Lpc2000

Hi Charles,

Thanks for the suggestions - all relivant details.... However some 
cores do radiate abormally higher than others.

Using an RF probe and a spectrum analyser over the package you
CAN see the difference in radiation levels of noisy cores.

Yes - there are methods to "sheild" noisy cores - but - why start 
with one in the 1st place.

Philips did an app note 10~15years ago discussing the advantages of
LQFP over DIP in relation to RF EMC radiaion characteristics.

Regards
Joseph

--- In lpc2000@yahoogroups.com, "charlesgrenz" <charles.grenz@s...> 
wrote:
> 
> Hello,
> 
>   I am currently in the middle of a design for the 2138. EMI is 
very
> important in the design. 
> 
>    Are you used multilayer boards? How about series resistors on 
all
> the lines (both input and output)? Do you have a resistor in series
> with the XTAL2 output? How about 100pF capacitors on all the I/O 
that
> goes off the board. What crystal frequency are you using? How about
> ferrites on all level transistion devices (like RS232 and such)?
> 
> Thanks
> Charles
> 
> 
> --- In lpc2000@yahoogroups.com, "tsvetanusunov" <tusunov@m...> 
wrote:
> > 
> > > Some micro's have terible radiation characteristics and are 
> > > unsuitable to in radio modems with sensitive analogue 
frontends.
> > > 
> > > ARM controllers are used in mobile phones  etc.
> > > 
> > > What characteristics do the LPC2000 have that lend thenselves
> > > radio modems / phones etc.
> > 
> > this is very interesting topic, I can't find any info on this in 
LPC 
> > datasheets, but we found interesting feature: when LPC PLL is 
enabled 
> > if you have near by (1-2 meters) FM radio you can hear the sweep 
tone 
> > for about second.
> > Our QC found this as they have radio on their desk where LPC 
boards 
> > are tested, no one of other microcontrollers we used make such 
> > interference to the radio.
> > 
> > Best regards
> > Tsvetan
> > ---
> > PCB prototypes for $26 at http://run.to/pcb 
> > (http://www.olimex.com/pcb)
> > PCB any volume assembly (http://www.olimex.com/pcb/protoa.html)
> > Development boards for ARM, AVR, PIC, and MSP430  
> > (http://www.olimex.com/dev)