UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
111 of 362
NXP Semiconductors
UM10208
Chapter 8: LPC2800 EMC
12. Some SDRAMs also have an Extended Mode Register. To set this register, again read
an address containing the value for the Extended Mode Register in the row address
bits, but set address bit BA1 to 1 to load the Extended Mode Register. The location of
BA1 in the memory address is shown in the rightmost 2 columns of Table 96 on
page 102. Again, add 0x3000 0000 or 0x5000 0000 to that value, and read the
resulting address.
13. Write all zeroes to the EMCDynamicControl Register. This changes the command to
the SDRAM(s) to NORMAL which protects the Mode register, and also saves power
by only driving clocks and setting Clock enable during SDRAM operations.
14. Set bit 19 (0x0080 0000) in the EMCDynamicControl Register to enable the buffers.
This improves operational efficiency. The SDRAM is now ready for normal operation.
12. SDRAM usage notes
This section uses the Micron MT48LC8M16A2 module (8 M
×
16 bit) as an example of
how to program the MODE register in this SDRAM module:
The Micron MT48LC8M16A2 module has 4 K rows and 512 columns. The address
mapping is shown in
. For other address mapping configurations, see also
and
.
, Bn is the byte address in a 32-bit word, Cn is he column address, Rn is
the row address, and BAn is the bank address.
Programming the Micron MT48LC8M16A2 mode register
The MODE register in the Micron MT48LC8M16A2 module has the following format:
Table 107. MT48LC8M16A2 address table
8 M
×
16 bit
Configuration
2 M x 16 x 4 banks
Refresh count
4 K
Row addressing
4 K (A0 - A11)
Bank addressing
4 (BA0, BA1)
Column addressing
512 (A0 - A8)
Table 108. 16-bit memory bus width
SDRAM address mapping: 4 K rows, 512 columns
A27
A26
A25
A24
A23
A22
A21
A20
A19
A18
-
-
-
-
BA1
BA0
R11
R10
R9
R8
A17
A16
A15
A14
A13
A12
A11
A10
A9
A8
R7
R6
R5
R4
R3
R2
R1
R0
C8
C7
A7
A6
A5
A4
A3
A2
A1
A0
C6
C5
C4
C3
C2
C1
C0
B0