Hi all
I was just wondering why there is no VBAT pin and Crystal inputs in LPC2129. If
there in RTC on chip then Battery backup and crystal is a must. Can you pls help
me understand what is the matter. I am tired searching the topic in user
manuals, errata sheets and datasheets of LPC21XX.
thanks
Anil
RTC in LPC2129
Started by ●August 16, 2009
Reply by ●August 16, 20092009-08-16
--- In l..., "anilupretidae" wrote:
>
> Hi all
> I was just wondering why there is no VBAT pin and Crystal inputs in LPC2129. If there in RTC on chip then Battery backup and crystal is a must. Can you pls help me understand what is the matter. I am tired searching the topic in user manuals, errata sheets and datasheets of LPC21XX.
>
> thanks
>
> Anil
>
Maybe the RTC Usage Notes on page 252 of the User Manual will help.
There is no backup battery provision and the RTC uses the VPB clock.
Richard
>
> Hi all
> I was just wondering why there is no VBAT pin and Crystal inputs in LPC2129. If there in RTC on chip then Battery backup and crystal is a must. Can you pls help me understand what is the matter. I am tired searching the topic in user manuals, errata sheets and datasheets of LPC21XX.
>
> thanks
>
> Anil
>
Maybe the RTC Usage Notes on page 252 of the User Manual will help.
There is no backup battery provision and the RTC uses the VPB clock.
Richard
Reply by ●August 16, 20092009-08-16
The external VBAT + RTC is something very useful for some designs, because
if you need to add an external RTC chip your budget increases, just a little
bit,
but increases.. :)
2009/8/16 rtstofer
> --- In l... ,
> "anilupretidae" wrote:
> >
> > Hi all
> > I was just wondering why there is no VBAT pin and Crystal inputs in
> LPC2129. If there in RTC on chip then Battery backup and crystal is a must.
> Can you pls help me understand what is the matter. I am tired searching the
> topic in user manuals, errata sheets and datasheets of LPC21XX.
> >
> > thanks
> >
> > Anil
> > Maybe the RTC Usage Notes on page 252 of the User Manual will help.
>
> There is no backup battery provision and the RTC uses the VPB clock.
>
> Richard
>
>
>
--
Miguel Angel Ajo Pelayo
http://www.nbee.es
+34 91 120 1798
+34 636 52 25 69
skype: ajoajoajo
if you need to add an external RTC chip your budget increases, just a little
bit,
but increases.. :)
2009/8/16 rtstofer
> --- In l... ,
> "anilupretidae" wrote:
> >
> > Hi all
> > I was just wondering why there is no VBAT pin and Crystal inputs in
> LPC2129. If there in RTC on chip then Battery backup and crystal is a must.
> Can you pls help me understand what is the matter. I am tired searching the
> topic in user manuals, errata sheets and datasheets of LPC21XX.
> >
> > thanks
> >
> > Anil
> > Maybe the RTC Usage Notes on page 252 of the User Manual will help.
>
> There is no backup battery provision and the RTC uses the VPB clock.
>
> Richard
>
>
>
--
Miguel Angel Ajo Pelayo
http://www.nbee.es
+34 91 120 1798
+34 636 52 25 69
skype: ajoajoajo
Reply by ●August 17, 20092009-08-17
Thanks.
Yes its written in user's manual that there is no provision for battery for LPC2129. If chip power is lost, time is gone! Out of so many pins a VBAT pin would have solved this big problem. Only an external RTC will solve my problem.
anil
--- In l..., "rtstofer" wrote:
>
> --- In l..., "anilupretidae" wrote:
> >
> > Hi all
> > I was just wondering why there is no VBAT pin and Crystal inputs in LPC2129. If there in RTC on chip then Battery backup and crystal is a must. Can you pls help me understand what is the matter. I am tired searching the topic in user manuals, errata sheets and datasheets of LPC21XX.
> >
> > thanks
> >
> > Anil
> > Maybe the RTC Usage Notes on page 252 of the User Manual will help.
>
> There is no backup battery provision and the RTC uses the VPB clock.
>
> Richard
>
Yes its written in user's manual that there is no provision for battery for LPC2129. If chip power is lost, time is gone! Out of so many pins a VBAT pin would have solved this big problem. Only an external RTC will solve my problem.
anil
--- In l..., "rtstofer" wrote:
>
> --- In l..., "anilupretidae" wrote:
> >
> > Hi all
> > I was just wondering why there is no VBAT pin and Crystal inputs in LPC2129. If there in RTC on chip then Battery backup and crystal is a must. Can you pls help me understand what is the matter. I am tired searching the topic in user manuals, errata sheets and datasheets of LPC21XX.
> >
> > thanks
> >
> > Anil
> > Maybe the RTC Usage Notes on page 252 of the User Manual will help.
