i am new to c# i have been working on controlling a io card
i have no issue writing to turn on / toggle / or get status

turn on bits |= 1 << bit;
toggle bits ^= 1 << bit;

but i cannot get the item pin to turn off i do not want to use toggle because i want it
to either be on or off

now when i turn off the pin basicly unset the pins i always get a error about it setting a negative number to a ushort
any help would be greatly appreciated

bits &= ~(1 << bit);

`
//=============================================================
//program.cs these are my calls from the main program
//============================================================

                if (whatTheUserTyped == "on")
                {

                    Console.WriteLine(Control.PinOn(2,3,4,5,6));

                }



                if (whatTheUserTyped == "off")
                {


                    Console.WriteLine(Control.PinOff(4));
                }
//==========================================================                
// control.cs 
//==========================================================    

public string PinOn(int pin1)
        {
bits |= Convert.ToUInt16(1 << pin1);


return "pin on";

        }


public string PinOff(int pin1)
        {

bits &= ~(1 << 3);
WriteToCard();

return "pin off";
       }        
`

There's usually more than that. That is, not only do you set the port value as you noted but if the pin is input, output, etc. Code alone isn't enough here.

a bits is a numerics single value, either 1 or 0 that encodes a single unit of digital information. A byte is a sequence of bits; usually eight bits equal one byte.

Few things here i cant seem to understand in ur code:
-your pinon method takes only 1 argument of type int, but u seem to be passing 5 integer values.
- pinoff method takes a argument and being used at all.

It will be helpful if you could give a intro on ur io card and what exactly u are trying to achieve when u set and unset each bit.

its not the full code since it it long i have overflow meadthods that take more and more but i striped the program to barebones
to not make it a long read i included what i am doing to turn the card pins on and add off i have no issue posting
more of the code also i am working with turning the relays on and off and on the card itself you write to either offset 0 controls 0-7 and offset 4 controls 7-8, the byte itself uint16 or ushort also the code is enough only thing missing
is the WriteToCard(); function and the declared variables of bits to make this work, my main issue that i am having is using the
bitwise to unset the pin

i figured it out

bits & ~(1 << pin)

will actully work when you put it into a static int and return bits & ~(1 << pin)

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