This month, Microchip Technology announced the dsPIC33F family of 16-bit, flash-based “digital signal controllers,” or “DSCs.” (The term “DSC” refers to microcontrollers that include support for digital signal processing.) The 3.3-volt dsPIC33F uses the same instruction set as its predecessor, the dsPIC30, but the new family will run at a faster clock speed (40 MHz vs. 30 MHz) and add an 8-channel DMA controller.
The dsPIC33F family will include 27 members that target a variety of low-cost, microcontroller-oriented applications such as answering machines, two-way radios, and washing machines. Fifteen of the chips are intended as general-purpose chips, and include one or two 12-bit A/D converters and a codec interface. The other twelve are tailored for motor control and power conversion applications, and include one or two 10-bit A/D converters, pulse width modulation, and a quadrature encoding interface. All chips include flash memory and are expected to operate at 40 MHz. “Early adopter” samples are available now; generalized sampling will begin in the first quarter of 2006. Pricing will range from $5.43 to $10.31.
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.
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