vivado怎么解决Unconstrained Logical Port [DRC NSTD-1] [DRC UCIO-1]错误

1.问题描述

   很多工程有些logic port,我们不想对它进行管脚约束，但是不约束在生成bit文件时会产生类似下面的错误

[DRC UCIO-1] Unconstrained Logical Port: 10 out of 28 logical ports have no user assigned specific location constraint (LOC). This may cause I/O contention or incompatibility with the board power or connectivity affecting performance, signal integrity or in extreme cases cause damage to the device or the components to which it is connected. To correct this violation, specify all pin locations. This design will fail to generate a bitstream unless all logical ports have a user specified site LOC constraint defined.  To allow bitstream creation with unspecified pin locations (not recommended), use this command: set_property SEVERITY {Warning} [get_drc_checks UCIO-1].  NOTE: When using the Vivado Runs infrastructure (e.g. launch_runs Tcl command), add this command to a .tcl file and add that file as a pre-hook for write_bitstream step for the implementation run.  Problem ports: led0[7:0], sim_train_en, and sys_rst.

[DRC NSTD-1] Unspecified I/O Standard: 10 out of 28 logical ports use I/O standard (IOSTANDARD) value 'DEFAULT', instead of a user assigned specific value. This may cause I/O contention or incompatibility with the board power or connectivity affecting performance, signal integrity or in extreme cases cause damage to the device or the components to which it is connected. To correct this violation, specify all I/O standards. This design will fail to generate a bitstream unless all logical ports have a user specified I/O standard value defined. To allow bitstream creation with unspecified I/O standard values (not recommended), use this command: set_property SEVERITY {Warning} [get_drc_checks NSTD-1].  NOTE: When using the Vivado Runs infrastructure (e.g. launch_runs Tcl command), add this command to a .tcl file and add that file as a pre-hook for write_bitstream step for the implementation run. Problem ports: led0[7:0], sim_train_en, and sys_rst.

2.怎么解决

根据上面的错误提示可以知道使用

set_property SEVERITY {Warning} [get_drc_checks NSTD-1]
set_property SEVERITY {Warning} [get_drc_checks UCIO-1]
set_property SEVERITY {Warning} [get_drc_checks RTSTAT-1]  

将上述命令添加一个tcl文件中，然后按照下面方式设置