Modelsim:Error: (vsim-3009) [TSCALE] - Module 'my_button' does not have a timeunit/timeprecision specification in effect, but other modules do.

故障现象：

Error: (vsim-3009) [TSCALE] - Module 'my_button' does not have a timeunit/timeprecision specification in effect, but other modules do.

解决办法：

在源程序中添加时间精度，如：`timescale 1 ps/ 1 ps

或者可以使用在vsim指令后加-supress 3009屏蔽该告警。