User manual

LPC4357 Developer’s Kit - User’s Guide

Page 15

4.2 SP2: OEM Board Connector

The LPC4357 OEM board connector is a standard DDR2 SO-DIMM socket with 200 positions and

0.6mm pitch. It has 1.8V keying (which is what DDR2 stands for). The JEDEC standard defining the

DDR2 SODIMM boards is called JEDEC MO-224.

The signal names are general and represent the OEM base board functionality, rather than the

LPC4357 signal names. This is because the OEM base board also supports other OEM boards.

4.3 SP2: Current Measurements

It is possible to accurately measure current consumption of the LPC4357 OEM board. This can be very

valuable when working with applications that make use of the low power modes of the LPC4357

processors. The circuit is based on the chip ZXCT1010 from Diodes/Zetex. This chip generates a

voltage output proportional to the current through R2. This voltage can be measured over J2. 100mA

gives a 500mV output voltage, or expressed differently, 1mV correspond to 0.2mA

It is possible to remove R1, R2 and/or R3 for measuring current with an external multimeter. Note that

VCC_MAIN and VCC_BUFFERS are connected on the LPC4357 OEM board so there is no difference

between these supplies. This division has been done for compatibility with other OEM boards.

Figure 4 – Current Measurement J2

4.4 SP3: Expansion Connectors

All relevant OEM board signals are available for external use via three 64 pos IDC expansion

connectors; J3, J4 and J5. The expansion connectors are close to the SO-DIMM connectors to

minimize signal distortion.

Note that some OEM board circuits may need to be disconnected before externally used. Carefully

investigate the need for this before using a signal for external expansion.

Note that J4 has gathered all needed signals for expanding the memory bus (16-bit bus expansion). J4

is the expansion connector closest to the board edge. For 32-bit memory bus expansion, J3 is also

needed (for the upper 16 bits of the databus).

Current Measurement

J2 (left: signal, right: gnd)