sync to data occurrence in the same cycle

Question

I am using Sync in the following way:

sync true (ports.ocp_cmd$ == 3'b010);

I want the simulator to go to the next command the same cycle the data in ocp_cmd is 010. currently the simulator automatically jumps 1 cycle and only then goes to the next specman command.

How can I change my command line so that no delay is created (so that I will be able to raise the ack signal in the same cycle if desired)

sync true (ports.ocp_cmd$ == 3'b010); ports.ocp_read_accept$ = 1 ; — tom, Jul 30 '15 at 07:11
currently, the ocp_read_accept receives a value of 1 only 1 cycle after the occurrence of ocp_cmd == 010. But I want the accept to rise in the same cycle. — tom, Jul 30 '15 at 07:13

score 0 · Answer 1 · answered Jul 30 '15 at 17:57

Since the sync true statement must reside in a time consuming method. Compare when the sampling event - for the time consuming method - occurs relative to the change in ocp_cmd becoming 3'b010. It could be that you must modify your sampling event.

score 0 · Answer 2 · answered Jul 31 '15 at 16:48

I guess what you mean that you sample ocp_cmd at the rising edge of the clock and this means you are raising ocp_read starting with that clock, which means the two signals will have a 1 cycle delay between each other.

If you know ocp_cmd doesn't glitch, you can change your sync to sync true (ports.ocp_cmd$ == 3'b010) @sim.

This isn't proper practice when working with synchronous signals. You'd be better of monitoring the cause of ocp_cmd going to 010 and relying on that.

sync to data occurrence in the same cycle

2 Answers2