Freescale Semiconductor, Inc.
Pinout and Signal Descriptions
3.4 Power Supply Pins
68HC(9)12D60 power and ground pins are described below and
summarized in Table 3-1.
3.4.1 Internal Power (V ) and Ground (V )
DD
SS
Power is supplied to the MCU through V and V . Because fast signal
DD
SS
transitions place high, short-duration current demands on the power
supply, use bypass capacitors with high-frequency characteristics and
place them as close to the MCU as possible. Bypass requirements
depend on how heavily the MCU pins are loaded.
3.4.2 External Power (V
) and Ground (V
)
DDX
SSX
External power and ground for I/O drivers. Because fast signal
transitions place high, short-duration current demands on the power
supply, use bypass capacitors with high-frequency characteristics and
place them as close to the MCU as possible. Bypass requirements
depend on how heavily the MCU pins are loaded.
3.4.3 V
, V
SSA
DDA
Provides operating voltage and ground for the analog-to-digital
converter. This allows the supply voltage to the ATD to be bypassed
independently. Connecting V
to V if the ATD modules are not
DD
DDA
used will not result in an increase of power consumption.
3.4.4 Analog to Digital Reference Voltages (V , V )
RH
RL
V
V
, V : reference voltage high and low for ATD converter 0.
RL0
RH0
RH1
, V : reference voltage high and low for ATD converter 1.
RL1
If the ATD modules are not used, leaving V connected to V will not
RH
DD
result in an increase of power consumption.
Advance Information
42
68HC(9)12D60 — Rev 4.0
MOTOROLA
Pinout and Signal Descriptions
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