Currently I am using Arduino UNO which is using ATMega328. My design require plenty of IOs which forced me to use D0 and D1 and trigger input.
On the UNO Rev 3 board. The D0 and D1 are also connected to RxD and TxD on hardware. Configured both as input pins. I tried to place and external 10k pull up to both, used a tact switch to turn it low when pressed. This works find, however, it affected the programming. I need to disconnect the D0(RxD) whenever I need to program the UNO board. Else, there will be a always High on RxD which affect this.
My basic purpose is to get this port works as a switch input, whether active high or low. I remember previous I turned on the internal pull up but doesn't work as well.
Does anyway one has experience using D0 or D1 as input?