EEC 116 - Irsim Notes and Tips

irsim version 9.7.117 (first installed Oct 2023) has a few minor differences with past versions.

• The "w" command appears to be no longer supported.

• Only the "Gnd" node is automatically set to low. So for example if your power and ground nodes are labeled "Vdd" and "GND" in your magic layout, you should begin your irsim simulation with the following two lines:
  h Vdd
  l GND

• irsim is now installed in /usr/local/bin/ instead of /bin/ however the DOT2.cshrc file takes care of the changes.

After working through the irsim tutorials and documentation, you may find some of the tips below helpful in making you more productive.

• Never use global labels (labels ending in "!"). Even in subcells as they can confuse your simulation.

• Example irsim cmd files: 1clk.cmd, example.cmd, assume your clock signal is called "clock".

• Although less flexible, the "c" command may also be helpful to generate a clock.

• Assuming a system with positive-edge-triggered flip-flops, always change the inputs on the falling edge of clock in your irsim cmd file.

2018/11/29  Written (BB)
2023/10/23  Some changes for the new version 9.7.117 installed Oct 2023.