Hi Richard,
I understand that you are trying to use an event guard on a loop in a Stateflow chart with super step semantics enabled, and you want the chart to “wait” at the event guard until the next clock tick/event. However, with super step semantics turned on, the model does not stop at the event guard as expected.
When running a similar setup, I observed that this happens because super step semantics executes transitions repeatedly within the same simulation step until the chart reaches a stable state. If your event is still considered active during that step, the guarded transition will immediately fire again instead of waiting.
To resolve this, you should introduce a delay or store the event in a local flag so the transition only becomes valid in the next simulation tick. Kindly refer to the following example approach using a local flag:
Step 1: Create a local data variable in the chart, for example:
eventFlag
with an initial value of “false”.
Step 2: In the state that receives the event, add an “on eventName:” action:
eventFlag = true;
Step 3: Now, guard your loop transition using:
[eventFlag]
Step 4: After processing the event in the target state, reset:
eventFlag = false;
Alternatively, if you prefer not to use a flag, you can enforce a simulation step delay in the transition guard (temporal logic method):
[after(0, tick) && eventName]
This ensures the transition will only be valid in the next tick, even with super step semantics enabled.
For further reference on “super step semantics” and “temporal logic” operators, kindly refer to the documentation below:
