topic PLL1 clock fail in LPC Microcontrollers

PLL1 clock fail

lpcware — Wed, 15 Jun 2016 18:27:15 GMT

Content originally posted in LPCWare by Cusko on Fri Mar 29 04:04:08 MST 2013
Hello,

We have some custom made boards with the LPC1857 and the LPC1837. And I found a problem with processor on same of the boards.
Description: The problematic processors can be programmed successfully via an UlinkPro debbuger. But the program won't run. I debugged the program and it stops in a while loop:
"while (!(LPC_CGU->PLL1_STAT & 1)); "
The other boards which are the same works just fine.
So I assume there is problem with PLL1 clock with some processors. Am I correct and what can we do?
Thanks!

Re: PLL1 clock fail

lpcware — Wed, 15 Jun 2016 18:27:17 GMT

Content originally posted in LPCWare by Wouter on Thu Apr 11 05:10:23 MST 2013

Hi Cusko,

The line "while (!(LPC_CGU->PLL1_STAT & 1));" waits for the PLL to lock. Assuming you use an external crystal as input, most likely you'll have a problem with the crystal not oscillating. Ensure proper connection from the CPU XTAL pins to the crystal and it's load capactors. Also verify that you are using the right value for your load capacitors (see: http://www.lpcware.com/content/faq/how-calculate-value-crystal-load-capacitors).

Regards,

Wouter