3.6" TFT LCD Shield for Arduino Mega not working on a custom board using 2560

Hello,

I recently purchased a 3.6" TFT LCD Shield for arduino mega 2560, that works perfectly with the mega. However, I made a custom board with an atmega2560 chip, and when I tried to connect the shield to it using connectors, I end up getting a white screen. I don't have a pinout of the shield as such, but I have connected the 16 data pins, 4 control pins and power supply to the same corresponding pins on the custom board. Please help me in debugging this issue!

Thanks