MPC563XM Reference Manual, Rev. 1
1340
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
30.4
Functional Description
The power management controller provides the base current for an external ballast transistor to generate
the 1.2V supply. It also contains a 3.3V regulator and several POR / LVI voltage monitors for system
supervision.
A 5V loose tolerance detection circuit (POR 5V) is used to determine if the supply voltage VDDREG is
high enough to guarantee the startup of bandgap voltage reference (at 2.7V). As a consequence 5V and 3V
LVI’s can safely startup with reliable output value. The device is kept in reset until 5V LVI has been
cleared, allowing for correct 3.3V regulator, 1.2V regulator and 1.2V LVI startup
Internal 3.3V and 1.2V POR are included to provide minimum low voltage reset capability.
The voltage regulators can be disabled to support the connection of external power supplies to the 3.3V
and 1.2V pins. For the 1.2V supply this is most easily achieved by omitting the bypass transistor. For the
3.3V supply it is necessary to remove the 5V supply of the regulator (connect VDDREG to ground). If the
regulator is disabled, then the LVI on the VDDEH, VDDREG, 1.2V and 3.3V supplies are also disabled.
Therefore, when using external power supplies, the user has to provide external LVI monitoring.
As POR’s are powered by VHH their value is reliable also when VDDREG is grounded, as long as
VDDEH or VDD3p3 are at the correct voltage.
30.4.1
Bandgap
The bandgap voltage of the PMC is capable of generating a reference voltage of 1.219V that varies by +/-
4% before calibration and +/-1% after calibration over temperature and lifetime. It is used as reference to
generate all supply voltages, for this reason it is powered directly out of the 5V domain to avoid startup
racing conditions. Supply voltage range is from 4.5 to 5.5V. The bandgap shall work with decreased
performance down to 4.0V supply.
27
LVI3F
3.3V LVI flag. This read-only bit is the LVI interrupt flag associated with the 3.3V supply. It is asserted
when the 3.3V supply falls below the corresponding LVI threshold, and can be cleared by the CPU by
writing 1 to the LVI3C bit. If the LVI3E bit is also asserted, an LVI interrupt is sent to the CPU. If LVI3R
is also asserted, a system reset will be generated, which will clear the LVI3F flag and negate the interrupt
request.
0 No occurrence.
1 LVI occurrence detected on the 3.3V supply.
28
LVI1F
1.2V LVI flag. This read-only bit is the LVI interrupt flag associated with the 1.2V supply. It is asserted
when the 1.2V supply falls below the corresponding LVI threshold, and can be cleared by the CPU by
writing 1 to the LVI1C bit. If the LVI1E bit is also asserted, an LVI interrupt is sent to the CPU. If LVI1R
is also asserted, a system reset will be generated, which will clear the LVI1F flag and negate the interrupt
request.
0 No occurrence.
1 LVI occurrence detected on the 1.2V supply.
29-31
Reserved.
Table 30-5. SR Field Descriptions (continued)
Field
Description