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NUC126
Aug. 08, 2018
Page
76
of 943
Rev 1.03
NUC12
6 S
E
RI
E
S
T
E
CH
NI
CA
L R
E
F
E
RE
NCE
MA
NUA
L
Figure 6.2-2 nRESET Reset Waveform
6.2.2.2
Power-on Reset (POR)
The Power-on reset (POR) is used to generate a stable system reset signal and forces the system to
be reset when power-on to avoid unexpected behavior of MCU. When applying the power to MCU, the
POR module will detect the rising voltage and generate reset signal to system until the voltage is ready
for MCU operation. At POR reset, the PORF(SYS_RSTSTS[0]) will be set to 1 to indicate there is a
POR reset event. The PORF(SYS_RSTSTS[0]) bit can be cleared by writing 1 to it. Figure 6.2-3 shows
the power-on reset waveform.
V
DD
V
POR
Power-on
Reset
0.1V
Figure 6.2-3 Power-on Reset (POR) Waveform
6.2.2.3
Low Voltage Reset (LVR)
If the Low Voltage Reset function is enabled by setting the Low Voltage Reset Enable Bit LVREN
(SYS_BODCTL[7]) to 1, after 200us delay, LVR detection circuit will be stable and the LVR function
will be active. Then LVR function will detect AV
DD
during system operation. When the AV
DD
voltage is
lower than V
LVR
and the state keeps longer than De-glitch time set by LVRDGSEL
(SYS_BODCTL[14:12]), chip will be reset. The LVR reset will control the chip in reset state until the
AV
DD
voltage rises above V
LVR
and the state keeps longer than De-glitch time set by LVRDGSEL
(SYS_BODCTL[14:12]). The default setting of Low Voltage Reset is enabled without De-glitch
function. Figure 6.2-4 shows the Low Voltage Reset waveform.