Datasheet

255
32142D–06/2013
ATUC64/128/256L3/4U
The CTRL, HYST, and LEVEL fields in the BOD Control Register are loaded factory defined cal-
ibration values from flash fuses after a reset. If the Flash Calibration Done bit in the BOD Control
Register (BOD.FCD) is zero, the flash calibration will be redone after any reset, and the
BOD.FCD bit will be set before program execution starts in the CPU. If BOD.FCD is one, the
flash calibration is redone after any reset except for a BOD reset. The BOD.FCD bit is cleared
after a reset, except for a BOD reset. BOD.FCD is set when these fields have been updated after
a flash calibration. It is possible to override the values in the BOD.CTRL, BOD.HYST, and
BOD.LEVEL fields after reset by writing to the BOD Control Register. Please refer to the Fuse
Settings chapter for more details about BOD fuses and how to program the fuses.
Figure 14-6. BOD Block Diagram
14.5.6 Bandgap
Rev: 1.2.0.0
The flash memory, the BOD, and the Temperature Sensor need a stable voltage reference to
operate. This reference voltage is provided by an internal Bandgap voltage reference. This refer-
ence is automatically turned on at start-up and turned off during some sleep modes to save
power. The Bandgap reference is powered by the internal regulator supply voltage and will not
be powered during Shutdown sleep mode. Please refer to the Power Manager chapter for
details.
VDDCORE
POR18 BOD
SCIF
POWER MANAGER(PM)
INTC
Reset
Bod
Detected
Enable
B
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BOD
Level
Reset
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