External Memory Controller (EMC)
41
Philips Semiconductors
Preliminary User Manual
LPC2119/2129/2292/2294
ARM-based Microcontroller
PIN DESCRIPTION
REGISTER DESCRIPTION
The external memory controller contains 4 registers as shown in Table 7.
Each register selects the following options for its memory bank:
• The number of idle clock cycles inserted between between read and write accesses in this bank, and between an access in
another bank and an access in this bank, to avoid bus contention between devices (1 to 17 clocks)
• the length of read accesses, except for subsequent reads from a burst ROM (3 to 35 clocks)
• the length of write accesses (3 to 19 clocks)
• whether the bank is write-protected
• whether the bank is 8, 16, or 32 bits wide
Pin Name
Type
Pin Description
D[31:0]
Input/
Output
External memory data lines.
A[23:0]
Output
External memory address lines.
OE
Output
Low-active Output Enable signal.
BLS[3:0]
Output
Low-active Byte Lane Select signals.
WE
Output
Low-active Write Enable signal.
CS[3:0]
Output
Low-active Chip Select signals.
Table 6: External Memory Controller Pin Description
Address
Name
Description
Access
0xFFE00000
BCFG0
Configuration register for memory bank 0
Read/Write
0xFFE00004
BCFG1
Configuration register for memory bank 1
Read/Write
0xFFE00008
BCFG2
Configuration register for memory bank 2
Read/Write
0xFFE0000C
BCFG3
Configuration register for memory bank 3
Read/Write
Table 7: External Memory Controller Register Map