Arduino Uno-I think I hurt something... I2C related
I recently picked up an Uno, an I2C 8x8 LED matrix, and the 16x2 LCD shield kit to begin doing things with.
The first time I put the shield on the Uno it worked fine. I was able to upload the "hello world" example and made some little changes to see how similar the program was to my C++ class that I'm taking. No issues.
I then turned my attention to the 8x8 matrix, but was less than successful with it. It would only blink a couple of LEDs regardless of which program I tried to upload to it. I went back to the LCD shield with no issues.
I picked up a power supply that was center pin negative, realized it after I plugged it in, and swapped the polarity on it. I haven't used it since I swapped the leads.
This morning I plugged the Arduino with LCD shield into the computer, and uploaded the hello world program to start playing again. There were no errors in the compiler, nor in the uploading process. The top, left two digits on the LCD were cycling between numbers and question marks. The buttons would change the backlight color, but would not display any words and the reset seemed to do nothing. I realized that when reset was pressed the hello world would flash for just a brief moment, then go back to the numbers and question marks.
Everything seems to be soldered on the shield that should be, and I replaced the standard height headers for extra long ones after initial testing so I could use the other analog or digital pins in the future.
To me it seems as if maybe I got the IC on the shield to hot during the soldering process, and that explains the issue after swapping the headers. It doesn't explain the LED matrix issue though.
Has anyone seen something like this? Any suggested remedies?