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PoKeys / PoKeys56U Digital Output->Latency Too High!

« on: March 26, 2013, 03:16:10 AM »

 
I have been using PoKey's Visual C# example to manually control digital outputs.
The problem is that the latency is about 2ms per bit out!
Since I am controlling 2 stepper motors, I am using 8 digital outputs (each are 1 bit).
This means that sending each 8 bit output takes 16ms!
I need to be able to change all 8 bits in under 1ms if possible.
By latency I mean the time it takes to execute a "set output" command and then start the next command.

I am controlling each bit individually with the function PoKeysDevice_DLL.SetOutput(byte pinID, bool outputState);
Is there a faster function? What about a function that can set more than one pin at a time?



My entire C# solution is attached, ready to run in Visual C# if you want to help me out

Here is the example file I based my code on:
http://www.poscope.com/uploads/files/PoKeysExamples.zip<C#/Example2_BasicPinFunctions>

Here is my main function&file used to measure latency: (note that it takes me 9 seconds to run the while loop 500 times)

Code: [Select]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;


namespace Example2_BasicPinFunctions
{
    class Program
    {

        public enum pinFunctionsEnum
        {
            pinFunctionInactive = 0,
            pinFunctionDigitalInput = 2,
            pinFunctionDigitalOutput = 4,
            pinFunctionAnalogInput = 8,
            pinFunctionAnalogOutput = 16,
            pinInvert = 128
        }

        static void Main(string[] args)
        {           
            // Create PoKeys55 device object
            PoKeysDevice_DLL.PoKeysDevice device = new PoKeysDevice_DLL.PoKeysDevice();
            // Enumerate devices (this step must never be ommited!)
            int iNumDevices = device.EnumerateDevices();
            if (iNumDevices == 0)
            {
                Console.WriteLine("No PoKeys55 devices found!");
                Console.WriteLine("\nPress any key to exit");
                Console.ReadKey();
                return;
            }
            // Connect to first PoKeys55 device
            device.ConnectToDevice(0);

            int i;
            // Set pins as digital output
            for (i = 2; i <= 9; i++)
            {
                device.SetPinData((byte)(i - 1), (byte)(pinFunctionsEnum.pinFunctionDigitalOutput));
            }
            Console.WriteLine("Pins 2-9 set as digital output");


            bool flop = false;
            int j = 0;






////////////////////////////////////////////////////////////////IMPORTANT PART OF THE CODE
            while (true)
            {
                for (i = 2; i <= 9; i++)
                {
                    device.SetOutput((byte)(i - 1), flop); //is there a faster function that this one?
                }
                flop = !flop; //flop alternates true, false, true, false,...
                j++;
                if (j%500==0) {
                    Console.WriteLine("500 more done"); //prints every time the output changes 500 times (9 seconds)
                }
            }
////////////////////////////////////////////////////////////////END IMPORTANT PART OF THE CODE





            // Disconnect from device
            device.DisconnectDevice();


            Console.WriteLine("\nEnd.\nPress any key to exit");
            Console.ReadKey();

        }
    }
}