GD32F20x User Manual
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6.4.
External interrupt and event (EXTI) block diagram
Figure 6-1. Block diagram of EXTI
EXTI Line0~19
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 20 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 4 lines from internal
modules (including LVD, RTC Alarm, USBFS Wakeup, Ethernet Wakeup). All GPIO pins can
be selected as an EXTI trigger source by configuring AFIO_EXTISSx registers in GPIO
module (please refer to
GPIO and AFIO
section for detail).
EXTI can provide not only interrupts but also event signals to the processor. The Cortex-M3
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.
Summary of Contents for GD32F20 Series
Page 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Page 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Page 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Page 385: ...GD32F20x User Manual 385 ...
Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...