Freescale Semiconductor, Inc.
General Description
Pin Functions
1.7 Pin Functions
This subsection describes the MC68HC705C8A signals. Reference is
made, where applicable, to other sections that contain more detail about
the function being performed.
1.7.1 VDD and VSS
VDD and VSS are the power supply and ground pins. The MCU operates
from a single power supply.
V+
Very fast signal transitions occur
on the MCU pins, placing high
V
DD
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 shown in
Figure 1-7.
+
C2
MCU
C1
V
SS
Figure 1-7. Bypassing Layout
Recommendation
1.7.2 VPP
This pin provides the programming voltage to the EPROM array. For
normal operation, VPP shuld be tied to VDD.
NOTE: Connecting the VPP pin (programming voltage) to VSS (ground) could
result in damage to the MCU.
MC68HC705C8A — Rev. 3
MOTOROLA
Technical Data
General Description
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