Back to the original issue. There is no CLK_TCK function in the Apple Library for cc65.1)Is the CLK_TCK function necessary? 2)What is it used for? 3)Is it something which can be generated on a stock Apple ][?IIRC the Apple ][ generates its timing in an unusual and Woz way, without a crystal. Can CLK_TCK be generated in the same way?
Some good news for //e, 2c users! From a quick look in my //e Technical book (Apple/Addison-Wesley edition), there is an interrupt associated with Vertical Blanking (every 16ms) and OS interrupt support with ProDOS 8. The bad news: sorry for ][+ users but there are no built-in interrupt sources, altough a clever hardware hack exists to get vertical retrace interrupts (REF: Jim Sather, Understanding the Apple II, p.3-19 to 3-26). I guess Apple ][ users will have to provide their own timer interrupt services.
Cheers, Yves