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Early Software Development And The Supply Chain

Virtual prototypes are essential to effectively debugging a system and still meeting market windows.

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By Achim Nohl
In my last blogs I have been focusing on introducing the technical advantages of virtual prototypes in the context of debugging embedded software. In this blog I would like to introduce how this can impact an entire supply chain.

The increasing complexity of software in terms of code-size, functions and layers, along with multicore SoCs, also demands more capable debug solutions. Those debug solutions have to go beyond a single CPU and provide a holistic view of the entire system with all its signals and registers for internal and external communication. A virtual prototype can deliver on those requirements independent of the hardware design schedule. Early, more productive and predictable debugging provides real advantages to VP adopters today. But it becomes even more compelling when you extend these advantages to your own customer, or even the customer’s customer. In the context of a supply chain, the impact of this time advantage can be multiplied with each stakeholder.

For example, Altera recently announced availability of the “Industry’s First Virtual Target for Software Development on SoC FPGAs.” “Virtual Target” is the term used by Altera to describe the virtual prototype (VP) for its SoC FPGA. Altera has identified VP as an essential tool that enables its customers to bring up their software earlier, more efficiently and with less risk. This again enables their customers to be ready for the market faster, with better quality software.

However, what’s also important for successful VP adoption by software developers is the support of a standard software development ecosystem. Before being able to educate software developers and convince them of the value of new complementary, VP-enabled debugging methods, it is important to make sure the software developers can use the software tools they are familiar with. I have seen that users quickly realize how much more they can suddenly do with a VP. Often this requires just a few hours of sitting together and doing some hands-on exercises with the user’s software.

When VPs are used to virtualize FPGAs and enable software development for custom hardware extensions, a few more aspects should be considered. In essence, the extension of the VP with hardware such as accelerators or peripherals is important. Otherwise, the VP cannot be used for custom device-specific driver development. In this case, the extension is achieved through an FPGA-in-the-loop extension where the real FPGA is connected to the VP using a virtualized PCIe interface. The advantage of this approach is that RTL can be re-used by the customer. Peripherals can be tested with the real hardware PHYs and real I/O. Custom accelerators, for example video and wireless, can be tested with the final targeted performance in context of the software. Altera offers this extension with its new SoC FPGA in its recently announced Virtual Target.

Of course, Altera is not the first to make this connection between early software development and the supply chain’s needs. The mobile industry has been working on this for some time. As software complexity grows at even the lowest layers of the SW stack, such as the OS kernel, drivers and middleware, the benefit of early customer enablement becomes more and more important for SoC vendors.

For sure, the general concept of using simulation for supply chain enablement is not new. In the context of enabling application developers for mobile phones, simulator-based SDKs have a long history. A big success story for simulation-based SDKs is, of course, the iPhone SDK and Google Android SDK. The first phone, the HTC Dream, was released in October 2008. Currently there are 167 apps available. To a large extend this has been enabled through the Android SDK, which Google released as an “early look SDK” version in 2007. The Android SDK uses the popular Qemu emulator for ARM as a back end that simulates an ARM-based hand-set. This is similar to a VP, but in general is more generic as some HW is even functionally abstracted. Google has achieved two important goals with this:

  1. Google has educated a huge SW community on its product.
  2. Google got a significant amount of feedback from developers that are already familiar with the iPhone to improve Android for its 1.0 release in September 2008

Today mobile device manufacturers are continuously extending their software-based emulators to support their custom hardware and win new software developers for it. For example, Kyocera is providing add-ons to simulate its “Dual Screen” devices, LG offers support for “Real 3D” and Samsung enables SW developers for their “Galaxy” Tablet.

Again, a significant additional benefit is that customers can provide feedback much earlier about concept flaws or unmet requirements. And when using a VP this can happen early enough so that problems can still be fixed without going through silicon re-spin. While the mobile device industry seems an obvious case, it’s interesting to note that the FPGA industry’s complexity has advanced enough that Altera has invested in virtual prototyping. So, who’s next? Xilinx?

–Achim Nohl is a solutions architect at Synopsys.