In DSCs, speed isn’t the hot metric that it
is for other signal processing chips. Assuming the chip is fast enough
for the modest processing requirements of the target application,
designers are far more interested in price, and in whether there is
relevant on-chip integration. In these respects, the 40 MHz dsPIC33F is
in a good position, offering a wide variety of price points and a range
of different peripherals. Based on BDTI’s benchmark results, the 40 MHz
dsPIC33F will have a BDTIsimMark2000 score of 130, which is on the low
end of the range of scores for DSCs—but should be sufficient for many
less-demanding applications. The dsPIC33F will see some strong
competition, however, from Freescale’s flash-based 60 MHz 56F8xxx. This
chip family targets similar markets, is similarly priced, and is
noticeably faster—its BDTImark2000 score is 170.
Other competitors include TI’s 16-bit ‘C24x and 32-bit ‘C28x families,
and ADI’s 16-bit ‘2199x family. The older, 40 MHz ‘C24x family is
roughly comparable to the dsPIC33F in terms of speed and price. Both
the ‘C28x (which runs at 100 or 150 MHz) and the ‘2199x (which runs at
160 MHz) are significantly faster than the dsPIC33F—but both are also
more expensive.
The good news for system designers is that there are now many
attractive choices in DSCs, and the range of offerings is expanding at
a healthy clip. In the last few months we’ve seen new chips in this
space from both Microchip and Freescale, and a new DSC core, the ZSPneo,
from LSI Logic. We expect to see additional activity in this area as
products that use motor control continue to expand their signal
processing capabilities.