>
> There is no backup battery provision and the RTC uses the VPB clock.
>
> Richard
>
Reply by ●August 17, 20092009-08-17
--- In l..., "anilupretidae" wrote:
>
> Thanks.
>
> Yes its written in user's manual that there is no provision for battery for LPC2129. If chip power is lost, time is gone! Out of so many pins a VBAT pin would have solved this big problem. Only an external RTC will solve my problem.
> anil
>
> --- In l..., "rtstofer" wrote:
> >
> > --- In l..., "anilupretidae" wrote:
> > >
> > > Hi all
> > > I was just wondering why there is no VBAT pin and Crystal inputs in LPC2129. If there in RTC on chip then Battery backup and crystal is a must. Can you pls help me understand what is the matter. I am tired searching the topic in user manuals, errata sheets and datasheets of LPC21XX.
> > >
> > > thanks
> > >
> > > Anil
> > >
> >
> > Maybe the RTC Usage Notes on page 252 of the User Manual will help.
> >
> > There is no backup battery provision and the RTC uses the VPB clock.
> >
> > Richard
> Hi, when the LPC2129 was announced there was only one small family of ARM microcontrollers that had less pins, the LPC2104/5/6 with 48-pin. You are saying "of so many pins", (un)fortunately all the pins have multiple functions, so providing a 32 kHz input and a Vbat would eliminate 3 of the functional pins.
What is the RTC good for? It is good for always on machinery that has an emergency backup if power fails. It is also good to log activity time of a machine and there are more possible uses of the RTC. It is however no good for applications that switch off the power for many hours / days / weekends and need to keep track of time.
Now, if you need such a device and all the features of the LPC2129 but at a lower price, have a look at the LPC2364. The only possible downside I see is the larger package but that one has enough pins to host a RTC with Vbat.
Cheers, Bob
http://www.lpc2000.com
>
> Thanks.
>
> Yes its written in user's manual that there is no provision for battery for LPC2129. If chip power is lost, time is gone! Out of so many pins a VBAT pin would have solved this big problem. Only an external RTC will solve my problem.
> anil
>
> --- In l..., "rtstofer" wrote:
> >
> > --- In l..., "anilupretidae" wrote:
> > >
> > > Hi all
> > > I was just wondering why there is no VBAT pin and Crystal inputs in LPC2129. If there in RTC on chip then Battery backup and crystal is a must. Can you pls help me understand what is the matter. I am tired searching the topic in user manuals, errata sheets and datasheets of LPC21XX.
> > >
> > > thanks
> > >
> > > Anil
> > >
> >
> > Maybe the RTC Usage Notes on page 252 of the User Manual will help.
> >
> > There is no backup battery provision and the RTC uses the VPB clock.
> >
> > Richard
> Hi, when the LPC2129 was announced there was only one small family of ARM microcontrollers that had less pins, the LPC2104/5/6 with 48-pin. You are saying "of so many pins", (un)fortunately all the pins have multiple functions, so providing a 32 kHz input and a Vbat would eliminate 3 of the functional pins.
What is the RTC good for? It is good for always on machinery that has an emergency backup if power fails. It is also good to log activity time of a machine and there are more possible uses of the RTC. It is however no good for applications that switch off the power for many hours / days / weekends and need to keep track of time.
Now, if you need such a device and all the features of the LPC2129 but at a lower price, have a look at the LPC2364. The only possible downside I see is the larger package but that one has enough pins to host a RTC with Vbat.
Cheers, Bob
http://www.lpc2000.com
Reply by ●August 17, 20092009-08-17
> -----Original Message-----
> From: l...
> [mailto:l...]On Behalf
> Of lpc2100_fan
> Sent: Sunday, August 16, 2009 11:16 PM
> To: l...
> Subject: [lpc2000] Re: RTC in LPC2129
> --- In l..., "anilupretidae" wrote:
> >
> > Thanks.
> >
> > Yes its written in user's manual that there is no provision
> for battery for LPC2129. If chip power is lost, time is gone!
> Out of so many pins a VBAT pin would have solved this big
> problem. Only an external RTC will solve my problem.
> >
> >
> > anil
> >
> > --- In l..., "rtstofer" wrote:
> > >
> > > --- In l..., "anilupretidae" wrote:
> > > >
> > > > Hi all
> > > > I was just wondering why there is no VBAT pin and
> Crystal inputs in LPC2129. If there in RTC on chip then
> Battery backup and crystal is a must. Can you pls help me
> understand what is the matter. I am tired searching the topic
> in user manuals, errata sheets and datasheets of LPC21XX.
> > > >
> > > > thanks
> > > >
> > > > Anil
> > > >
> > >
> > > Maybe the RTC Usage Notes on page 252 of the User Manual
> will help.
> > >
> > > There is no backup battery provision and the RTC uses the
> VPB clock.
