7275 - MachXO2/MachXO3: Why is the output of the I2C bus of EFB for MachXO2 and MachXO3 gives Hi-Z output at simulation?

7275 - MachXO2/MachXO3: Why is the output of the I2C bus of EFB for MachXO2 and MachXO3 gives Hi-Z output at simulation?

Description: 
When simulating MachXO2/MachXO3 I2C bus, the output in the simulation is only Hi-Z. 

Solution:

The I2C bus of EFB needs a pull up at the test bench in order for proper switching behavior. See below for example implementation at Verilog:

assign (pull1,strong0) i2c1_scl=1'b1;
assign (pull1,strong0) i2c1_sda=1'b1;

See below for example output: