Data Sheet

NUC123
May 3, 2017 Page 34 of 99 Rev.2.04
NUC123 SERIES DATASHEET
Figure 6-4 Power-on Reset (POR) Waveform
Low Voltage Reset (LVR) 6.2.2.3
If the Low Voltage Reset function is enabled by setting the Low Voltage Reset Enable Bit
LVR_EN (BODCR[7]) to 1, after 100us 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 (16*HCLK cycles),
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. The RSTS_RESET (RSTSRC[1]) will
be set to 1 if the previous reset source is nRESET reset. Figure 6-5 shows the Low Voltage Reset
waveform.
AV
DD
V
LVR
Low Voltage Reset
T
1
(<De-glitch time)
T
2
(=De-glitch time)
T
3
(=De-glitch time)
LVR_EN
100 us
Delay for LVR stable
Figure 6-5 Low Voltage Reset Waveform
Brown-out Detector Reset (BOD Reset) 6.2.2.4
If the Brown-out Detector (BOD) function is enabled by setting the Brown-out Detector Enable Bit
BOD_EN (BODCR[0]), Brown-Out Detector function will detect AV
DD
during system operation.
When the AV
DD
voltage is lower than V
BOD
which is decided by BOD_EN (BODCR[0]) and
BOD_VL (BODCR[2:1]) and the state keeps longer than De-glitch time (Max(20*HCLK cycles,
1*LIRC cycle)), chip will be reset. The BOD reset will control the chip in reset state until the AV
DD
voltage rises above V
BOD
and the state keeps longer than De-glitch time. The default value of
BOD_EN, BOD_VL and BOD_RSTEN is set by flash controller user configuration register
CBODEN (CONFIG0[23]), CBOV1-0 (CONFIG0[22:21]) and CBORST (CONFIG0[20])
respectively. User can determine the initial BOD setting by setting the CONFIG0 register. Figure
6-6 shows the Brown-Out Detector waveform.