Hi,
I am usinag Ardunio Duemilanove board. I am trying to set TX & RX pins as input pins. But, if i measure the voltage at RX & TX pins it shows 4.5V always. And if i measure voltage at other pins which shows me 200mV ( This pins also set to input mode). How can use RX & TX as a general purpose I/O.
Yes you can but it has the output of the serial / USB chip connected to it through a 1K so any input must override that. Plus you have to disconnect it when uploading.
Hi,
Even i have disconnected the usb and i am powering the unit using external power supply. Then also i am getting 4.5v at both TX & RX pins.all other pins gives me 0v or 250mv. Weather i need to do anything on the 1K resistor or any other options.
It's time you posted your code I think.
Then also i am getting 4.5v at both TX & RX pins.all other pins gives me 0v or 250mv.
Yes you will. The USB / Serial chip is still on the board and is still being powered.
Weather i need to do anything on the 1K resistor or any other options.
You need to connect it to an input that will drive a 1K pull up load to low for using it as an input.
dharani:
And if i measure voltage at other pins which shows me 200mV ( This pins also set to input mode). How can use RX & TX as a general purpose I/O.
I/O is Input/Output.
Did you have Input in mind, or Output?
TX & RX as a input pin.
dharani:
TX & RX as a input pin.
In that case Reply #1 gives you your answer.