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Arduino Input pin Mode

Former Member

I would like to know, if a pin needs to be used as an input, is it necessary to use

 

digitalWrite (pin,HIGH).

 

 

Is it better to define the pin to be used as input as an integer type or using #define ??

 

 

The reason why I'm asking is, I need to send a message whenever, pin 9 become high (or low) , but the problem, I'm facing is that the message is sent as soon as the program is uploaded to the board.

 

Pls help!!!

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  • Bobby

    I presume you've looked at http://arduino.cc/en/Reference/DigitalRead

    The digitalWrite (pin,HIGH) sets the pullup-resistor and makes it always appear HIGH until pulled down, by an external contact, pushbutton, etc.

     

    You haven't included the code, but one can presume you have a switch that puts 5v onto Pin9 to send the message.

    In that case have you included a resistor betwen the pin and ground to 'hold' the pin LOW until the +5v arrives via the switch to pull it HIGH.??

     

     

    Its rather hard to decpiher what is happening without including the code, and a circuit drawing or explanation of how its been wired.

     

    You can use some debugging at various points to send a message to the terminal, to see whats going on.

    A few delays added along with the debug message help to slow things down to human speed.

     

     

    Mark

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  • Bobby

    I presume you've looked at http://arduino.cc/en/Reference/DigitalRead

    The digitalWrite (pin,HIGH) sets the pullup-resistor and makes it always appear HIGH until pulled down, by an external contact, pushbutton, etc.

     

    You haven't included the code, but one can presume you have a switch that puts 5v onto Pin9 to send the message.

    In that case have you included a resistor betwen the pin and ground to 'hold' the pin LOW until the +5v arrives via the switch to pull it HIGH.??

     

     

    Its rather hard to decpiher what is happening without including the code, and a circuit drawing or explanation of how its been wired.

     

    You can use some debugging at various points to send a message to the terminal, to see whats going on.

    A few delays added along with the debug message help to slow things down to human speed.

     

     

    Mark

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