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GD32L23x User Manual
131
6.4.
External interrupt and event (EXTI) block diagram
Figure 6-1. Block diagram of EXTI
EXTI Line0~29
Edge
detector
Polarity
Control
Software
Trigger
Interrupt Mask
Control
Event
Generate
Event Mask
Control
To NVIC
To Wakeup Unit
6.5.
External interrupt and Event function overview
The EXTI contains up to 30 independent edge detectors and generates interrupts request or
event to the processer. The EXTI has three trigger types: rising edge, falling edge and both
edges. Each edge detector in the EXTI can be configured and masked independently.
The EXTI trigger source includes 16 external lines from GPIO
pins and 14 lines from
internal
modules
(including LVD, USB, RTC, I2C USART, CMP, LPUART and LPTIMER).
All GPIO
pins can be selected as an EXTI trigger source by configuring SYSCFG_EXTISSx registers
in SYSCFG module (please refer to
System configuration registers
EXTI can provide not only interrupts but also event signals to the processor. The Cortex
®
-
M23 processor fully implements the Wait For Interrupt (WFI), Wait For Event (WFE) and the
Send Event (SEV) instructions. The Wake-up Interrupt Controller (WIC) enables the
processor and NVIC to be put into a very low-power sleep mode leaving the WIC to identify
and prioritize interrupts and event. EXTI can be used to wake up processor and the whole
system when some expected event occurs, such as a special GPIO pin toggling or RTC alarm.