03.08.2013 Views

MC9S12VR-Family - Data Sheet - Freescale Semiconductor

MC9S12VR-Family - Data Sheet - Freescale Semiconductor

MC9S12VR-Family - Data Sheet - Freescale Semiconductor

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

S12 Clock, Reset and Power Management Unit (S12CPMU_UHV)<br />

4.4.5 External Oscillator<br />

4.4.5.1 Enabling the External Oscillator<br />

An example of how to use the oscillator as Bus Clock is shown in Figure 4-36.<br />

OSCE<br />

EXTAL<br />

UPOSC<br />

OSCCLK<br />

PLLSEL<br />

Core<br />

Clock<br />

Figure 4-36. Enabling the external oscillator<br />

enable external oscillator by writing OSCE bit to one.<br />

crystal/resonator starts oscillating<br />

based on PLL Clock<br />

UPOSC flag is set upon successful start of oscillation<br />

select OSCCLK as Core/Bus Clock by writing PLLSEL to zero<br />

based on OSCCLK<br />

<strong>MC9S12VR</strong> <strong>Family</strong> Reference Manual, Rev. 2.8<br />

166 <strong>Freescale</strong> <strong>Semiconductor</strong>

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!