C design goes 'soft'

A demonstration at the recent Embedded Systems Conference suggests that C-language hardware design may in fact be practical. What's more, it showed that an emerging approach to electronic design-one that uses reconfigurable logic with a standard processor-could become a viable alternative to ASICs.

The demo was held by Proceler, an embedded-systems startup that announced its mission several weeks previously (see March 26, page 95). Proceler's Dynamically Variable Instruction Set Architecture, or Dvaita, lets designers write C-language programs that are compiled into application-specific "soft processors."

What Proceler promises is a compiler that can automatically take C code and select computationally intensive portions. That code is compiled into reconfigurable logic using Proceler's customized "soft" instruction-set architecture. It creates units of logic that have their own state machines and storage registers and are crafted for a high degree of acceleration. Meanwhile, the noncomputationally intensive code is compiled into a C-language program for the standard processor.

A user can thus quickly create a custom system-on-chip without designing any custom hardware. There's no synthesis or placement and routing-it all takes place under the hood, with Proceler's tool and with FPGA vendor back-end tools. And to change functionality or move to different hardware, you just recompile. It's hard to beat for time-to-market and flexibility.

Krishna Palem, Proceler CTO, acknowledged that this approach won't provide ASIC-level performance. But he said there are many application areas, such as networking and industrial automation, where it makes sense. There's a spectrum between standard processors and ASICs, Palem said, and Proceler's approach is somewhere in the middle.

At the demo, Proceler compiled C code onto a board-level system that included a Xilinx FPGA and a PowerPC processor. (The product's first release this fall will support an integrated Xilinx device with a PowerPC.) Proceler is also talking to Altera and Triscend and says it intends to remain vendor-neutral.

The Proceler approach sounds a lot like Synopsys' Nimble Compiler project, but Proceler is not tied to a custom architecture and requires no synthesis, Palem said.

Some observers think that C-language design with programmable logic will replace custom hardware. I don't think ASICs will go away, but I do think there's an alternative that will make sense for some types of applications.