Embedded Artists LPC3250 Developer's Kit V2 EA-OEM-411 EA-OEM-411 Datenbogen

LPC3250 Developer’s Kit v2 - User’s Guide 

Page 64 

 

 

 

Copyright 2013 © Embedded Artists AB 

 

This chapter contains information about how to troubleshoot boards that does not seem to operate 

properly. It is strongly advised to read through the list of tests and actions that can be done before 

contacting Embedded Artists. The different tests can help determine if there is a problem with the 

board, or not. For return policy, please read Embedded Artists’ General Terms and Conditions 
document (can be found at 

http://www.embeddedartists.com/shop/

).

 

The first step is to make sure that powering works properly. The input power interface is described in 

section 4.23 .  

1.  Disconnect the powering and removed the OEM Board, i.e., remove it from the socket (J1). 

All other connections to the OEM Base Board shall also be removed. 

2.  Connect a stable DC supply (+5V, positive center) to J24. Minimum current capability shall be 

1A for this test. The noise level should be minimal, less than 50mV. 

3.  Measure the +5V and +3.3V voltages with the help of the voltage measuring pads on the 

OEM Base Board. 

Acceptable range for the +5V voltage is 4.5V to 5.5V. 

Acceptable range for the +3.3V voltage is +3.2V to +3.4V. 
If the reset-LED is dimming instead of being clearly on or off, it is also a sign that the supply 

voltages are not stable and outside of valid ranges. 

If problem; since the OEM board is disconnected and there is normally no big current 

consumption on passive OEM Base Board, it is likely that some part of the OEM Base Board 

consumes a lot of current. It might be possible to locate the faulty section/component by 
checking component temperatures with the finger tip. Be careful because faulty components 

can get very hot. 

4.  Verify that there are no voltage dips on the supply. A typical indication of this is that the reset-

LED flash from time to time. An oscilloscope can detect voltage dips; measure the supply 

voltage in AC mode. Set horizontal resolution to 50mV per square. Set the trigger to normal 

mode and adjust the trigger to 50mV below the normal level. That way, the oscilloscope will 
trigger every time a voltage dips occurs. By watching the dips it is possible to judge if there is 

a problem, or not. 

5.  Verify that the reset-LED flash when pressing the reset push-button. The LED should also 

light shortly after releasing the push button. The extra “LED on time” is very short but still 

noticeable (typically a 1/5 of a second, i.e., 200mS). 

6.  Disconnect the powering and mount the OEM Board again (in J1). 

Now, measure the +5V and +3.3V voltages again (see step 2 above). If the +5V voltage is 

below acceptable range it is a sign of too weak power supply to the board. If the reset-LED 

starts dimming instead of being clearly on or off, it is also a sign of too weak power supply to 

the board. 

If the reset-LED always light now when the OEM Board is mounted it is a sign of too weak 
power supply or a serious error on the OEM Board. When doing this test, be sure to not have 

any SWD/JTAG interface connected or any external source driving the reset signal. 

Verify that the reset-LED flash when pressing the reset push-button. 

7.  In section 4.3 it is described how to measure the current consumption of the OEM Board. 

Measure the voltage over J2 while pressing the reset push-button constantly. This will give 
the passive current consumption of the OEM Board, i.e., when the board is in reset. Valid 

range is 100-350mV (which corresponds to 20-70 mA). If current consumption is outside of 

this range, it is an indication that something can be wrong with the OEM board. Note that the 

valid range is quite wide. Being outside this does not necessarily mean that something is