InterruptPort -OnInterrupt time parameter

[Gus_Issa]

However, I should be clear that by comparing I’m not criticising the GHI devices. In fact, so far, I’m really pleased and impressed by them. The interrupt handing - and specifically the timestamping - is the best of all the devices I have, by a long way - and by much more margin than simple differences in clocks would suggest. That points to a quality firmware implementation on GHI’s part. GHI also has the best support for chip hardware of any of the MF manufacturers I’ve used.

Criticism and comments are very okay. Most of our features were added because users like you suggested them. GHI has a full team, not one engineer like most others, and we are very much dedicated ti supporting you. It seem that you already tried our devices and support and I do not need to do any sales pitch here We are glad to have you as a customer.

Maybe you can let us quote you on what you just said about GHI? Can you do this please? http://www.tinyclr.com/forum/15/702/

[terrorgen]

I got OutOfMemoryException around 1 sec after this code is executed:

using System;
using System.IO.Ports;
using System.Threading;

using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;

using GHIElectronics.NETMF.FEZ;
using GHIElectronics.NETMF.Hardware;

namespace SCSUQuadcopter
{
    public class Program
    {
        static PWM pPwm = new PWM((PWM.Pin)FEZ_Pin.PWM.Di10);
        static InterruptPort pInt = new InterruptPort((Cpu.Pin)FEZ_Pin.Interrupt.Di1, false, Port.ResistorMode.PullDown, Port.InterruptMode.InterruptEdgeHigh);
        static OutputPort led = new OutputPort((Cpu.Pin)FEZ_Pin.Digital.LED, false);

        public static void Main()
        {
            pPwm.SetPulse(2000000, 1000000);
            pInt.OnInterrupt += new NativeEventHandler(pInt_OnInterrupt);
            while (true)
            {
            }
        }

        static void pInt_OnInterrupt(uint data1, uint data2, DateTime time)
        {
            Debug.Print(time.Millisecond.ToString() + " ");
            if (led.Read())
                led.Write(false);
            else
                led.Write(true);
            Debug.Print(time.Millisecond.ToString() + "\n");
        }
    }
}

[phil_thedimonds_com]

I got OutOfMemoryException around 1 sec after this code is executed:

What type of signal is driving the interrupt pin (frequency & duration)?

Interrupts queue - if you’re driving the interrupt pin faster than it can be serviced something will break eventually.

[Gus_Issa]

while (true)
            {
            }

This is EXTREMELY bad! You are killing the processor in a dead loop.

Instead use

Thread.Sleep(-1);

[phil_thedimonds_com]

Good catch, Gus. I missed that, but I bet you’ve seen it a hundred times!

For readability’s sake I would recommend that you replace the while(true) with:

            Thread.Sleep(Timeout.Infinite);

TimeOut.Infinite is the same as -1, but it makes it more “portable” and more likely to work if Microsoft make some change to the MF in the future and change the meaning of that -1.

The default program you get when you create a new project has the following code in it. The while(true) is used here because there is a Thread.Sleep inside the loop.

            while (true)
            {
                // Sleep for 500 milliseconds
                Thread.Sleep(500);

                // toggle LED state
                ledState = !ledState;
                led.Write(ledState);
            }
 

[terrorgen]

I m feeding the pwm signal into the interrupt port. It’s 2ms and 50% duty cycle.

I just switched from c embedded programming and this is how it was done in c. I don’t quite get the idea of thread.sleep. Can somebody direct me a tutorial?

[Gus_Issa]

The while loop just makes the execution go crazy on a tight loop. Instead you want to put your thread to sleep to allow the rest of the system to work

In your c code you didn’t have threading

[terrorgen]

Ok got it. I will report my result later.

[terrorgen]

OK, with replacing the infinite loop with Thread.Sleep and removing Debug.Print messages, I get a pulse of 4ms. So the ISR is executed every 2ms. I think it should be alright.

EDIT: argh… I should actually look at the delay time instead… will post results when I get to the lab.