The power of a customizable digital signal processor (cDSP) chip from TI has allowed San Jose's Maxtor Corp. to deliver the industry's first hard disk drive (HDD) whose sole processing element is a DSP.
Maxtor is the first HDD manufacturer to adopt a uniprocessor DSP design, combining DSP and microcontroller functions onto a single high-performance, customizable DSP-based processing unit, eliminating the need for a microcontroller chip. Superior code-execution speeds on the TI part enabled a cost-effective increase in HDD track density on Maxtor's PCMCIA-format MobileMax™ 171, and efficient DSP software development tools resulted in faster time-to-market than with previous HDD designs.
In addition to a microcontroller, many dual-processor HDD architectures often use a DSP for servo-control, enabling higher track densities through sophisticated control algorithms. An inherent RISC architecture allows a DSP to execute servo-control code more than ten times faster than a typical microcontroller. Continued price reduction pressure and physically smaller disk drives preclude the dual use of a microcontroller together with a DSP, requiring a uniprocessor design approach.
TI's T320C2xLP is a source-code compatible replacement core for the widely used TMS320C25 DSP. The 28.5-MIPS, 16-bit processor core is coupled with 1 KByte of RAM, an IEEE 1149.1 emulation and test bus controller, and 10,000 gates of ASIC logic. For the MobileMax 171 project, the 'C2xLP ASIC logic is used to implement servo timing and control and power management functions. DSP software is used to replace classic hardware functions like real-time error correction, predictive caching, and adaptive disk-head equalization.
"Not only did the 'C2xLP programmable DSP core provide enough computing power for a uniprocessor DSP solution," said Alex Gorjanc, TI's HDD strategy manager, "but the device's customizable integrated logic and the replacement of some hardware functions with software dramatically cut Maxtor's parts-count and product cost." The use of the TI part helped Maxtor cut the cost of MobileMax 171 drive electronics by about 30 percent over previous similar designs.
The DSP solution provided by the T320C2xLP offers long-term benefits to Maxtor through highly-flexible programmability and a TI device-technology roadmap which promises wholly compatible versions of the chip. By incorporating an increasing number of functions in software, Maxtor has ensured that future designs can quickly and easily take advantage of new TI DSP technology to continue to drive the dollars-per-megabyte HDD metric down.
Contact TI regarding a T320C2xLP core-based customizable DSP.