Create a 500ns pulse through Arduino Uno/Mega?

Thank you DrDiettrich, just checked that, still doesn't work though. :confused:

I'm not sure what you mean. After the programming pulse you have to wait for the current command to complete, not a specific time before the next pulse.

I don't have access to a scope at all times. Did you test this code with one?

Yes. Unfortunately, it's a rather old scope, so it's tough to get pictures onto the web...