Chapter 1 Device Overview (MC9S12XDP512V2)
MC9S12XDP512 Data Sheet, Rev. 2.11
Freescale Semiconductor 89
1.2.4.2 VDDR1, VDDR2, VSSR1, VSSR2 — Power and Ground Pins for I/O Driversand 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.
1.2.4.3 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 2.5-V 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.
1.2.4.4 VDDA, VSSA — Power Supply Pins for ATD and VREG
VDDA,V
SSA are the power supply and ground input pins for the voltage regulator and the analog-to-digital
converters.
1.2.4.5 VRH, VRL — ATD Reference Voltage Input Pins
VRH and VRL are the reference voltage input pins for the analog-to-digital converter.
1.2.4.6 VDDPLL, VSSPLL — Power Supply Pins for PLL
Provides operating voltage and ground for the oscillator and the phased-locked loop. This allows the
supply voltage to the oscillator and PLL to be bypassed independently. This 2.5-V voltage is generated by
the internal voltage regulator.
NOTE
No load allowed except for bypass capacitors.
1.2.4.7 VREGEN — On--Chip Voltage Regulator Enable
Enables the internal 5 V to 2.5 V voltage regulator. If this pin is tied low, VDD1,2 and VDDPLL must be
supplied externally.