I am trying to supply my devkit for MPC5744P with external 12V power supply through header J3 pin 1 connected to +12V and ground to pin 13. I have set the jumper J39 and set J13 to external 12V supply. The supply is made through a 12V battery. The problem is that there seems to be a lot of noise in the supply voltage when I supply through the header(high frequency variations of almost +/-4V). Is there any other jumper that I should be setting? I have no issues when supplying with the PWR in connector in the Devkit. The problem is only when I choose to supply using header J3.