We just found it... btw
It seems that the internal test mode controls are not reset to 0.
Keep in mind that those bits are not touched by the firmware and thus seem to go
in an undefined state.
These bits are bit 3 and 2 of the CCR register, their reset value is
'NC'. Bit 3 was set to '1' and bit 2 was set to
'0'.
Setting bit 3 to '0' solved our problem and setting it to
'1' caused it again.
So we will keep them at '0'.
--- In l..., Tim Mitchell wrote:
>
> ----Original Message----
> From: l...
> [mailto:l...] On Behalf Of firmware111
> Sent: 16 May 2013 11:10 To: l...
> Subject: [lpc2000] lpc1788 real time clock problem
>
> > Hi Guys,
> >
> > We have a product that uses the real time clock of the
> > lpc1788.
> > When the RTC is enabled it normally starts counting
> > seconds then minutes, hours and so on.
> >
> > But recently we got several lpc1788's that count all of
> > those at once. So the seconds, minutes, hours, days,
> > months and years are increment by 1 each second.
> >
> > A few days ago we got about 20 PCB's and 14 are working
> > ok, but 6 of them have this RTC problem.
> >
> > Maybe i'm doing something wrong, but does any one now of
> > this?
> > Interesting, I have experienced this problem on a single board out of a
batch of 25, and even after much investigation we could not find the cause. The
processor was an LPC1758 but the RTC will be the same I should think.
>
> If anyone else has seen this (or better, fixed it) it would be interesting to
know about it.
>
> --
> Tim Mitchell
>
