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PIC33 FFT Exerciser Application

A FFT Exceriser using the PIC33 DSP and the16 bit Micro Experimenter

The PIC33F J128GP802 is pin to pin compatible with the PIC24F part that comes with the 16 Bit Micro Experimenter Kit, however, there are some significant differences. The PIC33F is has Digital Signal processing hardware , supports up to 128K Flash and can run up to 40 MIPS. It supports all the peripherals the the PIC24F supports in addition to a 12 bit ADC, DCI interface and built-in DMA.

We are introducing this part into the Experimenter to provide a new series of Digital Signal processing (DSP) applications, in this case doing a real time Fast Fourier Transform or FFT. The FFT is used to determine frequency spectrum content of a signal. Our FFT Exceriser does provides 32 point of real data from a 64 point FFT . The FFT is performed on a internally generated sine wave. This sine wave is sampled at 640 Hz internally resulting in 32 point spectra display where each frequency bin is equivalent to 10 Hz. The sine wave is viewable on the Graphic display ( for details on this hardware see Graphics). The output Spectrum results for the FFT are also visible. The application continually performs the FFT so that the user can instantly see the results on the graphic display as he or she changes the frequency manually. The frequency of the sine wave can be changed by the user with the Rotary Encoder ( for details on this hardware see rotary) .

For this application You need to remove the existing PIC24F part ( it is socketed ) and replace it with the PIC33F. The PIC33F J128GP802 part is available from Mouser as well as lots of other suppliers.

See photos. You will need to also install a free version of Microchip’s DSP DSC to compile the demo soft