LSI Logic recently added two new processors, the ZSP200 and the ZSP540, to its ZSP family of superscalar DSP cores. With the addition of these cores, the ZSP family has become the largest family of code-compatible DSP cores available today. As with existing family members—the ZSP400, ZSP500, and ZSP600—the names of the new cores reflect their levels of parallelism. The ZSP200 offers less parallelism than the ZSP400, while the ZSP540 falls between the ZSP500 and ZSP600 in terms of parallelism.
In some ways, the ZSP200 resembles a ZSP400 cut in half. For example, the ZSP400 contains two multiply-accumulate (MAC) units, while the ZSP200 offers one MAC unit. However, the ZSP200 retains both of the ALUs found in the ZSP400. The ZSP200 also adds hardware loop support that is missing in the ZSP400. These features will likely make the ZSP200 faster than might be expected for a single-MAC version of the ZSP400.
The ZSP200 targets low-cost, low-power signal-processing applications. Based on BDTI's analysis of the older ZSP400, the ZSP200 is likely to be highly competitive in these applications. Memory use is a major contributor to system cost, and the ZSP400 is one of the most memory-efficient processors BDTI has benchmarked. The ZSP400 is also one of the most energy-efficient cores BDTI has benchmarked. It will be interesting to see if the ZSP200 can surpass the high marks set by the ZSP400.
As its name suggests, the ZSP540 is similar to the ZSP500. The main differences between the cores are that the ZSP540 doubles the number of MAC units from two to four and doubles the data memory bandwidth from 64 bits to 128 bits per cycle. The ZSP540 also adds hardware loop support not found in the older cores. These features will make the ZSP540 faster than the ZSP500 and possibly even faster than the ZSP600. This possibility casts doubt on the future of the ZSP600. It will be interesting to see how LSI Logic evolves the ZSP600 to address this apparent overlap in performance.
For more on the ZSP200, see “LSI Logic's DSP core targets high volume apps.” For an in-depth analysis of the older ZSP500, see BDTI's report Inside the LSI Logic ZSP500. Excerpts from the report are available online at www.bdti.com