UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
109 of 362
NXP Semiconductors
UM10208
Chapter 8: LPC2800 EMC
For example, for a static memory read/write transfer time of 16 µs, and a HCLK frequency
of 50 MHz, the following value must be programmed into this register:
10.28 EMC Miscellaneous Control Register (EMCMisc - 0x8000 5064)
This register is in the System Control address range, and affects both static and dynamic
memory.
Table 105. Static Memory Extended Wait Register (EMCStaticExtendedWait - address
0x8000 8080)
Bit
Symbol
Value Description
Reset
Value
9:0
EXTENDEDWAIT
If the ExtendedWait bit in the EMCStaticConfig
Register is 1, this fields controls the length of the
assertion of OE, WE, and BLS in read and write
cycles. These control signals are asserted for
(EXTEND 1)
×
16
×
t
HCLK
. If the minimum
read and write cycles for the device have different
value, use longer of the two to determine the value of
this field.
0
31:10 -
-
Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is
not defined.
-
16
10
6
–
×
50
×
10
6
×
16
--------------------------------------------------
1
–
49
=
Table 106. EMC Miscellaneous Control Register (EMCMisc - address 0x8000 5064)
Bit
Symbol
Description
Reset
Value
0
SRefReq
This bit is an alternative method of placing external SDRAM in
self-refresh mode (the other being bit 2 in the
EMCDynamicControl register). A 1 in this bit places the SDRAM
in self-refresh mode.
0
7:1
-
Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
-
8
Rel1Config
This bit controls how the EMC places static memory addresses
on the A20:0 pins. When this bit is 0, as it is after a Reset, the
EMC shifts the address down by 1 bit for accesses to 16-bit
memories, so that A0 should be connected to the lowest-order
address line of both 8- and 16-bit memories. When this bit is 1,
the EMC does not shift address bits for accesses to 16-bit
memories, so that A1 should be connected to the lowest-order
address line of 16-bit memories, while A0 should be connected to
the lowest-order address line of 8-bit memories.
0
31:9
-
Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
-