
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
56 of 487
NXP Semiconductors
UM10800
Chapter 5: LPC82x System configuration (SYSCON)
5.7.3 Brown-out detection
The brown-out detection circuit includes up to three levels for monitoring the voltage on
the V
DD
pin. If this voltage falls below one of the selected levels, the BOD asserts an
interrupt signal to the NVIC or issues a reset, depending on the value of the BODRSTENA
bit in the BOD control register (
).
The interrupt signal can be enabled for interrupt in the Interrupt Enable Register in the
NVIC (see
) in order to cause a CPU interrupt; if not, software can monitor the
signal by reading a dedicated status register.
If the BOD interrupt is enabled in the STARTERP1 register (see
) and in the
NVIC, the BOD interrupt can wake up the chip from Deep-sleep and power-down mode.
If the BOD reset is enabled, the forced BOD reset can wake up the chip from Deep-sleep
or Power-down mode.
5.7.4 System PLL functional description
The LPC82X uses the system PLL to create the clocks for the core and peripherals.
Fig 6.
Start-up timing
valid threshold
= 1.8V
processor status
V
DD
IRC status
internal reset
GND
80
µ
s
101
µ
s
boot time
user code
boot code
execution
finishes;
user code starts
IRC
starts
supply ramp-up
time
55
µ
s