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Rev. 1.00
115 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
6 Clock Control Unit (CKCU)
7 Reset Control Unit (RSTCU)
7
7
Reset Control Unit (RSTCU)
Introduction
The Reset Control Unit, RSTCU, has three kinds of reset, the power-on reset, system reset and
APB unit reset. The power-on reset, known as a cold reset, resets the full system during a power
up. A system reset resets the processor core and peripheral IP components with the exception of
the debug port controller. The resets can be triggered by an external signal, internal events and the
reset generators. More information about these resets will be described in the following section.
V
CORE
Power POR
Filter
Filter
Delay
PORRESETn
WDT_RSTn
SYSRESETREQ
----
nRST
V
CORE
V
CORE
_POR
HRESETn
Reset
Generator
WDTRST
Reset
Generator
URnRST
WDT Reset
UARTn Reset
V
DD
Domain
POR
Filter
PORB
V
DD
PWCURST
RTC/PWRCU
Reset
Brown-Out
Detector
RESET
Filter
V
DD
BODRST
Cortex
®
-M0+
RSTCU
NVIC
SYSRESETn
SYSRESETREQ
HRESETn
CORERESTn
CM0+ Core
System Components
(BusMatrix, PMU)
System Debug
Components
SYSRESETREQ
PORRESETn
Figure 20. RSTCU Block Diagram
Functional Descriptions
Power-On Reset
The Power-on reset, POR, is generated by either an external reset or the internal reset generator.
Both types have an internal filter to prevent glitches from causing erroneous reset operations. By
referring to Figure 21, the V
CORE
_POR active low signal will be de-asserted when the internal LDO
voltage regulator is ready to provide the V
CORE
power. In addition to the V
CORE
_POR signal, the
Power Control Unit, PWRCU, will assert the BODF signal as a Power-Down Reset, PDR, when the
BODEN bit in the LVDCSR register is set and the brown-out event occurs. For more details about
the PWRCU function, refer to the PWRCU chapter.