Pin States

Hi all,

I have an atmega328 TQFP in a custom board. I have loaded the arduino bootloader successfully. I also have a dual coil latching relay connected to 2 transistors and 2 resistors on digital pins 4 & 5. However, I destroyed my last atmega chip somehow, I thought I had bought the wrong relay type, but I have a new chip and a new relay and have disconnected the relay so I can watch the pulse on my digital pins. Pin 5 seems to be functioning properly, with the pin held low and pulses high. However, pin 4 seems to be held high all the time, even when I have set the state to low. I am trying to figure this out before I connect the relay so I don't have constant current going into the relay and destroying it. So basically, there is nothing connected to those digital pins right now and Im just trying to watch the low/high/low switch. Any reason that pin could be held high?

As a side question, does anyone know what states those pins are in when the arduino boots up? I dont want to activate my relay prematurely.

Thanks in advance.

So basically, there is nothing connected to those digital pins right now and Im just trying to watch the low/high/low switch. Any reason that pin could be held high?

It's possible you got the pin mode statement wrong on the second pin and have the internal pull-up resistor enabled? Post your code you are using.

All pins default to input mode on a reset or power up cycle. Not sure what pins the bootloader may change from that condition.

Lefty