Unrouted nets:4 net(s) are unrouted .The problem bus(es) and/or net(s) are............
答(dá)：出(chū)現(xiàn)这(zhè)个(gè)錯誤的(de)原因(yīn)一(yī)般是(shì)：xdc文(wén)件(jiàn)中(zhōng)的(de)約束(shù)不(bù)正(zhèng)确或(huò)者(zhě)沖突，解(jiě)決方(fāng)法如(rú)下(xià)
1、根(gēn)據(jù)实際使用(yòng)情(qíng)況重(zhòng)新進(jìn)行約束(shù)
2、在(zài)将IOB屬性(xìng)更(gèng)改为(wèi)TRUE