User manual

LPC4357 Developer’s Kit - User’s Guide
Page 56
Copyright 2012 © Embedded Artists AB
Figure 35 – Identifying R163
Note that R163 has been removed on all boards shipped out from Embedded Artists after May
15, 2012. Since there is a transition period, and stock at distributors, there is no guarantee that the
resistor has been removed on boards delivered after this date. Please always check if the board has
R163 removed. If not, remove R163.
5.6.4 Initialization of External Memory Bus
The databus buffers (U12, U14 on LPC4357 OEM board) to the external memory bus are controlled by
the OE and BLSx signals. Even though the external memory bus is not used, OE and BLSx are
reserved and cannot be used for other purposes. This is also true if only the SDRAM is used but not
the static memory areas. The BLS0, BLS1, BLS2 and BLS3 must be set as outputs and set high in
order not to enable the databus buffers.
It is recommended to initialize the EMC peripheral and associated pins fully (for both SDRAM and
static memory regions).
5.6.5 USB OTG Transceiver
The USB OTG transceiver (U31, MIC2555) exists in two versions, -0YML and -1YML. Either one can
be mounted on the OEM Base Board. The difference is the I2C address that the chip answers to. Any
software using the MIC2555 must check which I2C address the chip responds to.
5.6.6 External SDRAM Clock Frequency and CLK2_OUT
This note applies for LPC4357 OEM board, revision A1. See also separate note on product page for
the board.
Signal CLK2_OUT (pin CLK2 on the LPC4357) is available at SODIMM pad/pin 115 on the LPC4357
OEM board. When the external SDRAM is used, signal CLK2_OUT cannot be used for anything. It is
an SDRAM clock signal and any distortion on the signal will affect SDRAM operation.
Remove R163