UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
155 of 1269
NXP Semiconductors
UM10503
Chapter 13: LPC43xx Reset Generation Unit (RGU)
The second level of granularity is monitored by one individual register for each reset
output (RESET_EXT_STATUSn) in which the detailed reset cause is indicated, that is
whether or not any of the possible inputs to each reset generator are activated. The
following lists all inputs, but note that only a subset of inputs are connected to each reset
generator:
•
External reset (from external reset pin)
•
CORE_RST output
•
PERIPH_RST output
•
MASTER_RST output
•
BOD reset signal
•
WWDT time-out signal
13.3.1 Reset hierarchy
The hierarchy is as follows (see
1. External reset, BOD reset signal, WWDT time-out, and reset signal from the PMU
2. CORE_RST (inputs are the external reset pin, BOD reset, and the WWDT time-out
reset); resets the whole chip including the WWDT and the configuration register block
CREG.
3. PERIPH_RST (input is the CORE_RST); resets all APB peripherals and the ARM
core, but not the WWDT and the CREG block.
4. MASTER_RST (input is the PERIPH_RST); resets the ARM Cortex-M4 core and the
AHB peripherals (DMA, USB0/1, LCD, SDIO, EMC).
Table 112. Reset priority
Priority Reset input
WWDT
CREG/
RTC/
Event
router
ABP
peripherals
Cortex-
M4 Core
AHB
peripherals
RGU
EMC GPIO SRAM
controllers
1
External reset pin,
BOD, WWDT
yes
yes
yes
yes
yes
yes
yes
yes
yes
2
CORE_RST
yes
yes
yes
yes
yes
yes
yes
yes
yes
3
PERIPH_RST
no
no
yes
yes
yes
yes
yes
yes yes
4
MASTER_RST
no
no
no
yes
yes
yes
yes
yes
yes