I want to design a counter when each time my input transition from 0 to 1 and after 5 such transitions within 5 seconds my output goes to 1

I want to design a counter when each time my input transition from 0 to 1 and after 5 such transitions within 5 seconds my output goes to 1 but we should not count the time when the state is at 1 or 0

Can you help me with this logic either in simulink or using stateflow or both mixed

Answer 1

[Ayush]

Hey Vignesh,

I understand that you are trying to design a counter that increments each time your input transitions from 0 to 1. If there are 5 such transitions within a 5-second window, the output should be set to 1. The timer should only count the time when the input is neither 0 nor 1 continuously.

Here's a workaround using Simulink and stateflow:

Simulink Setup

1. Input Signal: Use a Pulse Generator or Constant block to simulate the input signal.
2. Stateflow Chart: Create a Stateflow chart to handle transition detection, counting, and timing logic.

Stateflow Chart Design

States:

• Idle: Waiting for the first transition.
• Counting: Counting transitions within 5 seconds.
• Output: Setting the output to 1 if the condition is met.

Transitions:

• Idle to Counting: On detecting the first 0 to 1 transition.
• Counting to Idle: If 5 seconds pass without 5 transitions.
• Counting to Output: If 5 transitions are detected within 5 seconds.

Stateflow chart

state Idle {
    on entry: count = 0; timer = 0;
    if (input == 1) {
        transition to Counting;
    }
}

state Counting {
    on entry: timer = 0;
    during: timer = timer + dt;
    if (input == 1 && prev_input == 0) {
        count = count + 1;
    }
    if (count >= 5) {
        transition to Output;
    }
    if (timer >= 5) {
        transition to Idle;
    }
}

state Output {
    on entry: output = 1;
    on exit: output = 0;
    transition to Idle;
}

Simulink Integration

1. Input: Connect the input signal to the Stateflow chart.
2. Output: Connect the output of the Stateflow chart to an Outport block.

This is how the complete flow will look like:

[Input Signal] --> [Stateflow Chart] --> [Output Signal]

Please refer to the following MathWorks documentation link(s):

1. https://www.mathworks.com/help/stateflow/ug/detecting-edges-in-signals.html
2. https://www.mathworks.com/help/stateflow/ug/modeling-a-simple-system-with-stateflow.html
3. https://www.mathworks.com/help/stateflow/ug/using-the-after-operator.html (for using timers in Stateflow)

Hope this helps

Regards