How many Interrupts per sec?

Archive
1

How many Interrupts do you think can be processed per second in managed code?

From my quick and dirty test i can only get 5 per second :frowning:

But in saying that i have my board driving PWM, reading Interrupt’s and writing to SPI… so still a good result :slight_smile:

2

In the past I have done tests on interrupt performance, and I have seen 1500-1700 interrupts per second. I did these tests on an EMX and USBizi.

In these tests, I had a PWM signal input to a InterruptPort, and did nothing in the interrupt handler, so I was measuring best case.

Five per second just sound way wrong. Of course, everything depends upon what you do in the interrupt handler.

What were you measuring? Rotation?

3

@ Mike - Yeah 5 to me sounds way wrong as well…

4

What were you measuring? Rotation?

5

The disc has a thin slot cut in it with a Sharp IR detector.
I am going to make the slot wider and see if that makes a difference…

6

I would check it out by manually rotating the disc and seeing if all the rotations are being recognized.

Could you be saturating the detector and suffering with poor recovery times?

7

Have done my hand and yes they are being recognised.

Data sheet says IO frequency of 0.3 MHz

8

post the code?

9

Nothing exotic…

            _beam = new InterruptPort(GHI.Premium.Hardware.G120.Pin.P2_13, true, Port.ResistorMode.PullUp, Port.InterruptMode.InterruptEdgeBoth);
            _beam.OnInterrupt += new NativeEventHandler(_beam_OnInterrupt);

void _beam_OnInterrupt(uint data1, uint data2, DateTime time)
 {
       index++;
 }

 void timer_Tick(GT.Timer timer)
 {
       sevenSegment.Display(index);
       index = 0;
  }
10

First, I would only do one edge interrupt, which would half the interrupt rate.

I don’t see the initialization of the timer. I assume the interval is one second?

You have a pullup resistor set. Is this necessary?

11

I did have one edge originally…
Yes the timer is 1 sec.
Not necessary, will try without - out of curiosity why would that make a difference?

12

I was thinking that the pullup was too strong for the detector?