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Wrong trackbar value when using it to control leds brightness

Discussion in 'C#' started by firstoption, Apr 19, 2014.

  1. firstoption

    firstoption New Member

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    Good day to all,
    Please i need your support on how to solve this problem.I am using the Trackbar to control the brightness of Leds but the value of the Trackbar I am getting in(%) does not corespond to the led's brightness.For example if i move the Trackbar slider to say 50%,the Oscilloscope will show something like 30%,if i move the slider further say to 80%,the Oscilloscope may show something like 50% or 60% or at times the PWM Signal will disappear.I have gone through my codes but i was unable to locate the error.My assumption is that the calculation and conversion i made contain
    error but i do not know how to figure it out.i will highly appreciate it if somebody could put me through on how to sort the problem .Below are my codes:
    C# CODE://this is code the Graphic User Interface uses in order to send data to the microcontroller
    Code:
            private void button3_Click(object sender, EventArgs e)
            {
                
                string  dataToWrite = "a" ;
                UInt32 numBytesWritten = 1;
                myFtdiDevice.Write(dataToWrite, dataToWrite.Length, ref numBytesWritten);
    
            }
    
            private void button4_Click(object sender, EventArgs e)
            {
                string dataToWrite = "b";
                UInt32 numBytesWritten = 1;
                myFtdiDevice.Write(dataToWrite, dataToWrite.Length, ref numBytesWritten);
    
            }
    
    
            private void trackBar1_Scroll(object sender, EventArgs e)
            {  
                UInt32 numBytesWritten = 1;
    
                int percent = (int)(((double)trackBar1.Value / (double)trackBar1.Maximum) * 100);
                label2.Text = (percent.ToString()) + "%";
     
                 if(percent <= 9)//this IF condition send string from "0" to "9"
                   {
                       chdata[0] = "1";
                       myFtdiDevice.Write(chdata[0], chdata[0].Length, ref numBytesWritten);
                       chdata[0] = Convert.ToString(percent);
                       myFtdiDevice.Write(chdata[0], chdata[0].Length, ref numBytesWritten);
                   }
                   else //this ELSE  condition sends string from "10" to "99"
                   {
                       chdata[0] = "2"; // The  "2" here  represents the length of the string being sent
                       myFtdiDevice.Write(chdata[0], chdata[0].Length, ref numBytesWritten);
                       dgdata[0] = percent/ 10;
                       chdata[0] = Convert.ToString(dgdata[0]);
                       myFtdiDevice.Write(chdata[0], chdata[0].Length, ref numBytesWritten);
                       dgdata[1] = percent % 10;
                       chdata[0] = Convert.ToString(dgdata[1]);
                       myFtdiDevice.Write(chdata[0], chdata[0].Length, ref numBytesWritten);
                  
                   }
             
                
              }
    
    
    
    C-CODE SECTION://This code is used by the microcontroller to process the data it receives from the Graphic User Interface.
    Code:
    int wait_command(void)
    
    {
            unsigned char  InData;
    	unsigned char  InBuffer[50];
    	unsigned int   length;
            unsigned int   trackvalue=0;
    	unsigned short pwr_led1=655;
            int   i;
            int   length;
    	
    	InData = USART_Receive();
    	
    	if(InData =='a' || InData =='b' )
    	{
    	    InBuffer[0]= InData;
    	}
    	
    	else if(InData >='0' || InData <= '9'  )
    	{
    		length = InData - '0';//lenght variable here is used to get the actual value sent from GUI.Lenght is 1 for string from "9" to "9" while it is 2 for string from "10" t "99"
    		for (i = 0; i<length; i++)
    		{
    			trackvalue *=10;
    			trackvalue += USART_Receive()- '0';
    			pwr_led1= 655 * trackvalue;
    			_delay_ms(200);
    			
    			
    		}	  
    	}
    	
    	else  
    	{
    	   // do nothing	
    	}
    
       switch(InBuffer[0])
    	{
    				
    	 case 'a':
    	 if (led1_on == 1) led1_on=0; else led1_on=1;
    	 break;
    	 case 'b':
    	 if (led2_on == 1) led2_on=0; else led2_on=1;
    	 break;
             default:
    	 break;	
    
    	}  // switch
    	
    	SetRegister(pwr_led1*spur1_on,pwr_led2*spur2_on);
    	GenerateLatch();
     }
    
    
    I would be very glad if somebody could guide me on how to solve this problem.Thank you all for the usual support.
    Best regards.
    Firstoption.
     

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