LPC MicrocontrollersのトピックRe: LPC5528: Minimum operating frequency external crystal

LPC5528: Minimum operating frequency external crystal

airios_arno — Thu, 18 Feb 2021 08:00:06 GMT

We are designing a new product with the LPC5528JBD64 and noticed a discrepancy in the product datasheet (revision 2.0), regarding the minimum operating frequency of the external crystal oscillator.

On page 4, under Clock generation, it mentions a range of 12 MHz to 32 MHz.

However, in chapter 7.19.1 Clock sources, a range of 1 MHz to 32 MHz is specified.

The MCUXpresso Clock Config tool also expects me to enter at least 12 MHz, but that might have been based off of incorrect data as well.

Can someone from NXP maybe give me a definitive answer on what the minimum operating frequency for the external crystal oscillator is?

Thanks,
Arno

PS: I also noticed that there is a discrepancy with regards to the external clock input (25 MHz on page 4 and 24 MHz in the aforementioned chapter).

Re: LPC5528: Minimum operating frequency external crystal

xiangjun_rong — Thu, 18 Feb 2021 09:05:33 GMT

Hi, Arno,

I have checked the data sheet of LPC5528, there is a discrepancy for the minimum crystal frequency exactly, one part says the minimum crystal frequency is 1MHz, another part says it is 12mhz.

Anyway, I have asked the design team, I will answer you after I get feedback.

XiangJun Rong

Re: LPC5528: Minimum operating frequency external crystal

arno1 — Fri, 19 Feb 2021 08:24:43 GMT

One of our suppliers also contacted NXP regarding this issue and just reported back to us:
- For an external clock source the frequency range is 1 MHz - 24 MHz.
- For an external crystal oscillator the frequency range is 12 MHz - 32 MHz.

Re: LPC5528: Minimum operating frequency external crystal

xiangjun_rong — Fri, 19 Feb 2021 09:00:39 GMT

Hi, Arno,

This is feedback from AE team, hope it can help you.

For an external clock source, the frequency range is 1 MHz - 24 MHz. - For an external crystal oscillator the frequency range is 12 MHz - 32 MHz.

We will update the data sheet of LPC5528 later.

XiangJun Rong