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MCB2300 strange behaviour - erratic speed?!

Started by active_si May 3, 2009
Hi all!

I own a MCB2300 board (version 3) and I have noticed lately that sometimes when I turn on the board the speed is not as it is supposed to be - about 20x faster.

I have a RTC interrupt setup for every second and normally the interrupr outputs 1line/second to my UART1 but when the speed is not correct I get about 20 lines/second and of course everything else doesn't work as it is supposed to.

After I "reboot" (switch off/on) the board the speed is as it is supposed to be - MCU reset only doesn't help.

Did anyone else have any similar problems? What could be causing this?

any help will be appreciated.

Re, Uros

An Engineer's Guide to the LPC2100 Series

--- In l..., "active_si" wrote:
>
> Hi all!
>
> I own a MCB2300 board (version 3) and I have noticed lately that
sometimes when I turn on the board the speed is not as it is
supposed to be - about 20x faster.
>
> I have a RTC interrupt setup for every second and normally the
interrupr outputs 1line/second to my UART1 but when the speed is not
correct I get about 20 lines/second and of course everything else
doesn't work as it is supposed to.
>
> After I "reboot" (switch off/on) the board the speed is as it is
supposed to be - MCU reset only doesn't help.
>
> Did anyone else have any similar problems? What could be causing
this?

I've recently successfully completed testing Armaide on an LPC2378
ready for the next release. In the process I discovered these are
much more versatile (and hence, much more complex) than the
LPC2100/2200 MCUs in the way they need to be setup for processor
clock speed, PLL setup etc. Also, there are now individual clock
dividers for different peripherals that can be programmed.

Read Chapter 4. 'LPC23XX Clocking and Power Control' in the NXP
LPC23xx User Manual UM10211 for all of the relevant information and
then check the setup code you are using.

Chris Burrows
CFB Software
Armaide: LPC2000 Oberon-07 Development System
http://www.cfbsoftware.com/armaide

Hi!

The thing is that this happens without any code change.
I.e. when I'm not at home I turn-off the board (pull out the USB power) when I switch the board on, it may work OK but it may also happen that it will not and it will be running at this strange speed.
Then I switch the board off and on again and usually that helps and the speed is as it should be.

Now I am wondering is this is actually a software problem or could it be a hardware problem?

Any insights would be helpful!

Thanks!

--- In l..., "cfbsoftware1" wrote:
>
> --- In l..., "active_si" wrote:
> >
> > Hi all!
> >
> > I own a MCB2300 board (version 3) and I have noticed lately that
> sometimes when I turn on the board the speed is not as it is
> supposed to be - about 20x faster.
> >
> > I have a RTC interrupt setup for every second and normally the
> interrupr outputs 1line/second to my UART1 but when the speed is not
> correct I get about 20 lines/second and of course everything else
> doesn't work as it is supposed to.
> >
> > After I "reboot" (switch off/on) the board the speed is as it is
> supposed to be - MCU reset only doesn't help.
> >
> > Did anyone else have any similar problems? What could be causing
> this?
>
>
> I've recently successfully completed testing Armaide on an LPC2378
> ready for the next release. In the process I discovered these are
> much more versatile (and hence, much more complex) than the
> LPC2100/2200 MCUs in the way they need to be setup for processor
> clock speed, PLL setup etc. Also, there are now individual clock
> dividers for different peripherals that can be programmed.
>
> Read Chapter 4. 'LPC23XX Clocking and Power Control' in the NXP
> LPC23xx User Manual UM10211 for all of the relevant information and
> then check the setup code you are using.
>
> Chris Burrows
> CFB Software
> Armaide: LPC2000 Oberon-07 Development System
> http://www.cfbsoftware.com/armaide
>