target processor: not responding

I have the same problem, with the low-cost Cyclone development kit, with the ep1c12q240.

It is also my first experience with the Altera development tools.

The first few compilations the processor worked ok, but all subsequent compilations generate processors that apparently are dead (I kept the .sof file, and it still works - so it is not a hardware failure).

I added a timer with the timeout pulse enabled, followed by a flip-flop and a led. It should blink if the processor is minimally working. In the first compilations the led blik as expected, and the "hello world" works ok. In later compilations the processor seems dead, and I get the same message as you.

I suggest you do the same; if the led does not blink, we should have the same problem.

I am using Quartus 4.2 sp1, build 178, and Nios 2.1.1.