LPC MicrocontrollersのトピックRe: RTC Crystal Frequency on LPC1549

RTC Crystal Frequency on LPC1549

lpcware — Wed, 15 Jun 2016 17:08:48 GMT

Content originally posted in LPCWare by celephicus on Sun Dec 07 17:37:12 MST 2014
We're confused, the LPC1500 user manual says that a RTC xtal of 32kHz xtal is required. But the Embedded Artists demo board uses 32.768kHz, in fact the LPC1700 user manual mentions this frequency as well. Come to think of it 32.000kHz xtals are not used much anywhere.

So I am assuming an error in the user manual and it is really 32.768kHz? Can someone confirm that 32.768kHz works?

Re: RTC Crystal Frequency on LPC1549

lpcware — Wed, 15 Jun 2016 17:08:49 GMT

Content originally posted in LPCWare by R2D2 on Sun Dec 07 18:23:15 MST 2014

Quote: celephicus
So I am assuming an error in the user manual and it is really 32.768kHz? Can someone confirm that 32.768kHz works?

Yes, we can :)

Re: RTC Crystal Frequency on LPC1549

lpcware — Wed, 15 Jun 2016 17:08:50 GMT

Content originally posted in LPCWare by celephicus on Sun Dec 07 18:38:58 MST 2014
Thank you R2D2. This will hopefully stop my collegue worrying that he needs to put an external RTC on his board.

Re: RTC Crystal Frequency on LPC1549

lpcware — Wed, 15 Jun 2016 17:08:50 GMT

Content originally posted in LPCWare by R2D2 on Sun Dec 07 18:49:13 MST 2014

Quote: celephicus
This will hopefully stop my collegue worrying that he needs to put an external RTC on his board.

:bigsmile:

I'm using a MCP79410 on my boards, a 'real' RTC...

Re: RTC Crystal Frequency on LPC1549

lpcware — Wed, 15 Jun 2016 17:08:51 GMT

Content originally posted in LPCWare by MarcVonWindscooting on Tue Dec 09 15:49:09 MST 2014

Quote: R2D2
I'm using a MCP79410 on my boards, a 'real' RTC...

1uA time-keeping, only. Nice.

What do you think about 'Micro Crystal Switzerland' devices like CV-3029-* ?

Marc

Re: RTC Crystal Frequency on LPC1549

lpcware — Wed, 15 Jun 2016 17:08:51 GMT

Content originally posted in LPCWare by R2D2 on Tue Dec 09 16:09:46 MST 2014

Quote: MarcVonWindscooting
What do you think about 'Micro Crystal Switzerland' devices like CV-3029-* ?

Is that something like RV-3029 :quest:

http://www.microcrystal.com/images/_PDF/5_Real-Time-Clock_RV/rv-3029-c2.pdf

Unfortunately a little bit expensive :((

Re: RTC Crystal Frequency on LPC1549

lpcware — Wed, 15 Jun 2016 17:08:52 GMT

Content originally posted in LPCWare by larryvc on Tue Dec 09 18:15:47 MST 2014

Quote: R2D2
I'm using a MCP79410 on my boards, a 'real' RTC...

On the device page

Quote:
##Leap year compensated to 2399

Hope we all make it! :)

Re: RTC Crystal Frequency on LPC1549

lpcware — Wed, 15 Jun 2016 17:08:52 GMT

Content originally posted in LPCWare by mc on Thu Dec 11 10:53:56 MST 2014
Hi celephicus,

Quote:
So I am assuming an error in the user manual and it is really 32.768kHz? Can someone confirm that 32.768kHz works?

Yes, I confirm, it works as mentioned by other users.