Hi - > >How would you prefer to cause interrupts? > > I want to simulate a periodic interrupt( specifically, > I want to be able to count the heart beats [...] OK. > Hence, I guess a script or a program would be > a suitable way to do it. That's possible, but not necessary for this context. Probably the easiest thing to do is to use one of the sid scheduler objects to supply the periodic interrupt. You would have to decide whether you would like these interrupts based on the progression of host (real) time, versus target (simulated) time. Then, you'd pick a suitable time interval, in milliseconds or clock ticks respectively. Then you'd arrange to get the chosen scheduler to send out a ping at the chosen interval to the appropriate interrupt input pin. This latter bit is most easily done by emitting and editing the sid configuration file that otherwise models your desired system. > Presently,I am reading through the SID user manual. Is > there any other documentation, which can be helpful? The other two families of documentation that you may find helpful consist of a guide on developing sid components and the set of individual component reference pages. These may all be found on the sid project web page. - FChE