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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Memory Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
592
Order Number: 306262-004US
shows the correct programming values for the 32-bit DDRI SDRAM Size
Register.
Example 21. Address Register Programming Example (Default Mode for IXP45X/IXP46X
network processors)
The user wants to program the DDRI SDRAM memory space to begin at 0000 0000H.
Bank 0 is 128 Mbyte and Bank 1 is 128 Mbyte yielding a total memory of 256 Mbytes.
All the memory is programmed for 32-bit mode, so there is no special 32-bit region
using S32SR register. The memory space summary is:
The registers would be programmed as follows:
• Bank 0 Size = 128MB, code = 000100
2
• Bank 1 Size = 128MB, code = 000100
2
• SDBR =0000 0000H, SDBR[30:25] = 000000
2
• SBR0[6:0] = 0000100
2
= 08H (size of Bank 0)
• SBR1[6:0] = 0001000
2
= 10H (size of Bank 0 + size of Bank 1)
• S32SR[29:20] = 000H, S32SR = 0000 0000H (same as default value)
Additionally, the following registers also need to be programmed before using the DDRI
•
DDRI SDRAM Control Register 0 SDCR0
- Program according JEDEC specs.
•
DDRI SDRAM Control Register 1 SDCR1
- Program according JEDEC specs.
•
- Program only if ECC is enabled
Equation 1. Programming Value for DDRI SDRAM Boundary Register 0 (SBR0[6:0])
SBR0[6:0] = Bank 0 Size Code+ SDBR[30:25]
Equation 2. Programming Value for DDRI SDRAM Boundary Register1 (SBR1[6:0])
SBR1[6:0] = Bank 1 Size Code + SBR0[6:0]
Table 207.
Programming Values for the DDRI SDRAM 32-bit Size Register
(S32SR[29:20])*
32-bit Region Size
S32SR[29:20]
32-bit Region Size
S32SR[29:20]
Empty
000H
32 M
020H
1 M
001H
6 4M
040H
2 M
002H
128 M
080H
4 M
004H
256 M
100H
8 M
008H
512 M
200H
16 M
010H
(reserved)
all other values
Note:
For the IXP45X/IXP46X network processors, this is always programmed to 0.
Memory Space Limit
Address
DDRI SDRAM Base
0000 0000H
32-Bit Region Top (end 32-bit region)
N/A
Invalid Region Top (start 64-bit region)
N/A
Bank 0 Top
07FF FFFFH
Bank 1 Top
0FFF FFFFH