-designed development board allows the same hardware and architecture to be used to swap out different code blocks, letting designers more rapidly develop and test communications protocols as needed. (Source: Texas Instruments)

The similar TIDEP0002 version uses the same TMDSICE3359 board, but focuses on industrial control and automation communications centered on PROFIBUS and Profinet. The pre-tested protocol stack has been certified by Siemens and allows the Sitara processors to tackle PLC, HMI and I/O solutions for industrial needs.

For Ethernet, IP and EtherCAT designs, the production-ready TIDEP0003 again uses the same reference design, coupled with on-chip two-port 10/100/1000 Ethernet hardware to provide out-of-the-box, cut-and-paste design implementation and testing, and multiple units can operate together thanks to a binary-coded Ethernet slave address switch.

It is important to note that major suppliers such as Texas Instruments are also in a better position to provide new and emerging design and development solutions for newer technologies as well. Take the Serial Real-Time Communications System (SERCOS) for noise-immune high-speed serial communications-over-fiber-optic media. Designed as an open-standard industrial communications protocol and covered by IEC 61491 specifications, the TIDEP0010 reference design and development kit includes the industrial-control engine coupled with conformance-tested firmware and register interface.

Data links in and out of designs may vary, but the core architecture can remain code-compatible. As new requirements emerge, there exists the possibility for the reuse of older algorithms and routines. Only the new communications links need to update, and with certified and tested code to plug in, this task is now much simpler.

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