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MPC5668EVB Users Manual Rev 0.1 May 2009
MPC5668EVBUM/D Page 8 of 29
3.1.5.1 Changing VDDE[1..4] Voltage
Before changing the VDDEx voltage from the default 5.0V setting, you need to ensure that this will not impact
any of the EVB peripherals that you are using. The table below details what EVB peripherals are tied to a
particular VDDEx grouping and also the MCU pin operating voltage suitable for that peripheral.
Table 3-3 VDDE[1..3] Pad Groupings
Item Port Pins VDDE Group Required Pad Voltage
Ethernet Port G and H VDDE3 3.3V
CANA and CANB Port D VDDE2 5.0V or 3.3V
SCI A and B Port D VDDE2 5.0V or 3.3v
LIN C and D Port E VDDE2 5.0V or 3.3v
FlexRay Port K VDDE2 5.0V or 3.3V
JTAG Dedicated JTAG VDDE2 5.0V or 3.3V
Nexus Custom Domain VDDENEX 3.3V
3.1.6 Regulator Power Domains
Before disabling any of the EVB regulators, it is worthwhile considering if any of the EVB components or
peripherals you require will be affected. Table 3-4 details a list of the various EVB components and
peripherals powered by the regulators.
Table 3-4 Power Supply Distribution
Regulator Used On
2.5V
(Switcher)
MCU VDDEMLB pins
MLB INIC
1.5V Power section of Prototype area
3.3V
(Switcher)
MCU VDD33 and VDDSYN pins (ONLY use when on-chip MCU regulator is
disabled)
MCU VDDEx pins (when run in 3.3v mode)
Oscillator Module (U20)
MLB INIC
RS-232 Transceiver (VDDE2 dependant)
LIN transceiver (VDDE2 dependant)
I/O supply for Flexray interface when VIO is 3.3V
LVI circuitry
3.3V Power section of Prototype area
5.0V
(Switcher)
MCU VDDEx (5v mode), VPP and VDDR pins
LVI circuit main power (affecting Reset Switch)
Reset-In / Reset-Out logic
Reset configuration circuitry
User LED’s and Switches.
RS-232 Transceiver (VDDE2 dependant)
LIN transceiver (VDDE2 dependant)
CAN transceivers
FlexRay transceivers
5.0V Power section of Prototype area
JTAG and Nexus connectors
5.0V
(Linear)
MCU VDDA pin
LVI circuit monitor