Can I use D1 as digital input?

Development Tools IDE 1.x
1

Hi. This is kind as stupid question but, Im having troubles reading on D1 - digital signal from other arduino. I'm not using USB so no interference with serial is expected

I've been looking other posts and documentation and it seems it is possible but it is not clear to me if I have to use an extra resistor connected to gound or what demonds i'm missing....

Thanks in advance

2

What trouble are you having? Have you been able to successfully use other pins for this purpose?

3

Yes, you can. You do not need a resistor. Assuming this is a bord with the 'USB' chip (e.g. an Uno), the TX and RX lines between the 'USB' chip and the micro are protected by a resistor so you don't blow up the 'USB' chip if you do something wrong :wink:

Note that in my opinion using RX/TX for other purposes is a last resort if you run out of pins as the serial port is usefull for debugging purposes. I'd rather use the analog pins first (if possible).