Datasheet

MC9S12DT128B Device User Guide — V01.09
NOTE: All VSS pins must be connected together in the application.
2.4.1 VDDX,VSSX — Power & Ground Pins for I/O Drivers
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.
2.4.2 VDDR, VSSR — Power & Ground Pins for I/O Drivers & for Internal
Voltage Regulator
External power and ground for I/O drivers and input to the internal voltage regulator. 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.
2.4.3 VDD1, VDD2, VSS1, VSS2 — Core Power Pins
Power is supplied to the MCU through VDD and VSS. 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. This 2.5V supply is derived from the
internal voltage regulator. There is no static load on those pins allowed. The internal voltage regulator is
turned off, if VREGEN is tied to ground.
NOTE: No load allowed except for bypass capacitors.
VDDR 41 5.0V
External power and ground, supply to pin drivers and internal
voltage regulator.
VSSR 40 0V
VDDX 107 5.0V
External power and ground, supply to pin drivers.
VSSX 106 0V
VDDA 83 5.0V Operating voltage and ground for the analog-to-digital
converters and the reference for the internal voltage regulator,
allows the supply voltage to the A/D to be bypassed
independently.
VSSA 86 0V
VRL 85 0V
Reference voltages for the analog-to-digital converter.
VRH 84 5.0V
VDDPLL 43 2.5V Provides operating voltage and ground for the Phased-Locked
Loop. This allows the supply voltage to the PLL to be
bypassed independently. Internal power and ground
generated by internal regulator.
VSSPLL 45 0V
VREGEN 97 5V Internal Voltage Regulator enable/disable
Mnemonic
Pin Number
Nominal
Voltage
Description
112-pin QFP
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
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