MCU pin configuration

[FreshmanNewbie]

In the datasheet of this MCU, on page 37,

it is mentioned as, "Note: To guarantee the XOSC32K behavior in crystal mode, PC00 must be static."



I've used the pin 1 (PA00) as a Clock oscillator input.

My questions:

1. What is the meaning of static? What does it mean PC00 must be static?
2. Is it OK with respect to the above NOTE point?

 

[KlausST]

Hi,

It depends on:
* which package you are using: Only valid for packages: TQFP-100, TFBGA-120, TQFP-128,
* what external device you are using: a bare XTAL (using XIN32 and XOUT32) or a XTAL_OSCILLATOR (using only XIN32)?

oscillator: no problem
bare XTAL: Don´t use PC00 as switching (changing states frequently) output or input.

I guess the signal of PC00 will couple into the oscillator and may cause problems (jitter ..)

So the signal on PC00 may be a slowly changing analog signal.
I guess it´s O.K. to use it to switch a LED ON and OFF (every couple of seconds), but it´s not O.K. to use it as PWM to dim a LED.

* Do a PDF search for "PC00", "PA00", "PA01", "XIN32", "XOUT32"
* read section 60.6.3

Klaus