MC68HC05P18A Datasheet, PDF (21/130 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
General Description
Functional Pin Description
The frequency, f_OSC, of the oscillator or external clock source is divided
by two to produce the internal PH2 bus clock operating frequency, f_OP.
The oscillator cannot be turned off by software if the stop-to-halt
conversion is enabled via mask option.
TO V_DD OR STOP
MCU
TO V_DD OR STOP
MCU
OSC1
4.7 MΩ
OSC2
OSC1
OSC2
UNCONNECTED
37 pF
37 pF
(a) Crystal or Ceramic
Resonator Connections
EXTERNAL CLOCK
(b) External Clock Source
Connections
Figure 1-3. Oscillator Connections
1.5.2.1 Crystal
The circuit in Figure 1-3 (a) shows a typical oscillator circuit for an
AT-cut, parallel resonant crystal.
NOTE:
The crystal manufacturer’s recommendations should be followed, as the
crystal parameters determine the external component values required to
provide maximum stability and reliable startup.
The load capacitance values used in the oscillator circuit design should
include all stray capacitances. Mount the crystal and components as
close as possible to the pins for startup stabilization and to minimize
output distortion.
MC68HC05P18A
General Description
For More Information On This Product,
Go to: www.freescale.com
Technical Data