User manual

LPC4357 Developer’s Kit - User’s Guide

Page 16

Figure 5 – 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.

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 Board. For the LPC4357 OEM Board, the signal BCSY is actually

signal BCS0. This means that the NOR flash is accessible in memory region: 0x1C00 0000 - 0x1CFF

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 LPC4357 OEM Board, the signal BCSX is actually

Expansion Connectors

left to right: J4, J3, J5