topic Problem on LPC54608Expresso, PLL's will not lock in LPC Microcontrollers

Problem on LPC54608Expresso, PLL's will not lock

carstengroen — Fri, 23 Dec 2016 08:25:42 GMT

I have been going thru the various test programs for the LPC54608Expresso board and I'm having some problems with the "periph_clkout" sample. I can get the CLKOUT working fine, but only if I disable the PLL code (both system and audio).

If any of the Chip_Clock_SetAudioPLLFreq() or Chip_Clock_SetupSystemPLLPrec() is called (the two lines with the breakpoints in the attached screendump, the code will hang forever waiting for PLL lock (both Audio and System)

Am I doing something wrong, or are any of you able to reproduce this ?

Re: Problem on LPC54608Expresso, PLL's will not lock

eli_hughes — Mon, 26 Dec 2016 01:21:58 GMT

Look in the board support project for "board.h"

Look for"

#define BOARD_MAINCLOCKRATE

Is it set to 96MHz? Change it to something higher (180000000) . The worked for me.

Re: Problem on LPC54608Expresso, PLL's will not lock

carstengroen — Mon, 26 Dec 2016 10:16:14 GMT

Thanks Eli,

I tried that also, but no success! I also did see that the project was set to LPC54113 as target, that was also changed, but no success.

What I did instead was to take the sysinit_lpc5460x.c from ARM\Pack\Keil\LPC54000_DFP\2.2.0\LPCOpen\lpc5460x\chip_5460x\src

and tweak that, and this worked. I have not looked into what the difference is, it might be that I was tricked somehow :smileywink:

Anyway, I got the chip running at 180 MHz (even tried 200 MHz for a few minutes which ran ok, but is of course out of spec!).

Eli, what speed do you run the SDRAM at ? It seems that 75 MHz is the maximum I can get it running at, if I go above 150 MHz clock, I need to do a divide by 3 to the EMC controller. At 150 MHz it runs fine with divide by 2 (75 MHz) ??