[Solved] KEIL Run Error: \KEY.axf: Error: L6218E: Undefined symbol EXTI_ClearITPendingBit (referred from exit.o).

This is a problem when writing interrupt experiments. Generally, the path of exti. C file is not added

Step 1: click manage to add

Step 2: add the exti file in fwalb

Step 3 click add in files and find the exti. C file in the SRC file in fwlib

Add will work normally.