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Chapter 8 S12 Clock, Reset and Power Management Unit (S12CPMU_UHV_V6)
MC9S12ZVM Family Reference Manual Rev. 1.3
Freescale Semiconductor
291
8.3.2.25
Voltage Regulator Control Register (CPMUVREGCTL)
The CPMUVREGCTL allows to enable or disable certain parts of the voltage regulator.This register must
be configured after system startup.
Read: Anytime
Write: Once in normal modes, anytime in special modes
Module Base + 0x001D
7
6
5
4
3
2
1
0
R
0
0
0
0
0
EXTCON
EXTXON
INTXON
W
Reset
0
0
0
0
0
1
1
1
= Unimplemented or Reserved
Figure 8-34. Voltage Regulator Control Register (CPMUVREGCTL)
Table 8-29. Effects of writing the EXTXON and INTXON bits
value of
EXTXON
to be written
value of
INTXON
to be written
Write Access
0
0
blocked, no effect
0
1
legal access
1
0
legal access
1
1
blocked, no effect
Table 8-30. CPMUVREGCTL Field Descriptions
Field
Description
2
EXTCON
External voltage regulator Enable Bit for VDDC domain — Should be disabled after system startup if VDDC
domain is not used.
0 VDDC domain disabled
1 VDDC domain enabled
1
EXTXON
External voltage regulator Enable Bit for VDDX domain — Should be set to 1 if external BJT is present on
the PCB, cleared otherwise.
0 VDDX control loop does not use external BJT
1 VDDX control loop uses external BJT
0
INTXON
Internal voltage regulator Enable Bit for VDDX domain— Should be set to 1 if no external BJT is present on
the PCB, cleared otherwise.
0 VDDX control loop does not use internal power transistor
1 VDDX control loop uses internal power transistor