This knowledge base is intended to answer technical questions, in particular topics related to troubleshooting and support.

Make sure your key is for the product you are using and that you have the most recent version. It is important to enter the key exactly as it appears in the email, with no extra spaces before or after it. To avoid typos, copy/paste the key directly from the registration notice.

You need to regenerate a new license file for every new release of LogicSim. This is covered under maintenance services, which is 1-year free when you first purchase LogicSim. You can get a new activation key at our maintenance services page. Just enter your purchase time email address and an activation key will be emailed to you immediately.

Yes, we can. Just drop us an email and we will help retrieve your software activation key immediately.

The reason this happens is because LogicSim generates a license file based on what you enter. But then the simulator engine does the license checking, and found it invalid, so does not continue. Two ways to solve this problem:

1. Register and get a valid license key, and then regenerate the license file.
2. Manually delete the license file "lsim.license" from your LogicSim installation directory, e.g. "C:\Program Files\Zeemz\LogicSim 1.0\lsim.license" and continue evaluation.

Our system will automatically send out the software activation key within 24 hours upon payment. But in many cases, our automated email messages may end up in our customers' spam mailbox. If you do not receive your software activation key after 24 hours upon payment, please check your spam mailbox, it might have ended up there.

There could be several reasons for this:

1. Your VCD file attribute is set to read-only, hence you need to unset it to writable.
2. The path you specify doesn't exist, e.g. "mypath/myfile.vcd", whereas "mypath" doesn't exist. LogicSim won't be able to create a path for you, as it is machine dependent. However, if you specify just "myfile.vcd" and it doesn't exist, then LogicSim will create the file automatically. This is due the limitation in the C++ standard library, so in order to solve this problem, you either create the path by yourself, or specify just the file name.

This error is common when simulating Xilinx gate-level netlists. The reason is due to Xilinx ISE generates a global JTAG module which is not instantiated by the top-level module. Hence, LogicSim is not able to resolve "glbl.GTS" when it is referred to in Xilinx Verilog primitives. In order to fix this, you need to include the following line of code into the top-level module:

module top_module;

...

glbl g(); // <--- insert this

...

endmodule