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Configuring the oscillator pins as active low GPIOs in S912ZVLA MCU

Hello all,

external oscillator is disabled and system clock runs from internal oscillator. Electrical team is asking possiblity to configure the oscillator pins as active low GPIOs to minimize current consumption .

I was researching whether it is possible . As per my analysis ,

On S12X / classic S12:

Clock pins are digital pads first
Oscillator is just a peripheral
When disabled → GPIO output drivers are enabled

On S12VLA (MagniV):

Clock pins are analog pads first
Oscillator permanently owns the pad
GPIO never gets output control

is my understanding correct ?

Re: Configuring the oscillator pins as active low GPIOs in S912ZVLA MCU

Thank you .. I am having S912ZVLA12A MCU. As per your explanation --is this MCU part of classic s12 which doesnt support configuring XTAL & EXTAL pins are acitve low

or

is this MCU part of S12G and S12P devices (180 nm technology) and the MagniV family (S12Z) ? is configuring XTAL & EXTAL pins as acitve low works here?

Thanks,

Pallavi Y B

Re: Configuring the oscillator pins as active low GPIOs in S912ZVLA MCU

Hi,

The “classic” S12 families do not provide an internal oscillator intended for system clock usage (250 nm technology). Moreover, these devices do not support alternative pin functions on the XTAL and EXTAL pins.

This capability was introduced with the S12G and S12P devices (180 nm technology) and the MagniV family (S12Z). These devices start with the internal oscillator enabled, while the external oscillator is optional.

Therefore, XTAL and EXTAL operate as alternative function pins, and the MCU starts with PE0 and PE1 on these pins configured as inputs (DDRE), with pull‑down enabled (PERE and PPSE).

Best regards,
Ladislav

Re: Configuring the oscillator pins as active low GPIOs in S912ZVLA MCU

hello Lama,

Can you please confirm above point ?