mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 203

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

5.2.3
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
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 5-2. Pierce Oscillator Connections (XCLKS = 1)
EXTAL
Figure 5-3. External Clock Connections (XCLKS = 1)
XCLKS
XTAL
0
1
Table 5-1. Clock Selection Based on XCLKS
Chapter 1, “MC9S12E256 Device Overview (MC9S12E256DGV1)”
MCU
EXTAL
Colpitts oscillator selected
Pierce oscillator/external clock selected
MC9S12E256 Data Sheet, Rev. 1.08
RS*
XTAL
RB
Not Connected
Description
CMOS-Compatible
External Oscillator
(V
Crystal or Ceramic
Resonator
DDPLL
Level)
Table 5-1
C3
C4
V
SSPLL
lists the state coding of the
Chapter 5 Oscillator (OSCV2)
for
203