Applications ranging from multimedia distribution to power and motor controlare looking to digital signal processors (DSPs)and digital signal controllers (DSCs) for optimal solutions now more than ever. The high end now trends toward multiple cores, while the low end sports microcontroller peripheral sets. DSP farms continue to escalate in size and power, and standalone chips complete with network protocol stacks tackle CPU chores.
DSPs Turning Microcontroller
Standard microcontroller peripherals like analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and serial and parallel ports have adorned DSPs and DSCs for years. Now, interfaces such as Ethernet and the Universal Serial Bus (USB) are normal fare. Other high-speed interfaces like PCI Express and Serial ATA have yet to make an impact, though highend DSPs offer communication links such as Serial RapidIO (sRIO).
As DSCs become more like general CPU architectures, they're adding more operating-system and protocol stack support. Therefore, a single chip can handle signal processing chores, as well as communication and peripheral interfaces for user controls. This makes for rather massive kits, like the Multimedia Kit around Analog Devices' Blackfin chip (Fig. 1). The board handles camera input, as well as audio and video I/O plus Ethernet.
Such varied support is critical with the rise of networking in the consumer space. HDTV, iPods, and streaming audio within the home all demand DSCs and DSPs. Meanwhile, DSPs—the driving force behind cell phones—are poised to be the underpinnings for Voice over IP (VoIP). The same is true for MP3 players and the latest wave of video players.
Look for more product lines to pare down as well, providing lower-end solutions with DSP-style power. Texas Instruments developed a DaVinci chip that forgoes its dual-core roots with a single-core DSP chip. Microchip also offers a pin-compatible CPU line that matches its dsPIC DSC. The CPU retains much of the DSC support. Lower power and lower cost are typical driving factors.
Lots Of DSPs
Cost often isn't a factor, which is just the opposite for performance and power. Applications such as HDTV and streaming video chew up DSPs as fast as they can be manufactured. Multiple DSPs on a board or module are quite common, and the need is expanding. Solutions like Surf Communications' SurfRider promise growth and flexibility (Fig. 2). Each DSP features a high-speed 1-Gbit Ethernet link that simplifies interfacing to the communication fabric.
Other high-speed serial interfaces (i.e., sRIO and Analog Devices' TigerSHARC link ports) address not only throughput but also pinout issues in reaction to the growing number of interface pins. Interface pins are becoming a significant concern, making high-speed links with their lower pin count critical to meeting the performance demands of developers.
The flip side of the cell-phone rage is the corresponding demand for basestation support, especially as the move to 3G and Wi-Fi quickens. Multicore solutions appear to be a way to tackle the performance issue.
DSC and DSP growth has a plus side for developers. Falling costs and rising performance are making solutions based on these platforms more economical. They also will open up new areas such as low-end motor control, where it was once impractical or uneconomical to utilize processor control.