User manual

LPC3250 Developer’s Kit v2 - User’s Guide

Page 17

Figure 3 – Expansion Connectors J3, J4, J5

4.5 SP4: External Memory Bus

This part of the OEM Base Board demonstrates how the external memory bus can be used for

expansion of custom circuits. Two different devices are connected to the memory bus; a 16-bit parallel

NOR flash and a 16-bit register.

In order to be universal between 16- and 32-bit databus width OEM Boards, only the lower 16 bits are

connected. This does not affect the LPC3250 OEM board since it only exists in 16-bit databus width.

The 16-bit parallel NOR flash is enabled when JP1 is inserted, see picture below for guidance where to

find JP1 on the OEM Base Board. Note that the signal name is cryptic since the OEM Base Board is

compatible with many different OEM Boards. For the LPC3250 OEM Board, the signal BCSY is

actually signal BCS2. This means that the NOR flash is accessible in memory region: 0xE200 0000 -

0xE2FF FFFF.

Also, a 16-bit register is connected to the external memory bus. The 16 bits in the register directly

drives 16 LEDs (a high signal light a LED). The signals are also available on an expansion connector

(J6). It can for example connect to a logic analyzer, for high-bandwidth logging. The upper and lower 8

bits are individually writeable. Signals BBLS0/BBLS1 controls the lower and upper 8 bits, respectively.

Since the OEM Base Board is universal and supports many different OEM Boards, the chip select

signal is either signal BCSX or GPIO69. For the LPC3250 OEM Board, the signal BCSX is actually

Expansion Connectors

left to right: J4, J3, J5