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Rev. 1.00
180 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
11 External Interrupt/Event Controller (EXTI)
EVWUPIEN
SLEEPING
(NVIC)
EXTI Wakeup Interrupt Service Routine Management
EXTInWFL
EXTIn
LVD_WAKEUP
WUPF
PWRCU
EXTInWEN
High/Low
level detector
EXTInWPOL
1
0
16
16
16
16
16
16
WAKEUP1
16
16
16
CMP_WAKEUP
CMP
(Note)
RTC_WAKEUP
16
EVWUP interrupt
(NVIC)
BODEN
LVDEWEN
WUP0EN
CMPWPEN
16
16
16
EXTInEN
EXTIn interrupt
(NVIC)
BODRIS
LVDIWEN
CMPRIEN
LVD_BOD interrupt
(NVIC)
RTC interrupt
(NVIC)
OV / CM
CSECIEN
RTC
OV / CM /
CSECWEN
BOD_WAKEUP
CMP interrupt
(NVIC)
WAKEUP0
WUP1EN
Note: CMP is only available for the HT32F54243/HT32F54253 devices.
Figure 28. EXTI Wakeup Interrupt Service Routine Management
Interrupt and Debounce
The application software can set the DBnEN bit in the EXTIn Interrupt Configuration Register
EXTICFGRn (n = 0 ~ 15) to enable the corresponding pin debounce function and configure the
DBnCNT field in the EXTICFGRn register so as to select an appropriate debounce time for specific
applications. The interrupt signal will however be delayed due to the debounce function. When
the device is woken up from the power saving mode by an external interrupt, an interrupt request
will be generated by the EXTI wakeup flag. After the device has been woken up and the clock has
recovered, the EXTI wakeup flag that was triggered by the EXTI line must be read and then cleared
by application software. The accompanying diagram shows the relationship between the EXTI
input signal and the EXTI interrupt/event request signal.
EXTIn
pin input
EXTIn
interrupt
request
Debounce
time delay
Low pulse is
shorter than
debounce time
Figure 29. EXTI Interrupt Debounce Function