glcd with arduino mega, some an-inputs unavailable


I'm using a KS0108 128x64 glcd from adafruit with my arduino mega. I wired everything up according to "pinout B" on the wiki. The glcd works wonderfully. So do sensors placed on analog inputs 0-7.

However, analog inputs 8-15 don't seem to work. I get crazy values (like when the ADC is connected to a floating pin). Is this normal? Does the glcd library render some (unconnected) pins on the arduino mega unusable?

Thanks in advance! -JFM

However, analog inputs 8-15 don't seem to work

There is a bug in the Arduino IDE version 17 that causes analog inputs 8-15 on mega boards not to work. The bug in not in version 16 and the bug will be corrected in version 18 due out soon. There is a fix posted here somewhere in the forum for correcting version 17 if you wish to look for it and install it. You just have to edit one line in one of the core libraries.

Edit: Here it is: