Lpc2000

Another question.  If the LPC is being driven by an oscillator,
has the output of the osc been divided down and capacitively
coupled to the LPC?  Direct drive from an external osc will
allow the LPC to 'almost' work but because the waveform is
distorted, the problem will show up when trying to download
to flash.

-Bill Knight
the ARM Patch




On Fri, 07 May 2004 08:53:17 -0400, Robert Adsett wrote:

At 07:30 AM 5/7/04 +0000, you wrote:
>--- In lpc2000@yahoogroups.com, "James Dabbs" <jdabbs@t...> wrote:
> > We're attempting to program our target board using the Phillips ISP
> > utility.  We've used both the "Phillips LPC2000 Flash Utility
>V2.1.0"
> > and an earlier version of it, on 2 PC's -- a desktop and a laptop,
>both
> > running Windows 2000 and using "normal" non-USB serial ports at 9600
> > baud.
> >
> > I can manually go in with HyperTerminal, get synchronized, and issue
> > commands to read the device ID.  This works great.  But with the
>Flash
> > Utility, I click the "Read Device ID" button  on the main form,
>push the
> > reset button when the "Please Reset your LPC2000 board now and then
> > press OK!" dialogue asks me to, and then I click OK.  The utility
>comes
> > back instantly and says, "Cannot communicate with test board!"
> >
> > This app uses the secondary JTAG port, so we've got to figure this
>out.

>Have you set the crystal frequency? It's on the left of the window
>and quite easy to miss.

I can see how that might cause an error, just not the one he's seeing.

I'd suspect that the baud rate was marginal for the crystal but 9600 baud 
seems low enough that there shouldn't be a problem. That leaves marginal 
oscillator or connections and either he's seeing a sampling effect in the 
error preference or there's some non-obvious difference in the way the two 
are being done.  (or maybe he's trying to steal power off of the serial 
handshaking lines).

James, not much help, more of a verification step.  Have you tried 
performing an experiment where you do 10 or so of each method (manual sync 
and read device id) and recording the results?

Also, does this happen on multiple boards?  It sounds like this might be 
the first board you are bring up?

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III





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