Timer issue

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Summary:

Unexpected behaviour from a program with a timer

Timer issue

EmmanuelR 14 Jan 2020 23:19

Hi all!

I've got this program (code below) that isn't working as expected. There must me something wrong with the timer. Could you help me find out what?

Scenario:
The forward button is pressed, then the right button is pressed.

Actual result:
The right wheel start turning and keep turning indefinitely.

Expected result:
The right wheel starts turning and then stops after one second.

Program:

onevent button.center
    when button.center == 1 do
        motor.left.target = 0
        motor.right.target = 0
        call leds.top(32,0,0)
    end

onevent button.forward
    when button.forward == 1 do
        call leds.top(6,26,0)
        while not (button.center == 1) do
            if button.right == 1 then
                motor.right.target = -100
                timer.period[0] = 1000
                call leds.top(32,13,0)
            end
            if button.left == 1 then
                motor.right.target = 100
                timer.period[0] = 1000
                call leds.top(32,26,0)
            end
        end
    end

onevent timer0
    motor.left.target = 0
    motor.right.target = 0
    call leds.top(6,6,32)

Best regards,
Emmanuel

Re: Timer issue

riedo 21 Jan 2020 16:28

Hello,

The events (including the timer) happen when certain conditions are met, but they do not interrupt the code that is executed. A block of code is executed, and once it is done, the next block is executed if another event was triggered in the meantime.

In your code, you have a while loop which can only be exited if you press the center button. in this loop, pressing left or right sets the motor speed, and the length of the timer, but the timer event cannot be executed until you exit the while loop. It cannot interrupt.

Here is an example of code that behaves more like you intended I hope:

var state=0

onevent buttons
    when button.center == 1 do
        state=0
        timer.period[0]=0
        motor.left.target = 0
        motor.right.target = 0
        call leds.top(32,0,0)
    end

    when button.forward == 1 do
        call leds.top(6,26,0)
        state=1
    end

    if state==1 then  
    when button.right == 1 do
                motor.right.target = -100
                timer.period[0] = 1000
                call leds.top(32,13,0)
     end
            if button.left == 1 then
                motor.right.target = 100
                timer.period[0] = 1000
                call leds.top(32,26,0)
            end
      end  

onevent timer0
    motor.left.target = 0
    motor.right.target = 0
    timer.period[0]=0
    call leds.top(6,6,32)

Re: Timer issue

EmmanuelR 24 Jan 2020 21:39

Thanks a lot riedo !