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Discussion Groups | LPC900 | LPC908 System Clock Problem
Find help, specifications and source code for the LPC900. The LPC900 challenges Microchip and AVR based on the worlds most popular 8-bit architecture the 80C51. With a 2-clock core the LPC900 series is a high performance, very flexible and low cost 8-bit microcontroller family. Designers using or interested in these devices are encouraged to share their know-how and ask questions.
LPC908 System Clock Problem - mshadow65 - Sep 19 13:51:57 2006
Hi everyone!
I'm using a LPC908 chip and i found problems using
the internal RC oscillator.
On user manual i can read it is factory-trimmed to 7.372.800 Mhz
but, generating the baud rate using the internal BRG, the frequency
seems to be quite different, at least 1mhz less.
Obviously i dont use the TRIM register
Do anyone discovered a similar problem using the UART and BRG?
Furno Gianluca
------------------------------------------------------------
Furno G.Luca
MicroSHADOW Research (uS)
Development dept.
Via Garibaldi, 25
19020 Ceparana (SP) - ITALY
Tel : +39(0187)940951
Mobile : 3337665111
e-mail : i...@microshadow.com
web : www.microshadow.com
------------------------------------------------------------
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
Re: LPC908 System Clock Problem - zhongyongbofly - Sep 19 21:28:14 2006
change another chip to have a try again?
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(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
Re: LPC908 System Clock Problem - mshadow65 - Sep 20 9:13:45 2006
Change chip?
Of Course i have 25 pieces here. All seems to have the same
bahaviour! :|
Some tips from other LPC908 users?
Gianluca
--- In l...@yahoogroups.com, "zhongyongbofly"
>
> change another chip to have a try again?
>
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
Re: LPC908 System Clock Problem - Kevin - Sep 25 14:58:55 2006
Hi Furno,
I'm using a LPC903 and found the same problem, the formula for
calculating the values for BRGR0, BRGR1 says it should be 0x0030 for
an 115,200 baud rate but I had to set it to 0x0034 to make it work.
If you have access to an oscilloscope you could just adjust the
values until you get the right pulse width.
Kevin
--- In l...@yahoogroups.com, "mshadow65"
wrote:
> Hi everyone!
>
> I'm using a LPC908 chip and i found problems using
> the internal RC oscillator.
> On user manual i can read it is factory-trimmed to 7.372.800 Mhz
> but, generating the baud rate using the internal BRG, the frequency
> seems to be quite different, at least 1mhz less.
> Obviously i dont use the TRIM register
>
> Do anyone discovered a similar problem using the UART and BRG?
>
> Furno Gianluca
> ------------------------------------------------------------
> Furno G.Luca
> MicroSHADOW Research (uS)
> Development dept.
> Via Garibaldi, 25
> 19020 Ceparana (SP) - ITALY
> Tel : +39(0187)940951
> Mobile : 3337665111
> e-mail : info@...
> web : www.microshadow.com
> ------------------------------------------------------------
>
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
I'm using a LPC903 and found the same problem, the formula for
calculating the values for BRGR0, BRGR1 says it should be 0x0030 for
an 115,200 baud rate but I had to set it to 0x0034 to make it work.
If you have access to an oscilloscope you could just adjust the
values until you get the right pulse width.
Kevin
--- In l...@yahoogroups.com, "mshadow65"
wrote:
> Hi everyone!
>
> I'm using a LPC908 chip and i found problems using
> the internal RC oscillator.
> On user manual i can read it is factory-trimmed to 7.372.800 Mhz
> but, generating the baud rate using the internal BRG, the frequency
> seems to be quite different, at least 1mhz less.
> Obviously i dont use the TRIM register
>
> Do anyone discovered a similar problem using the UART and BRG?
>
> Furno Gianluca
> ------------------------------------------------------------
> Furno G.Luca
> MicroSHADOW Research (uS)
> Development dept.
> Via Garibaldi, 25
> 19020 Ceparana (SP) - ITALY
> Tel : +39(0187)940951
> Mobile : 3337665111
> e-mail : info@...
> web : www.microshadow.com
> ------------------------------------------------------------
>
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
Re: Re: LPC908 System Clock Problem - Jan Waclawek - Sep 26 3:41:11 2006
Actually, have you (Kevin or Furno) tried to read out the value of TRIM?
wek
Kevin wrote:
> Hi Furno,
>
> I'm using a LPC903 and found the same problem, the formula for
> calculating the values for BRGR0, BRGR1 says it should be 0x0030 for
> an 115,200 baud rate but I had to set it to 0x0034 to make it work.
>
> If you have access to an oscilloscope you could just adjust the
> values until you get the right pulse width.
