topic Re: HOW to using LPC54102 PLL in LPC Microcontrollers

HOW to using LPC54102 PLL

zhan8g — Sat, 02 Sep 2017 08:59:37 GMT

LPC54102 uses 32.768KHz, PLL to 12MHz, but after running for some time, the 12MHz master clock becomes 24MHz or something else. Why is that?

Re: HOW to using LPC54102 PLL

jeremyzhou — Tue, 05 Sep 2017 02:50:05 GMT

Hi a tom,

Thank you for your interest in NXP Semiconductor products and

for the opportunity to serve you.

I'd highly recommend you to use the visualize tool: Clocks Tool to configure the clock of the LPC54102.

Welcome to MCUXpresso | MCUXpresso Config Tools

Have a great day,
TIC

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Re: HOW to using LPC54102 PLL

zhan8g — Tue, 05 Sep 2017 07:19:57 GMT

thanks. My LPC54102 using an external clock 32.768KHz, PLL to 12MHz for the master clock and the asynchronous clock，the code using pllfract.c of NXP lpc5410x_xpresso54102_keil_iar_v3.03.000_16 from NXP web, but after running for some time, the 12MHz master clock becomes 24MHz or something else. IRC-12MHz is running for a long time, there is no problem. Now, there is a problem with the setPllRate function found in the pllfract.c file. Do you have a regular and stable setPllRate new function?

Re: HOW to using LPC54102 PLL

jeremyzhou — Tue, 05 Sep 2017 07:30:55 GMT

Hi a tom,

Thanks for your reply.

I think you use the LPCOpen library, and LPC54102 also has the KSDK library which is a new library, you can try it out.

Whether you can illustrate the steps to replicate the issue in details.

Welcome to MCUXpresso | MCUXpresso Config Tools

Have a great day,
TIC

Re: HOW to using LPC54102 PLL

zhan8g — Wed, 06 Sep 2017 10:49:59 GMT

thank you very munch.