MC9S12KG128 Datasheet, PDF (215/600 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 6 Pierce Oscillator (S12OSCLCPV1)
EXTAL input frequency. In full stop mode (PSTP = 0), the EXTAL pin is pulled down by an internal
resistor of typical 200 kΩ.
NOTE
Freescale recommends an evaluation of the application board and chosen
resonator or crystal by the resonator or crystal supplier.
Loop controlled circuit is not suited for overtone resonators and crystals.
EXTAL
MCU
C1
Crystal or
Ceramic Resonator
XTAL
C2
V_SSPLL
Figure 6-2. Loop Controlled Pierce Oscillator Connections (XCLKS = 0)
NOTE
Full swing Pierce circuit is not suited for overtone resonators and crystals
without a careful component selection.
EXTAL
C1
MCU
XTAL
RB
RS*
Crystal or
Ceramic Resonator
C2
V_SSPLL
* R_s can be zero (shorted) when use with higher frequency crystals.
Refer to manufacturer’s data.
Figure 6-3. Full Swing Pierce Oscillator Connections (XCLKS = 1)
EXTAL
MCU
XTAL
CMOS Compatible
External Oscillator
(V_DDPLL Level)
Not Connected
Figure 6-4. External Clock Connections (XCLKS = 1)
MC9S12KG128 Data Sheet, Rev. 1.15
Freescale Semiconductor
215