Question

Protel DXP自动布线时报错 Error : Pad U12-10 Appears to be unroutable. Violation against Rule - Clea

Error : Pad U12-10 Appears to be unroutable. Violation against Rule - Clearance Clearance Constraint (Gap=0.254mm) (All),(All) Detected.
Error : Pad U12-14 Appears to be unroutable. Violation against Rule - Clearance Clearance Constraint (Gap=0.254mm) (All),(All) Detected.
Error : Pad U7-1 Appears to be unroutable. Violation against Rule - Clearance Clearance Constraint (Gap=0.254mm) (All),(All) Detected.
Error : Pad U6-17 Appears to be unroutable. Violation against Rule - Clearance Clearance Constraint (Gap=0.254mm) (All),(All) Detected.
Error : Pad U4-20 Appears to be unroutable. Violation against Rule - Clearance Clearance Constraint (Gap=0.254mm) (All),(All) Detected.
Error : Pad U4-18 Appears to be unroutable. Violation against Rule - Clearance Clearance Constraint (Gap=0.254mm) (All),(All) Detected.
Error : Pad U4-14 Appears to be unroutable. Violation against Rule - Clearance Clearance Constraint (Gap=0.254mm) (All),(All) Detected.
Error : Pad U3-13 Appears to be unroutable. Violation against Rule - Clearance Clearance Constraint (Gap=0.254mm) (All),(All) Detected.
Error : Pad U2-9 Appears to be unroutable. Violation
改小了最小布线宽度还是不行，改了SMDNeckDown也不行，到底应该怎么改规则？

Answer 1

这个错误提示是Clearance（间距，间隔）超出Rule限制，你把Clearance规则改小，就可以进行自动布线等工作了。
但是我认为间距规则的设置一般要尽量宽些。
尤其是有些特殊的信号线，可能要间距更大些
有些电源线，一般电流较大，走线宽度应该大些

Answer 2

应该改最小间距，上面已经提示的很明显了，是因为最小间距规则冲突导致的无法布线，当然还有最小线宽的问题，最小线宽最好选用最大不超过焊盘宽度的线宽为宜