How can I simulate pull-up and pull-down resistors in the ModelSim® software? - How can I simulate pull-up and pull-down resistors in the ModelSim® software? Description You can use two variable types, tri0 and tri1 , to simulate pull-up and pull-down resistors when connecting the module's output/bidirectional net signals. These two variable types simulate the net signals being pulled-down or pulled-up when this signal is not driven. An example declaration is as follows: module pullup_tb; reg a, b, d, clk; //these are inputs tri1 c,q; //these are outputs; instead of: wire c, q; weak_pullupmodelsim my_wkpu( .a(a), .b(b), .c(c), .d(d), .clk(clk), .q(q) ); Simulating the above example will pull-up net signals c and q to simulate the way these signals would act on the board. Custom Fields values: ['novalue'] Troubleshooting novalue False ['novalue'] ['novalue'] novalue novalue ['Programmable Logic Devices'] ['novalue'] ['novalue'] ['novalue']