User manual

LPC4357 Developer’s Kit - User’s Guide

Page 62

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

wrong. More symptoms than this is needed to judge if a board is wrong, or not. Do not forget

to press the reset push-button all the time during this measurement. Redo the test in case of

uncertainty.

8. Now, measure the current consumption of the OEM Board when it is running an application. It

is a problem to not have a specified application running because the current consumption can

vary widely between different applications. The current consumption shall increase compared

to the previous test (in case an application is running). It is recommended to download one of

the precompiled sample applications from the LPC4357 Developer’s Kit support page on the

Embedded Artists web site. How to download is explained in next section. The sample

application s_sdram.hex has for example a known current consumption range. The valid

range is 650-900m V (which corresponds to 130-180mA). The current consumption varies

between different sample applications depending on which peripherals that are active. A

running application will in general give a range of 400-700mV (which corresponds to 80-

140mA)

9. In most cases it is possible to power the board via the USB interface, J25 (the UART-to-USB

bridge mini-B USB connector). Redo tests 3) to 8) above again with USB powering. Connect

J25 directly to a PC with the USB cable included in the Developer’s Kit.

Note that not all PC:s and/or laptops can power the board. In such cases, a USB hub with

independent powering can work. In this case, connect J25 to a USB Hub, which in turn is

connected to a PC.

7.3 Contact with OEM Board MCU

The second step is to make sure that the LPC4357 MCU on the OEM Board is working.

Test that it is possible to download one of the precompiled test programs that exist on Embedded

Artists support site. Use the DFUSec application to download code over USB. See section 5.4.1 for

details how to download.

Optionally test that it is possible to download via the JTAG/SWD interface. A JTAG/SWD debug

interface us then needed. The low-cost LPCXpresso target board series from NXP contains a

JTAG/SWD debug interface called LPC-Link™ that can be used for this. Other brands will also work.

7.4 Using Test Program to Verify Correct Operation

The third step is to utilize the just downloaded precompiled sample applications, one after one, to verify

correct operation of individual parts of the OEM Board as well as the OEM Base Board. While doing

these tests, be sure to not have anything connected to the system.