[sdiy] Speaking of dsPIC microcontrollers...

[Eric Brombaugh]

On 12/22/2010 09:51 AM, Paul Maddox wrote:

> It's interesting to see what devices people pick to use for their
> projects, it'd be nice to understand why they make their choices.

I've tried a lot of processors over the last few years - dsPIC, ARM7, 
ARM9, DSP56k, TMS320XXX, MIPS, etc. I'm still using dsPIC though. Reasons:

* Inexpensive ($5 - $10 in small qty)
* Wide variety of pinouts, packages to suit different types of development.
* Nice instruction set, lots of gen. purpose registers
* Lots of docs, libraries & examples
* Good peripherals (DMA, SPI, I2C, Codec ifc, DAC, etc)
* True DSP (MAC with dual parallel operand prefetch & address updates)
* Reasonably fast, single-cycle instructions, no wait states for RAM, 
Flash at full speed.
* Decent IDE, C compiler is free (with limitations)
* Inertia - I already know it.

There are a few things I don't like too:

* Power diss a bit high at max clock rates
* Documentation can be a bit cryptic
* 16-bit math limits some functions, double-precision slows things down.
* Limited on-chip RAM & no simple/fast external mem expansion
* No USB peripheral
* Max clock rates a bit low compared to some DSPs
* No up-to-date OSS/Free dev tools

Overall the upside outweighs the downside for me. I've done more than a 
dozen projects with this processor family and except for systems with 
extreme requirements I'm not likely to change in the near future.

Eric