> > >
> > > Richard
> > >
> >
> Hi, when the LPC2129 was announced there was only one small
> family of ARM microcontrollers that had less pins, the
> LPC2104/5/6 with 48-pin. You are saying "of so many pins",
> (un)fortunately all the pins have multiple functions, so
> providing a 32 kHz input and a Vbat would eliminate 3 of the
> functional pins.
> What is the RTC good for? It is good for always on machinery
> that has an emergency backup if power fails. It is also good
> to log activity time of a machine and there are more possible
> uses of the RTC. It is however no good for applications that
> switch off the power for many hours / days / weekends and
> need to keep track of time.
> Now, if you need such a device and all the features of the
> LPC2129 but at a lower price, have a look at the LPC2364. The
> only possible downside I see is the larger package but that
> one has enough pins to host a RTC with Vbat.
>
> Cheers, Bob
>
> http://www.lpc2000.com
>
Or, look at the LPC2148 which is in the same size package
with full support for the RTC. But, I can't vouch for if
the functionality is the same, as I am not familiar with
the LPC2129.
What I like about NXP, is there are quite a few ARM offerings
with slightly different features, but if the perhipherals
exist on the chips, usually the same driver code will work
for them.
Mike
> From: l...
> [mailto:l...]On Behalf
> Of lpc2100_fan
> Sent: Sunday, August 16, 2009 11:16 PM
> To: l...
> Subject: [lpc2000] Re: RTC in LPC2129
> --- In l..., "anilupretidae" wrote:
> >
> > Thanks.
> >
> > Yes its written in user's manual that there is no provision
> for battery for LPC2129. If chip power is lost, time is gone!
> Out of so many pins a VBAT pin would have solved this big
> problem. Only an external RTC will solve my problem.
> >
> >
> > anil
> >
> > --- In l..., "rtstofer" wrote:
> > >
> > > --- In l..., "anilupretidae" wrote:
> > > >
> > > > Hi all
> > > > I was just wondering why there is no VBAT pin and
> Crystal inputs in LPC2129. If there in RTC on chip then
> Battery backup and crystal is a must. Can you pls help me
> understand what is the matter. I am tired searching the topic
> in user manuals, errata sheets and datasheets of LPC21XX.
> > > >
> > > > thanks
> > > >
> > > > Anil
> > > >
> > >
> > > Maybe the RTC Usage Notes on page 252 of the User Manual
> will help.
> > >
> > > There is no backup battery provision and the RTC uses the
> VPB clock.
> > >
> > > Richard
> > >
> >
> Hi, when the LPC2129 was announced there was only one small
> family of ARM microcontrollers that had less pins, the
> LPC2104/5/6 with 48-pin. You are saying "of so many pins",
> (un)fortunately all the pins have multiple functions, so
> providing a 32 kHz input and a Vbat would eliminate 3 of the
> functional pins.
> What is the RTC good for? It is good for always on machinery
> that has an emergency backup if power fails. It is also good
> to log activity time of a machine and there are more possible
> uses of the RTC. It is however no good for applications that
> switch off the power for many hours / days / weekends and
> need to keep track of time.
> Now, if you need such a device and all the features of the
> LPC2129 but at a lower price, have a look at the LPC2364. The
> only possible downside I see is the larger package but that
> one has enough pins to host a RTC with Vbat.
>
> Cheers, Bob
>
> http://www.lpc2000.com
>
Or, look at the LPC2148 which is in the same size package
with full support for the RTC. But, I can't vouch for if
the functionality is the same, as I am not familiar with
the LPC2129.
What I like about NXP, is there are quite a few ARM offerings
with slightly different features, but if the perhipherals
exist on the chips, usually the same driver code will work
for them.
Mike
Reply by ●August 17, 20092009-08-17
--- In l..., "Michael Anton" wrote:
>
> > -----Original Message-----
> > From: l...
> > [mailto:l...]On Behalf
> > Of lpc2100_fan
> > Sent: Sunday, August 16, 2009 11:16 PM
> > To: l...
> > Subject: [lpc2000] Re: RTC in LPC2129
> >
> >
> > --- In l..., "anilupretidae" wrote:
> > >
> > > Thanks.
> > >
> > > Yes its written in user's manual that there is no provision
> > for battery for LPC2129. If chip power is lost, time is gone!
> > Out of so many pins a VBAT pin would have solved this big
> > problem. Only an external RTC will solve my problem.
> > >
> > >
> > > anil
> > >
> > > --- In l..., "rtstofer" wrote:
> > > >
> > > > --- In l..., "anilupretidae" wrote:
> > > > >
> > > > > Hi all
> > > > > I was just wondering why there is no VBAT pin and
> > Crystal inputs in LPC2129. If there in RTC on chip then
> > Battery backup and crystal is a must. Can you pls help me
> > understand what is the matter. I am tired searching the topic
> > in user manuals, errata sheets and datasheets of LPC21XX.
