9.6.2 Memory Controller registers details
9.6.2.1
MEMSCONR - SDRAM configuration register
This register sets the SDRAM data and address bus properties.
Access
This register can be read/written in 32-bit units.
Address
<MemC_Base> + 00
H
Initial Value
0014 2F48
H
. This register is initialized by any reset.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
0
R
R
R
R
R
R
R
R
R
R
R
R/W
R/W
R/W
R/W
R/W
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
DDATAW
[1:0]
a
COLADDRW[3:0]
ROWADDRW[3:0]
BKADDRW
[1:0]
0
0
0
R/W
R/W
R/W
R/W
R/W
R
R
R
a
For Ravin-L the default value "01
B
" of DDATAW[1:0] must be changed to "00
B
".
Writing to the read-only bits is ignored, reading returns undefined values.
Caution
1.
Ravin-L provides only a 16-bit external memory data bus. Thus the
default value "01
B
" of bit 14 to 13 (DDATAW[1:0]) must be changed
to "00
B
" after any reset and must not be altered afterwards.
2.
The default value
-
"1" of bits 20 and 18
-
"0" of bits 19 and 17 to 15
must not be changed.
Bit
Bit name
Function
14 to 13
DDATAW[1:0]
Specifies SDRAM data width
00
B
16 bit
01
B
32 bit for Ravin-M only (default)
all other prohibited
Caution:
For Ravin-L DDATAW[1:0] must be changed to 00
B
after reset.
12 to 9
COLADDRW
[3:0]
Number of address bits for column address
0111
B
8 bit (default)
1000
B
9 bit
1001
B
10 bit
1010
B
11 bit
1011
B
12 bit
1100
B
13 bit
External Memory Interface Controller
Chapter 9
Preliminary User's Manual S19203EE1V3UM00
315
Содержание uPD72257
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