Lpc2000

I am sorry.
The link is http://www.keil.com/mcb2130/mcb2130-schematics.pdf

I understand that in this case the resistor was used for limiting the drive.
I will take your suggestion about the value. (220K)

Thank you very much.
  ----- Original Message ----- 
  From: Arie de Muynck 
  To: lpc2000@yahoogroups.com 
  Sent: Wednesday, March 23, 2005 5:42 PM
  Subject: Re: [lpc2000] 560K in RTC XTAL circuit


  From: "Alejandro Fabricio Fernandez"
  > I am starting with 2138 uC.
  > I saw a sch from Jan Szymanski, I have a question for you.
  > You put a 560K resistor between the 32.768khz xtal and de uC.
  > Do you found that configuration in a Philips AN?

  Next time please could post a link to the circuit, to prevent unnecessary
  speculations...

  If the resistor is electrically between output and crystal, it is used to
  limit the drive to the crystal. Expecially the 32 kHz crystals can easily be
  overdriven and destroyed. But 560 K looks a bit high - I normally use 220
  kOhm.

  If is is beteen the input and output of the oscillator amplifier, it is a
  biasing resistor - and should normally be between 2.2 and 10M ohm.

  Regards,
  Arie de Muynck


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