# XTAL question

**URL:** <https://community.sparkfun.com/t/xtal-question/12770>\
**Category:** MicroMod\
**Tags:** arm-lpc\
**Created:** [September 30, 2009, 6:29pm UTC](https://community.sparkfun.com/t/xtal-question/12770 "2009-09-30T18:29:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kender](https://avatars.discourse-cdn.com/v4/letter/k/34f0e0/32.png) [@kender](https://community.sparkfun.com/u/kender)\
**Post date:** [September 30, 2009, 6:29pm UTC](https://community.sparkfun.com/t/xtal-question/12770/1 "2009-09-30T18:29:06Z")

</div>

Can’t get a crystal to oscillate. LPC2368 has 12MHz crystal, 20pF load capacitance, 60 Ohm ESR (DigiKey X428-ND). 39pF caps to ground, as recommended by the user manual. In the beginning of the program I enable the oscillator (this code comes from the example for LPC2378, which comes with IAR Embedded Workbench):

```auto
// 1. Init OSC
SCS_bit.OSCRANGE = 0;
SCS_bit.OSCEN = 1;
// 2. Wait for OSC ready
while(!SCS_bit.OSCSTAT);

```

Execution hangs on the last line. When I check the crystal with the scope, both sides are at 3.3V.

Any suggestion or insight is greatly appreciated!

- Nick

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<div class="post-metadata">

**Author:** ![cfb](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@cfb](https://community.sparkfun.com/u/cfb)\
**Post date:** [October 1, 2009, 12:22am UTC](https://community.sparkfun.com/t/xtal-question/12770/2 "2009-10-01T00:22:11Z")

</div>

> kender:  
> Can’t get a crystal to oscillate.
> 
> …
> 
> Any suggestion or insight is greatly appreciated!

A resolution of this problem can be seen at:

[http://tech.groups.yahoo.com/group/lpc2 … sage/44941](http://tech.groups.yahoo.com/group/lpc2000/message/44941)