The new chips were announced as part of TI's low-power roadmap. The devices span four product lines: C550x, C640x, C674x, and OMAP-L1x.

Table 1. TI's low-power families.

The C674x is TI's first low-power floating-point DSP. TI claims that the C674x is the industry's lowest power floating-point DSP. Compared to previous-generation TI DSPs, the C674x cuts active power by 3X and slashes standby power by 20X. The devices target a variety of audio, medical and industrial applications. For instance, a music effect pedal powered by the C674x could run all day at a music festival without recharging.

The C674x is also notable because its instruction set is a superset of the fixed-point C64x+ and floating-point C67x+ instruction sets. This is a major shift for TI; for years its fixed- and floating-point C6000 families evolved in separate directions, creating incompatibilities. The C674x fixes the problem. Fixed-point C64x+ object code will run on the new architecture without any porting. The C674x also introduces new 24-bit operations. These new operations are well-suited for audio applications, which commonly use 24-bit data.

The OMAP-L1x line also represents a number of changes for TI. All products in this line are pin-compatible, and all devices feature an ARM9 core. The ARM9 is optionally paired with a C64x+ core, C674x core, or audio coprocessor. The OMAP-L1x devices are also pin-compatible with devices in the new C674x and C640x product lines, giving designers a wide range of CPU options. This pin-compatibility gives TI an important competitive advantage. "It is a good move," says Jeff Bier, President of independent analysis firm BDTI. "I cannot say definitively that no one else is doing this, but no one else immediately comes to mind, at least not in this space."

The C640x DSPs are based around TI's C64x+ DSP core. According to TI, these devices consume half the power of existing C64x+ DSPs. They aim to add portability to processing-intensive applications such as software defined radio, industrial instrumentation, and emerging markets.

The C550x DSPs are intended for the most power-sensitive applications, including portable medical devices, noise reduction headphones, and portable audio/music recording devices. The C550x features a large on-chip memory as well as an FFT/FIR filter coprocessor—the first such coprocessor TI has offered. For applications requiring FFTs or FIR filters (which includes most DSP applications), this coprocessor provides a significant boost in performance and energy efficiency.

Table 2 compares TI's new devices to Analog Device's Blackfin and SHARC families. Comparing power numbers is tricky, and all numbers presented should be taken with a grain of salt. Here we use the metric of MMACs (millions of multiply accumulate operations per second) per mW. Among the low-speed fixed-point parts, Analog Devices has a modest lead, but TI's numbers are quite respectable. Note that the C550x numbers do not leverage the FFT/FIR coprocessor. For FFT/FIR intensive applications, the C550x will be much more efficient. Among the higher-speed devices, the TI C640x is the clear winner. For the floating-point processors, the C674x beats ADI's SHARC by roughly 3X.

Table 2. TI versus Analog Devices.

TI's dramatic new focus on power is impressive, but not surprising. The last few years have seen an escalating emphasis on power. Until recently performance was the biggest bottleneck in DSP systems; now, energy consumption dominates. Power is obviously important for portable devices, where battery life is a concern. It has also become a concern for line-powered products. These devices increasingly involve small form factors, limited power supplies, low noise (and thus no fans) and other factors that push designers to cut power. TI's announcement is likely to be only the first of many focusing on low power.

The new chips will begin sampling in Q4 2008 and will roll out throughout the next twelve months. Prices will vary, but start at less than $9 (100 units). For more details, see www.ti.com/lowpowerprocessorsee.

(Note: The original version of this story had incorrect C640x and Blackfin performance data.)