管脚中的：special function 中的那些描述的意思 function, special, 意思, 描述

icesword

我用NIOSII做了一个小系统，用8位的PIO来驱动一个七段数码管，将管脚绑定后编译出现了如下问题：Info: Fitter is performing an Auto Fit compilation -- Fitter effort may be decreased to reduce compilation time
Info: Device migration not selected. If you intend to use device migration later, you may need to change the pin assignments as they may be incompatible with other devices.
        Info: Device EP1C12Q240C8 is compatible
Error: Can't place node ~nCSO~ in location PAD_20 because location already occupied by node display[2]
Error: Can't place node ~ASDO~ in location PAD_30 because location already occupied by node display[3]
Info: No exact pin location assignment(s) for 4 pins of 27 total pins
        Info: Pin altera_reserved_tdo not assigned to an exact location on the device
        Info: Pin altera_reserved_tms not assigned to an exact location on the device
        Info: Pin altera_reserved_tck not assigned to an exact location on the device
        Info: Pin altera_reserved_tdi not assigned to an exact location on the device
Error: Can't fit design in device
Error: Quartus II Fitter was unsuccessful. 3 errors, 0 warnings
        Error: Processing ended: Thu Apr 21 08:28:33 2005
        Error: Elapsed time: 00:00:02
Error: Quartus II Full Compilation was unsuccessful. 3 errors, 81 warnings
我看了一下确实所帮定管脚的特殊功能是：ncso和asdo。请问SPECIAL FUNTION中的那些描述分别代表什么意思啊。我的这个问题如何解决啊。因为是开发板，无法改变管脚的位置。[em18]