LPC3131/41 Developer’s Kit - User’s Guide
Page 25
Copyright 2012 © Embedded Artists AB
1.
Remove the DBUF_EN jumper during the boot process and then insert the jumper again in
order to use the QVGA and Ethernet functionality on the
LPC31xx Base Board
.
Figure 7 – DBUF_EN jumper location on LPC31xx Base Board
2.
Replace U11 (74LVC1G08), the AND gate found on page 6 of the
LPC31xx Base Board
schematic. Replace it with a XNOR-gate. The AND and XNOR gates have the same truth
table except when both input signals are low. For the XNOR gate the output is high when both
inputs are low. This will also solve the problem, since the databus buffer (U16 on
LPC3131/41
OEM Board
) will not be enabled during NAND boot when both N_STCS0 and N_STCS1 are
low.
Embedded Artists has created a small board with a XNOR gate that can be soldered to the
LPC31xx Base Board
. This board can be ordered free of charge from the support page.
The
board is delivered with a detailed instruction how to solder the
board (5 wires needs to be soldered on the back side of the
LPC31xx Base Board
).
The picture to the right shows the small board with the XNOR
gate.
After the small board has been soldered to the back side of the
LPC31xx Base Board
, the DBUF-EN jumper (pin 1-2 on J40)
shall
NOT
be inserted.
DBUF_EN jumper,
pin 1-2 on J40
