How can I get started learning how to program dsPICs in C?

I am familiar with programming 8-bit PIC microcontrollers in assembler and C, and am interested in learning how to build simple DSP projects using the dsPIC line of microcontrollers. I can handle the hardware end and the mechanics of programming using MPLAB etc; I'm looking for a good primer on how to get started using these chips in C/C++ (assembler looks to be less efficient here, from reading the datasheet.) I'm working with a dsPIC30F4013, but am mostly interested in the general way of working with them.





For instance, how would I use the dsPIC to go about designing a DSP single-pole low-pass Butterworth filter with a cutoff of 1kHz?





Alternatively, if you don't recommend using the dsPIC, I'm open to other suggestions as long as the parts are:


* DIP form factor or similar,


* relatively inexpensive, and


* fairly easily programmed.





(I know this is a large, complex topic; I'm mostly looking for a book or website recommendation to help me get started.)





Thanks in advance.

How can I get started learning how to program dsPICs in C?
I'll just make one recommendation:





In a limited program space (which you have), while C may be more efficient in terms of amount of code function produced per unit time, assembly is far more efficient in code space use. Most serious embedded programming for limited code space is done on the bare metal for a reason.