I wanted to be able to use the Motor shield and the Robot LCD & Keypad 1.0 shield at the same time. I was trying to get them to play together with the Mega 2560.
One problem I noticed right off is that the Motor shield and the LCD shield both use Digital pin 12. So I figured it would be easy to just look at the schematic and figure out which wire could easily be moved and reprogrammed.
I don't know what the deal is the the Robot shield but I could not figure out what pin went where or what controlled what. Also, my shield was shipped with connectors (female and male) that, as far as I can tell, went no where. I was finally able to trace out the D7 through D4 pins but no luck with the Enable or RS pins. So I decided to just solder wires to what where silk screened Enable (E) and RS and then hooked them up to D11 and D12 on the Mega 2560. I loaded up the hello world example software it it was displayed as expected.
I just writing this up in case someone else tries to do the same thing.
Next task is to modify the LCD code to use another pin other than Digital Pin 12 so I can use the motor shield at the same time.