mc9s12hz256v2 Freescale Semiconductor, Inc, mc9s12hz256v2 Datasheet - Page 204

• Manufacturer Part Number: mc9s12hz256v2
• Description: Hcs12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 6 Oscillator (OSCV2)
6.2
This section lists and describes the signals that connect off chip.
6.2.1
These pins provide the operating voltage (V
allows the supply voltage to the OSC to be independently bypassed.
6.2.2
These pins provide the interface for either a crystal or a CMOS compatible clock to control the internal
clock generator circuitry. EXTAL is the external clock input or the input to the crystal oscillator amplifier.
XTAL is the output of the crystal oscillator amplifier. All the MCU internal system clocks are derived from
the EXTAL input frequency. In full stop mode (PSTP = 0) the EXTAL pin is pulled down by an internal
resistor of typical 200 k .
204
External Signal Description
V
EXTAL and XTAL — Clock/Crystal Source Pins
DDPLL
Freescale Semiconductor recommends an evaluation of the application
board and chosen resonator or crystal by the resonator or crystal supplier
The Crystal circuit is changed from standard.
The Colpitts circuit is not suited for overtone resonators and crystals.
The Pierce circuit is not suited for overtone resonators and crystals without
a careful component selection.
and V
MCU
Figure 6-1. Colpitts Oscillator Connections (XCLKS = 0)
* Due to the nature of a translated ground Colpitts oscillator
EXTAL
a DC voltage bias is applied to the crystal.
Please contact the crystal manufacturer for crystal DC bias
conditions and recommended capacitor value CDC.
XTAL
SSPLL
MC9S12HZ256 Data Sheet, Rev. 2.05
— PLL Operating Voltage, PLL Ground
CDC*
DDPLL
NOTE
NOTE
) and ground (V
C1
C2
V
SSPLL
Crystal or Ceramic
Resonator
SSPLL
) for the OSC circuitry. This
Freescale Semiconductor
.