Technical data

MOTOROLA MC68HC912B32
10 MC68HC912B32TS/D
3.2 Power Supply Pins
MC68HC912B32 power and ground pins are described below and summarized in Table 4.
3.2.1 Internal Power (V
DD
) and Ground (V
SS
)
Power is supplied to the MCU through V
DD
and V
SS
. Because fast signal transitions place high, short-
duration current demands on the power supply, use bypass capacitors with high-frequency character-
istics and place them as close to the MCU as possible. Bypass requirements depend on how heavily
the MCU pins are loaded.
3.2.2 External Power (V
DDX
) and Ground (V
SSX
)
External power and ground for I/O drivers. Because fast signal transitions place high, short-duration cur-
rent 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.
3.2.3 V
DDA
, V
SSA
Provides operating voltage and ground for the analog-to-digital converter. This allows the supply volt-
age to the A/D to be bypassed independently.
3.2.4 Analog-to-Digital Reference Voltages (V
RH
, V
RL
)
3.2.5 V
FP
Flash EEPROM programming voltage and supply voltage during normal operation.
3.2.6 V
PP
High voltage supply to EEPROM. Used to monitor charge pump output and testing. Not intended for
general applications use.
Table 4 MC68HC912B32 Power and Ground Connection Summary
Mnemonic Pin Number Description
V
DD
10, 47
Internal power and ground.
V
SS
11, 48
V
DDX
31, 78
External power and ground, supply to pin drivers.
V
SSX
30, 77
V
DDA
59
Operating voltage and ground for the analog-to-digital converter,
allows the supply voltage to the A/D to be bypassed independently.
V
SSA
60
V
RH
49
Reference voltages for the analog-to-digital converter.
V
RL
50
V
FP
69
Programming voltage for the Flash EEPROM and required supply
for normal operation.
V
PP
37
High voltage supply to EEPROM used for test purposes only in
special modes.