在LAYOUT PCB的时候，为了保证信号完整性，往往需要在输出端串联一个33欧左右的阻抗匹配电阻，CYCLONE II的手册上提到，其I0口已经内置了OCT匹配电阻 I/O Driver Impedance Matching (RS) & Series Termination (RS) Cyclone II devices support driver impedance matching to the impedance of the transmission line, typically 25 or 50 Ω . When used with the output drivers, on-chip termination (OCT) sets the output driver impedance to 25 or 50 Ω by choosing the driver strength. Once matching impedance is selected, driver current can not be changed. Table 10–7 provides a list of output standards that support impedance matching. All I/O banks and I/O pins support impedance matching and series termination. Dedicated configuration pins and JTAG pins do not support impedance matching or series termination. 手册上找到这段，不过还是不明白具体在QUARTUS当中要如何设置相应的管脚呢？
