UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
104 of 362
NXP Semiconductors
UM10208
Chapter 8: LPC2800 EMC
10.20 Static Memory Configuration Registers (EMCStaticConfig0-2 -
0x8000 8200,20,40)
The EMCStaticConfig0-2 Registers indicate the static memory configuration. These
registers should only be modified during system initialization, or when there are no current
or outstanding transactions. This can be ensured by waiting until the EMC is idle, and then
entering low-power or disabled mode. These registers are accessed with one wait state.
shows the EMCStaticConfig0-2 Registers. Note that synchronous burst mode
memory devices are not supported.
7:2
-
Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
-
9:8
CAS
CAS latency
01: One AHB HCLK cycle
10: Two AHB HCLK cycles
11: Three AHB HCLK cycles
00: Reserved
11
31:10
-
Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
-
Table 97.
Dynamic Memory RAS/CAS Delay Register (EMCDynamicRasCas - 0x8000 8104)
Bit
Symbol
Description
POR Reset
Value
Table 98.
Static Memory Configuration Registers (EMCStaticConfig0-2 - addresses
0x8000 8200, 0x8000 8220, 0x8000 8240)
Bit
Symbol
Description
POR
Reset
Value
1:0
Memory Width This field selects the width of the associated memory. Do not write
the values 10 or 11.
00 8 bits
01 16 bits
00
2
-
Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
-
3
Page Mode
This bit resets to 0. Write a 1 to indicate a page mode device. The
EMC can burst up to four external accesses. Therefore devices
with asynchronous page mode burst four or higher devices are
supported. Asynchronous page mode burst two devices are not
supported and must be accessed using single cycles.
0
5:4
-
Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
-
6
Chip select
polarity
If this bit is zero, as it is after a power-on reset, the associated
chip select line is driven in an active-low fashion. Write a 1 to this
bit to select active-high signalling on the associated chip select
line.
0