Octasic Semiconductor recently announced the OCT2200 family of multi-core DSP processors based on its Opus clockless (asynchronous) DSP core. The OCT2224M is intended for media processing equipment including video conferencing systems, internet video streaming and transcoding, and video surveillance. The OCT2224W is designed for wireless applications, notably smaller basestations such as femtocell, picocell, and low power basestations. According to Octasic, it can support GSM, EDGE, HSPA, WiMAX and LTE standards. Octasic, headquartered in Montreal, was founded in 1998 with an emphasis on voice digital signal processing.
The new devices include an ARM CPU and 24 Octasic Opus DSP cores. Previous Octasic products-Vocallo MGW for video and Vocallo BTS for wireless-had 15 DSP cores. Octasic states that its clockless architecture has performance equivalent to 1.2 - 1.5 GHz per DSP core, while using half the silicon area and one third the power of traditional synchronous DSP core designs. Octasic claims a 3X performance increase from its previous generation Vocallo products to the OCT2200 line, with 1.5X due to the higher number of cores, and 2X due to other architectural enhancements.
A notable feature of Octasic’s technology is its clockless architecture. Clockless architectures typically rely on a handshake mechanism whereby one stage of logic signals to the next that an operation has completed. Potential benefits include lower electromagnetic emissions, lower power consumption, and more reliable operation over a wider range of operating conditions. Clock signal distribution, which consumes 15-35% of the energy in a typical processor design, is eliminated in clockless architectures. Further, dynamic power consumption can be lower because data circuits dissipate power only while performing useful work. While many academic examples of clockless processors exist, they have not gained widespread commercial acceptance. Other notable commercial examples include Fulcrum Microsystems which focuses on networking applications, and the Handshake Solutions ARM996HS processor which focuses on automotive applications.
Little product information (including performance data) has been disclosed about the Octasic products, and therefore it is difficult to establish the validity of the company’s power, performance and die size claims. Semiconductor providers with unique architectures, such as Octasic, often compete by developing complete system-level solutions targeting specific markets where they believe their architecture holds promise. This helps to prove the benefits of their architecture and spur demand without requiring customers to work directly with an unfamiliar architecture. Octasic’s development of video transcoding cards and echo cancellation modules appears to reflect this strategy.
For customers willing to program a novel architecture, Octasic’s software development flow is built using Microsoft’s Visual Studio environment, and includes an optimizing C compiler and application profilers. Octasic expects developers to use the C compiler initially, then employ hand-written assembly code for critical code sections. Multiprocessing is achieved by manually partitioning the workload among multiple cores and using a multiservice kernel to communicate between cores.
According to Octasic, the media targeted product-OCT2224M-is capable of up to 800 channels of VoIP functionality, or can encode 2 H.264 1080p video streams in 3.5 watts, while the wireless product-OCT2224W-can support up to 64 HSPA+ or LTE users while running the LTE MAC and PHY layers. With this new wireless product, Octasic will compete against a growing field of silicon targeting basestation applications, including products from TI, Freescale, LSI logic and picoChip.
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