在Altera公司的Cyclone系列FPGA开发板上试验的按键中断程序，希望对那些学习中断开发的初学者有帮助。

pio_key.v是verilog编写的按键中断程序，对应四个按键，按其中任何一个键都可以发送一个中断；

keyint.c是Nios中编写的C程序，用于检测按键的中断，如果检测到中断，会检测是哪个按键按下，从而执行相应的程序！

-In Altera' s Cyclone series FPGA development board interrupt key test procedures, interruption of hope to those who study the development of help for beginners. verilog prepared pio_key.v button is interrupted procedures, corresponding to the four keys, in accordance with any one key can send an interrupt　keyint.c is prepared Nios of C procedures for detecting the interruption of keys, if the interruption is detected, will detect which button is depressed, thus the implementation of appropriate procedures!