MC68HC05K0 Datasheet, PDF (22/154 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Technical Data
Freescale Semiconductor, Inc.
1.6.1 V_DD and V_SS
V_DD and V_SS are the power supply and ground pins. The MCU operates
from a single 3.0-V to 6.0-V power supply.
Very fast signal transitions occur on the MCU pins, placing high
short-duration current demands on the power supply. To prevent noise
problems, take special care to provide good power supply bypassing at
the MCU. Place bypass capacitors as close to the MCU as possible, as
Figure 1-3 shows.
V_DD
+
MCU
C1
C2
V_SS
OSC1
OSC2
V_SS
C1 C2
V_DD
Note:
Actual layout varies according to component dimensions.
Figure 1-3. Bypassing Layout Recommendation
1.6.2 OSC1, OSC2, and PB1/OSC3
The OSC1, OSC2, and PB1/OSC3 pins are the control connections for
the 2-pin or 3-pin on-chip oscillator. The oscillator can be driven by any
of these:
• Crystal
• Ceramic resonator
• Resistor-capacitor (RC) combination
• External clock signal
The frequency of the internal oscillator is f_osc. The MCU divides the
internal oscillator output by two to produce the internal clock with a
frequency of f_op.
Technical Data
MC68HC05K0 • MC68HC05K1 — Rev. 2.0
General Description
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