>
> Kevin
>
> --- In l...@yahoogroups.com
>, "mshadow65"
> wrote:
> >
> >
> > Hi everyone!
> >
> > I'm using a LPC908 chip and i found problems using
> > the internal RC oscillator.
> > On user manual i can read it is factory-trimmed to 7.372.800 Mhz
> > but, generating the baud rate using the internal BRG, the frequency
> > seems to be quite different, at least 1mhz less.
> > Obviously i dont use the TRIM register
> >
> > Do anyone discovered a similar problem using the UART and BRG?
> >
> > Furno Gianluca
> > ----------------------------------------------------------
> > Furno G.Luca
> > MicroSHADOW Research (uS)
> > Development dept.
> > Via Garibaldi, 25
> > 19020 Ceparana (SP) - ITALY
> > Tel : +39(0187)940951
> > Mobile : 3337665111
> > e-mail : info@...
> > web : www.microshadow.com
> > ----------------------------------------------------------
______________________________
controlSUITE™ software. Comprehensive. Intuitive. Optimized.
Real-world software for real-time control. Details Here!
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
wek
Kevin wrote:
> Hi Furno,
>
> I'm using a LPC903 and found the same problem, the formula for
> calculating the values for BRGR0, BRGR1 says it should be 0x0030 for
> an 115,200 baud rate but I had to set it to 0x0034 to make it work.
>
> If you have access to an oscilloscope you could just adjust the
> values until you get the right pulse width.
>
> Kevin
>
> --- In l...@yahoogroups.com
>
> wrote:
> >
> >
> > Hi everyone!
> >
> > I'm using a LPC908 chip and i found problems using
> > the internal RC oscillator.
> > On user manual i can read it is factory-trimmed to 7.372.800 Mhz
> > but, generating the baud rate using the internal BRG, the frequency
> > seems to be quite different, at least 1mhz less.
> > Obviously i dont use the TRIM register
> >
> > Do anyone discovered a similar problem using the UART and BRG?
> >
> > Furno Gianluca
> > ----------------------------------------------------------
> > Furno G.Luca
> > MicroSHADOW Research (uS)
> > Development dept.
> > Via Garibaldi, 25
> > 19020 Ceparana (SP) - ITALY
> > Tel : +39(0187)940951
> > Mobile : 3337665111
> > e-mail : info@...
> > web : www.microshadow.com
> > ----------------------------------------------------------
______________________________
controlSUITE™ software. Comprehensive. Intuitive. Optimized.
Real-world software for real-time control. Details Here!
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
Re: LPC908 System Clock Problem - Kevin - Sep 26 21:40:07 2006
no, I haven't, I'm right in the middle of another project but I will
try it as soon as I can get back to it.
--- In l...@yahoogroups.com, Jan Waclawek wrote:
>
> Actually, have you (Kevin or Furno) tried to read out the value of
TRIM?
>
> wek
>
> Kevin wrote:
> >
> >
> > Hi Furno,
> >
> > I'm using a LPC903 and found the same problem, the formula for
> > calculating the values for BRGR0, BRGR1 says it should be 0x0030
for
> > an 115,200 baud rate but I had to set it to 0x0034 to make it
work.
> >
> > If you have access to an oscilloscope you could just adjust the
> > values until you get the right pulse width.
> >
> > Kevin
> >
> > --- In l...@yahoogroups.com
> >, "mshadow65"
> > wrote:
> > >
> > >
> > > Hi everyone!
> > >
> > > I'm using a LPC908 chip and i found problems using
> > > the internal RC oscillator.
> > > On user manual i can read it is factory-trimmed to 7.372.800
Mhz
> > > but, generating the baud rate using the internal BRG, the
frequency
> > > seems to be quite different, at least 1mhz less.
> > > Obviously i dont use the TRIM register
> > >
> > > Do anyone discovered a similar problem using the UART and BRG?
> > >
> > > Furno Gianluca
> > > ----------------------------------------------------------
> > > Furno G.Luca
> > > MicroSHADOW Research (uS)
> > > Development dept.
> > > Via Garibaldi, 25
> > > 19020 Ceparana (SP) - ITALY
> > > Tel : +39(0187)940951
> > > Mobile : 3337665111
> > > e-mail : info@
> > > web : www.microshadow.com
> > > ----------------------------------------------------------
>
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
try it as soon as I can get back to it.
--- In l...@yahoogroups.com, Jan Waclawek
>
> Actually, have you (Kevin or Furno) tried to read out the value of
TRIM?
>
> wek
>
> Kevin wrote:
> >
> >
> > Hi Furno,
> >
> > I'm using a LPC903 and found the same problem, the formula for
> > calculating the values for BRGR0, BRGR1 says it should be 0x0030
for
> > an 115,200 baud rate but I had to set it to 0x0034 to make it
work.
