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LPC2148 Baud rate mysteriously changed

LPC2148 Baud rate mysteriously changed

2006-03-02 by stephan2148

Hi, 
I had an application running a uart at 155200 on LPC2148, debugging as
normal with Jlink. Then I find the link quit, and I tracked it down to
the Uart now running at 9600 even though I tell it to run at 155200.
Setting the other end to 9600, the application works again, but I
don't want that baud.
Has anyone else run into this? I have a feeling it is the PLL messing
up. I had similar problems long ago, where I had nonstandard bauds
coming out and had to erase the part with the Philips utility.  I'll
try that to see if I get it back, but what happened?  Will it happen
again?
Thanks,
Steve

Re: LPC2148 Baud rate mysteriously changed

2006-03-02 by stephan2148

--- In lpc2000@yahoogroups.com, "stephan2148" <stephan2148@...> wrote:
>
> Hi, 
> I had an application running a uart at 155200 on LPC2148, debugging as
> normal with Jlink. Then I find the link quit, and I tracked it down to
> the Uart now running at 9600 even though I tell it to run at 155200.
> Setting the other end to 9600, the application works again, but I
> don't want that baud.
> Has anyone else run into this? I have a feeling it is the PLL messing
> up. I had similar problems long ago, where I had nonstandard bauds
> coming out and had to erase the part with the Philips utility.  I'll
> try that to see if I get it back, but what happened?  Will it happen
> again?
> Thanks,
> Steve
>
Make that "115200".  And, I also notice that my other Uart that is
used at 9600Baud, IS at 9600 baud still working.  So, now they are
both at 9600 while I wanted one at 9600 and one at 115200.?

Re: [lpc2000] Re: LPC2148 Baud rate mysteriously changed

2006-03-02 by Bertrik Sikken

stephan2148 wrote:
> --- In lpc2000@yahoogroups.com, "stephan2148" <stephan2148@...> wrote:
>>
>> Hi,
>> I had an application running a uart at 155200 on LPC2148, debugging as
>> normal with Jlink. Then I find the link quit, and I tracked it down to
>> the Uart now running at 9600 even though I tell it to run at 155200.
>> Setting the other end to 9600, the application works again, but I
>> don't want that baud.
>> Has anyone else run into this? I have a feeling it is the PLL messing
>> up. I had similar problems long ago, where I had nonstandard bauds
>> coming out and had to erase the part with the Philips utility.  I'll
>> try that to see if I get it back, but what happened?  Will it happen
>> again?
>> Thanks,
>> Steve
>>
> Make that "115200".  And, I also notice that my other Uart that is
> used at 9600Baud, IS at 9600 baud still working.  So, now they are
> both at 9600 while I wanted one at 9600 and one at 115200.?

So your baud dropped by a factor of 12. Is there a factor 12 somewhere
in your PLL configuration? Like dropping from 3 x Fcrystal with VPB
divider set to 1 to 1 x Fcrystal to VPB divider of 1/4th?

If erasing the part helps, then I can imagine that there is still
some code in flash that sets the baud to 9600 and you accidentally
jumped into it.

Regards,
Bertrik

Re: LPC2148 Baud rate mysteriously changed

2006-03-02 by stephan2148

--- In lpc2000@yahoogroups.com, Bertrik Sikken <bertrik@...> wrote:
>
> stephan2148 wrote:
> > --- In lpc2000@yahoogroups.com, "stephan2148" <stephan2148@> wrote:
> >>
> >> Hi,
> >> I had an application running a uart at 155200 on LPC2148,
debugging as
> >> normal with Jlink. Then I find the link quit, and I tracked it
down to
> >> the Uart now running at 9600 even though I tell it to run at 155200.
> >> Setting the other end to 9600, the application works again, but I
> >> don't want that baud.
> >> Has anyone else run into this? I have a feeling it is the PLL messing
> >> up. I had similar problems long ago, where I had nonstandard bauds
> >> coming out and had to erase the part with the Philips utility.  I'll
> >> try that to see if I get it back, but what happened?  Will it happen
> >> again?
> >> Thanks,
> >> Steve
> >>
> > Make that "115200".  And, I also notice that my other Uart that is
> > used at 9600Baud, IS at 9600 baud still working.  So, now they are
> > both at 9600 while I wanted one at 9600 and one at 115200.?
> 
> So your baud dropped by a factor of 12. Is there a factor 12 somewhere
> in your PLL configuration? Like dropping from 3 x Fcrystal with VPB
> divider set to 1 to 1 x Fcrystal to VPB divider of 1/4th?
> 
> If erasing the part helps, then I can imagine that there is still
> some code in flash that sets the baud to 9600 and you accidentally
> jumped into it.
> 
> Regards,
> Bertrik
>
I believe that is what happened.  In testing, I swapped the Uarts and
bauds at one point.  I think it was overriding my debug code somehow..
It is now working again at 115200. Thanks

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