MC9S12Q FREESCALE [Freescale Semiconductor, Inc], MC9S12Q Datasheet - Page 345

• Manufacturer Part Number: MC9S12Q
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

11.2.3
The XCLKS is an input signal which controls whether a crystal in combination with the internal Colpitts
(low power) oscillator is used or whether the Pierce oscillator/external clock circuitry is used. The XCLKS
signal is sampled during reset with the rising edge of RESET.
sampled XCLKS signal. Refer to the device overview chapter for polarity of the XCLKS pin.
Freescale Semiconductor
XCLKS — Colpitts/Pierce Oscillator Selection Signal
MCU
* Rs can be zero (shorted) when used with higher frequency crystals.
Refer to manufacturer’s data.
Figure 11-2. Pierce Oscillator Connections (XCLKS = 1)
Figure 11-3. External Clock Connections (XCLKS = 1)
EXTAL
XCLKS
XTAL
0
1
Table 11-1. Clock Selection Based on XCLKS
MCU
EXTAL
Colpitts oscillator selected
Pierce oscillator/external clock selected
RS*
XTAL
RB
MC9S12Q128
Not Connected
Rev 1.09
Description
CMOS-Compatible
External Oscillator
(V
Crystal or Ceramic
Resonator
DDPLL
Level)
Table 11-1
C3
C4
Chapter 11 Oscillator (OSCV2) Block Description
V
SSPLL
lists the state coding of the
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