text: PROBLEM FREESCALE CUP | NXP Community
  PROBLEM FREESCALE CUP
  Question asked by Edoardo Cavallotto on Dec 22, 2013
  Latest reply on Jan 20, 2014 by Antonio Quevedo
  Hi, i'm new here and my name is Edoardo.
  For the Freescale Cup i'm using a FRDM-KL25Z and a TFC-Motor Shield.
  When i attach the board to the shield and get power on the shield with the battery the Board not turn on.
  Last modified on Dec 22, 2013 7:11 AM
  Hector Sanchez Jan 6, 2014 8:24 AM
  Does your battery provides enough power to move the TFC-Motor?
  Refer to this site and keep me informed if this helped you: The NXP Cup
  Edoardo Cavallotto @ Hector Sanchez on Jan 17, 2014 1:20 AM
  if the shield is powered by the battery, the board doesn't work. It work only by the USB
  Antonio Quevedo Jan 17, 2014 9:58 AM
  I have had some problems with power on the FRDM KL25 boards on revision E, because there are some changes on power circuits between revisions D and E. Looking at the shield schematic, it can be seen that battery voltage is present at the "+V_BATTERY" node, which is connected to pin 16 of J9 of the FRDM board. This pin is the "P5_9V_VIN" access point for the FRDM.
  If you look at the FRDM revD schematic, you will see that this node is connected to the input of a 3.3V regulator. The 5V power from both USB connectors also go to this point through blocking diodes, so an external battery will shut off 5V power from USBs. If your board is revD, the 7.2V from the batteries tould be directly transformed to 3.3V on the board.
  Now, if you check on revE schematic, you will notice that there is a diode between this connection point and the voltage regulator. I suppose that you may have a problem with this diode, which is D10. I suggest powering the shield board alone with the battery and checking if you find 7.2V on the shield pin 16 of J9 (use pin 14 or 12 of the same connector as reference). If you find the full voltage, connect the battery directly between pins 16 ( + ) and 14 or 12 ( - ) of J9 on FRDM board. If the board does not power up, you may have a problem with D10. In that case, you could substitute this diode, although it is a SMD component. You may also short its terminals, and I believe you would not have any problem with that since D11 and D12 still protect your circuit from problems with connecting both battery and USB.
  Edoardo Cavallotto @ Antonio Quevedo on Jan 20, 2014 5:25 AM
  i solve it. Now the car work perfectly
  Antonio Quevedo ha scritto:
  Antonio Quevedo @ Edoardo Cavallotto on Jan 20, 2014 5:36 AM
  That would be interesting if you could give details on how you solved it. What data did you get from the power lines?