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UM10850
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© NXP B.V. 2016. All rights reserved.
User manual
Rev. 2.4 — 13 September 2016
69 of 464
NXP Semiconductors
UM10850
Chapter 4: LPC5410x System configuration (SYSCON)
4.6.3 Brown-out detection
The part includes up to four 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 STARTER0 register and in the NVIC, the BOD
interrupt can wake up the chip from reduced power modes, not including deep
power-down.
If the BOD reset is enabled, the forced BOD reset can wake-up the chip from reduced
power modes, not including deep power-down.
On the LPC5410x, the BOD is enabled by default after power-up. At this time the BOD is
set to the lowest value (1.5v) with no factory trimming applied. In the BOD block the
interrupt portion is turned off and only the reset portion is on. After POR/BOD resets, the
BootROM takes over and applies the factory BOD trim value so that the trip points
become accurate. See the LPC5410x data sheet for BOD interrupt/reset voltage levels in
the BOD static characteristics.
4.6.4 PLL functional description
The PLL is typically used to create a frequency that is higher than other on-chip clock
sources, and used to operate the CPU and/or other on-chip functions. It may also be used
to obtain a specific clock that is otherwise not available. For example, a clock with a
frequency of any integer MHz (e.g. the 12 MHz IRC) can be divided down to 1 MHz, then
multiplied up to any other integer MHz (e.g. 13, 14, 15, etc.).
Fig 5.
PLL block diagram showing typical operation
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