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Old 01-28-2013, 12:10 PM
sirch2 sirch2 is offline
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Default Set Arduino pin to High Impedance (floating)

The circuit shown below is for a 40kHz ultrasonic rangefinder. I have put together a variation of the circuit using an Arduino and not including the I2C code/connector (the original code is in Assembly with which I am not too familiar so I am rewriting it).

The reciever section includes 4 Op Amps, the middle two of which are supposed to provide selectable gain. I am assuming that I need to toggle the resistsors from High Impedance to Low (ground) to change the gain and I can set the relevat pins to OUTPUT, LOW to ground them.

My question is how do I set the pins back to floating in on the Arduino? Would it be enough to set it to HIGH?

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Old 01-28-2013, 12:44 PM
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MrChips MrChips is offline
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There is a register called DDRA. Set this to 0 to set all pins of PORTA to high impedance.
Specifically, set the corresponding bit to 1 that you wish to be an output.
Most computer problems can be attributed to a simple problem - a loosewire behind the keyboard.

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