> > > > >
> > > > > thanks
> > > > >
> > > > > Anil
> > > > >
> > > >
> > > > Maybe the RTC Usage Notes on page 252 of the User Manual
> > will help.
> > > >
> > > > There is no backup battery provision and the RTC uses the
> > VPB clock.
> > > >
> > > > Richard
> > > >
> > >
> > Hi, when the LPC2129 was announced there was only one small
> > family of ARM microcontrollers that had less pins, the
> > LPC2104/5/6 with 48-pin. You are saying "of so many pins",
> > (un)fortunately all the pins have multiple functions, so
> > providing a 32 kHz input and a Vbat would eliminate 3 of the
> > functional pins.
> > What is the RTC good for? It is good for always on machinery
> > that has an emergency backup if power fails. It is also good
> > to log activity time of a machine and there are more possible
> > uses of the RTC. It is however no good for applications that
> > switch off the power for many hours / days / weekends and
> > need to keep track of time.
> > Now, if you need such a device and all the features of the
> > LPC2129 but at a lower price, have a look at the LPC2364. The
> > only possible downside I see is the larger package but that
> > one has enough pins to host a RTC with Vbat.
> >
> > Cheers, Bob
> >
> > http://www.lpc2000.com
> >
> Or, look at the LPC2148 which is in the same size package
> with full support for the RTC. But, I can't vouch for if
> the functionality is the same, as I am not familiar with
> the LPC2129.
>
> What I like about NXP, is there are quite a few ARM offerings
> with slightly different features, but if the perhipherals
> exist on the chips, usually the same driver code will work
> for them.
>
> Mike
>
Be careful with the current draw on the vbat pin though. I have found the external rtc parts have significantly lower current draw. I am not sure if this matters in your case but it did for my last design.
TLM
>
> > -----Original Message-----
> > From: l...
> > [mailto:l...]On Behalf
> > Of lpc2100_fan
> > Sent: Sunday, August 16, 2009 11:16 PM
> > To: l...
> > Subject: [lpc2000] Re: RTC in LPC2129
> >
> >
> > --- In l..., "anilupretidae" wrote:
> > >
> > > Thanks.
> > >
> > > Yes its written in user's manual that there is no provision
> > for battery for LPC2129. If chip power is lost, time is gone!
> > Out of so many pins a VBAT pin would have solved this big
> > problem. Only an external RTC will solve my problem.
> > >
> > >
> > > anil
> > >
> > > --- In l..., "rtstofer" wrote:
> > > >
> > > > --- In l..., "anilupretidae" wrote:
> > > > >
> > > > > Hi all
> > > > > I was just wondering why there is no VBAT pin and
> > Crystal inputs in LPC2129. If there in RTC on chip then
> > Battery backup and crystal is a must. Can you pls help me
> > understand what is the matter. I am tired searching the topic
> > in user manuals, errata sheets and datasheets of LPC21XX.
> > > > >
> > > > > thanks
> > > > >
> > > > > Anil
> > > > >
> > > >
> > > > Maybe the RTC Usage Notes on page 252 of the User Manual
> > will help.
> > > >
> > > > There is no backup battery provision and the RTC uses the
> > VPB clock.
> > > >
> > > > Richard
> > > >
> > >
> > Hi, when the LPC2129 was announced there was only one small
> > family of ARM microcontrollers that had less pins, the
> > LPC2104/5/6 with 48-pin. You are saying "of so many pins",
> > (un)fortunately all the pins have multiple functions, so
> > providing a 32 kHz input and a Vbat would eliminate 3 of the
> > functional pins.
> > What is the RTC good for? It is good for always on machinery
> > that has an emergency backup if power fails. It is also good
> > to log activity time of a machine and there are more possible
> > uses of the RTC. It is however no good for applications that
> > switch off the power for many hours / days / weekends and
> > need to keep track of time.
> > Now, if you need such a device and all the features of the
> > LPC2129 but at a lower price, have a look at the LPC2364. The
> > only possible downside I see is the larger package but that
> > one has enough pins to host a RTC with Vbat.
> >
> > Cheers, Bob
> >
> > http://www.lpc2000.com
> >
> Or, look at the LPC2148 which is in the same size package
> with full support for the RTC. But, I can't vouch for if
> the functionality is the same, as I am not familiar with
> the LPC2129.
>
> What I like about NXP, is there are quite a few ARM offerings
> with slightly different features, but if the perhipherals
> exist on the chips, usually the same driver code will work
> for them.
>
> Mike
>
Be careful with the current draw on the vbat pin though. I have found the external rtc parts have significantly lower current draw. I am not sure if this matters in your case but it did for my last design.
TLM