> >
> > If you have access to an oscilloscope you could just adjust the
> > values until you get the right pulse width.
> >
> > Kevin
> >
> > --- In l...@yahoogroups.com
> >
> > wrote:
> > >
> > >
> > > Hi everyone!
> > >
> > > I'm using a LPC908 chip and i found problems using
> > > the internal RC oscillator.
> > > On user manual i can read it is factory-trimmed to 7.372.800
Mhz
> > > but, generating the baud rate using the internal BRG, the
frequency
> > > seems to be quite different, at least 1mhz less.
> > > Obviously i dont use the TRIM register
> > >
> > > Do anyone discovered a similar problem using the UART and BRG?
> > >
> > > Furno Gianluca
> > > ----------------------------------------------------------
> > > Furno G.Luca
> > > MicroSHADOW Research (uS)
> > > Development dept.
> > > Via Garibaldi, 25
> > > 19020 Ceparana (SP) - ITALY
> > > Tel : +39(0187)940951
> > > Mobile : 3337665111
> > > e-mail : info@
> > > web : www.microshadow.com
> > > ----------------------------------------------------------
>
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
Re: LPC908 System Clock Problem - Kevin - Sep 28 21:55:18 2006
I have two chips that I read the TRIM register on.
One reads 0xAE and the other reads 0xAD
--- In l...@yahoogroups.com, Jan Waclawek wrote:
>
> Actually, have you (Kevin or Furno) tried to read out the value of
TRIM?
>
> wek
>
> Kevin wrote:
> >
> >
> > Hi Furno,
> >
> > I'm using a LPC903 and found the same problem, the formula for
> > calculating the values for BRGR0, BRGR1 says it should be 0x0030
for
> > an 115,200 baud rate but I had to set it to 0x0034 to make it
work.
> >
> > If you have access to an oscilloscope you could just adjust the
> > values until you get the right pulse width.
> >
> > Kevin
> >
> > --- In l...@yahoogroups.com
> >, "mshadow65"
> > wrote:
> > >
> > >
> > > Hi everyone!
> > >
> > > I'm using a LPC908 chip and i found problems using
> > > the internal RC oscillator.
> > > On user manual i can read it is factory-trimmed to 7.372.800
Mhz
> > > but, generating the baud rate using the internal BRG, the
frequency
> > > seems to be quite different, at least 1mhz less.
> > > Obviously i dont use the TRIM register
> > >
> > > Do anyone discovered a similar problem using the UART and BRG?
> > >
> > > Furno Gianluca
> > > ----------------------------------------------------------
> > > Furno G.Luca
> > > MicroSHADOW Research (uS)
> > > Development dept.
> > > Via Garibaldi, 25
> > > 19020 Ceparana (SP) - ITALY
> > > Tel : +39(0187)940951
> > > Mobile : 3337665111
> > > e-mail : info@
> > > web : www.microshadow.com
> > > ----------------------------------------------------------
>
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
One reads 0xAE and the other reads 0xAD
--- In l...@yahoogroups.com, Jan Waclawek
>
> Actually, have you (Kevin or Furno) tried to read out the value of
TRIM?
>
> wek
>
> Kevin wrote:
> >
> >
> > Hi Furno,
> >
> > I'm using a LPC903 and found the same problem, the formula for
> > calculating the values for BRGR0, BRGR1 says it should be 0x0030
for
> > an 115,200 baud rate but I had to set it to 0x0034 to make it
work.
> >
> > If you have access to an oscilloscope you could just adjust the
> > values until you get the right pulse width.
> >
> > Kevin
> >
> > --- In l...@yahoogroups.com
> >
> > wrote:
> > >
> > >
> > > Hi everyone!
> > >
> > > I'm using a LPC908 chip and i found problems using
> > > the internal RC oscillator.
> > > On user manual i can read it is factory-trimmed to 7.372.800
Mhz
> > > but, generating the baud rate using the internal BRG, the
frequency
> > > seems to be quite different, at least 1mhz less.
> > > Obviously i dont use the TRIM register
> > >
> > > Do anyone discovered a similar problem using the UART and BRG?
> > >
> > > Furno Gianluca
> > > ----------------------------------------------------------
> > > Furno G.Luca
> > > MicroSHADOW Research (uS)
> > > Development dept.
> > > Via Garibaldi, 25
> > > 19020 Ceparana (SP) - ITALY
> > > Tel : +39(0187)940951
> > > Mobile : 3337665111
> > > e-mail : info@
> > > web : www.microshadow.com
> > > ----------------------------------------------------------
>
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )