Dave Dilatush wrote:
> I set up a test with a PIC18F242 and a dsPIC30F3013, operating in
> various oscillator modes and frequencies.  Full results are in
> the attached text file,

Very interesting.  Thanks for doing this.  I notice that both PICs are
running well below their maximum specified current for the various
oscillator frequencies.  Your numbers are therefore a rough guide of what
you might get as apposed to something to design with.  Unfortunately I only
have an old 18Fxx2 data sheet here that has "advance infomation" written
accross all electrical specs, and I don't feel like waiting to download new
data sheets for the 18F242 and 30F3013.  My old 18F data sheet shows max
current draw at 40MHz as 38mA, and I sortof remember a dsPIC at 120MHz is
about 180mA(?).  If so, that's only 1.6x more current for the dsPIC after
adjusting for the clock speed ratio.

> but overall it looks like the
> dsPIC30F3013 can be expected to draw roughly two and a half to
> three times the operating current as a PIC18F242 operated at the
> same clock frequency.

For the single measured case.  I'm not trying to minimize what you did, but
it's important to note the your data is interesting and a useful guide, but
that there is no substitute for the specified maximum currents when
designing a circuit.  (I know you know this, but I want to make sure others
watching this look at it with the proper perspective.)

> This is my first dsPIC project, and my initial impression is that
> while the learning curve is big (not difficult, just a lot of
> work), so is the payback: these things are REALLY easy to work
> with.

I agree wholeheartedly.  I find the dsPICs easier to program than the 12,
16, or 18 PICs.


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