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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Expansion Bus
Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
656
Order Number: 306262-004US
Table 220.
Expansion Bus Address and Data Byte Steering (Sheet 1 of 3)
AHB Bus
Cycle
Device Width
Connected to
Expansion Bus
(8-bit or 16-bit
or 32-bit)
AHB Address
Value
(AHB_ADDR[1:0]
)
Expansion Bus
Address Value
(EX_ADDR[1:0]
)
Data Location Translation Between Expansion
Data Bus and AHB Data Bus
Word write
8-bit
00
00
AHB data bus [31:24] = Expansion data bus [7:0],
EX_BE_N = 0xE
01
AHB data bus [23:16] = Expansion data bus [7:0],
EX_BE_N = 0xE
10
AHB data bus [15:8] = Expansion data bus [7:0],
EX_BE_N = 0xE
11
AHB data bus [7:0] = Expansion data bus [7:0],
EX_BE_N = 0xE]
Word write
16-bit
00
00
AHB data bus [31:16] = Expansion data bus
[15:0], EX_BE_N = 0xC
10
AHB data bus [15:0] = Expansion data bus [15:0],
EX_BE_N = 0xC
Word write
32-bit
00
00
AHB data bus [31:0] = Expansion data bus [31:0],
EX_BE_N = 0x0
Word read
8-bit
00
00
AHB data bus [31:24] = Expansion data bus [7:0],
EX_BE_N = 0xE
01
AHB data bus [23:16] = Expansion data bus [7:0],
EX_BE_N = 0xE
10
AHB data bus [15:8] = Expansion data bus [7:0],
EX_BE_N = 0xE
11
AHB data bus [7:0] = Expansion data bus [7:0],
EX_BE_N = 0xE]
Word read
16-bit
00
00
AHB data bus [31:16] = Expansion data bus
[15:0], EX_BE_N = 0xC
10
AHB data bus [15:0] = Expansion data bus [15:0],
EX_BE_N = 0xC
Word read
32-bit
00
00
AHB data bus [31:0] = Expansion data bus [31:0],
EX_BE_N = 0x0
Halfword
read
8-bit
0x
00
AHB data bus [31:24] = Expansion data bus [7:0],
EX_BE_N = 0xE
01
AHB data bus [23:16] = Expansion data bus [7:0],
EX_BE_N = 0xE
Halfword
read
8-bit
1x
10
AHB data bus [15:8] = Expansion data bus [7:0],
EX_BE_N = 0xE
11
AHB data bus [7:0] = Expansion data bus [7:0],
EX_BE_N = 0xE]
Halfword
read
16-bit
0x
00
AHB data bus [31:16] = Expansion data bus
[15:0], EX_BE_N = 0xC
Halfword
read
16-bit
1x
10
AHB data bus [15:0] = Expansion data bus [15:0],
EX_BE_N = 0xC
Halfword
read
32-bit
0x
00
AHB data bus [31:16] = Expansion data bus
[31:16], EX_BE_N = 0x3
Halfword
read
32-bit
1x
00
AHB data bus [15:0] = Expansion data bus [15:0],
EX_BE_N = 0xC
Halfword
write
8-bit
0x
00
AHB data bus [31:24] = Expansion data bus [7:0],
EX_BE_N = 0xE
01
AHB data bus [23:16] = Expansion data bus [7:0],
EX_BE_N = 0xE