UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
92 of 362
NXP Semiconductors
UM10208
Chapter 8: LPC2800 EMC
10.1 EMC Control Register (EMCControl - 0x8000 8000)
The EMCControl Register is a read/write register that controls operation of the memory
controller. The control bits can be altered during normal operation.
shows the
EMCControl Register.
[1]
The external memory cannot be accessed in low-power or disabled state. If a memory access is performed
an AHB error response is generated. The EMC registers can be programmed in low-power and/or disabled
state.
Table 78.
EMC Control Register (EMCControl - address 0x8000 8000)
Bit
Name
Description
POR
Reset
Value
0
MPMC
Enable
This bit is set, so that the EMC is enabled, by both power-on and warm
reset. Write a 0 to this bit to disable the EMC, when the EMC is in idle
state.
Disabling the EMC reduces power consumption. When the
EMC is disabled, the memory is not refreshed. Write a 1 to this bit to
re-enable the EMC.
1
1
Address
Mirror
This bit is set by power-on reset. When this bit is 1, accesses to the
address ranges that would otherwise activate chip select 0, activate
chip select 1 instead. In applications that allow booting from external
memory, connect chip select 1 to the external device from which the
system should boot. Write a 0 to this bit to make chip selects 0 and 1
independent.
1
2
Low
Power
Mode
This bit is cleared by both power-on and warm reset. Write a 1 to this
bit to put the EMC into low-power mode, when the EMC is in idle
state.
. Low-power mode reduces memory controller power
consumption. Dynamic memory is refreshed as necessary. Write a 0 to
this bit to restore normal mode.
0
31:3
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
-