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SDRAM Controller (SDRAMC)
Freescale Semiconductor
21-17
Any chip-select can be enabled or disabled, independent of others. Any chip-select can be allocated any
size of address space from 1M to 4G, independent of others. Any chip-select address space can begin at
any size-aligned base address, independent of others.
For contiguous memory with different sizes of memory blocks, place largest block at the lowest address
and place smaller blocks in descending size order at ascending base addresses.
For example, assume a system with 2 chip selects: CS0=16M, CS1=256M:
CS0CFG = 0x4F000017 = enable 16M @ 0x4F000000-0x4FFFFFFF
CS1CFG = 0x5000001B = enable 256M @ 0x50000000-0x5FFFFFFF
This gives 272 MB total memory, at 0x4F000000-0x5FFFFFFF.
21.5
Functional Description
21.5.1
SDRAM Commands
When an internal bus master accesses SDRAM address space, the memory controller generates the
corresponding SDRAM command.
lists SDRAM commands supported by the memory
controller.
19–5
Reserved, must be cleared.
4–0
CSSZ
Chip select size.
Table 21-10. SDRAM Commands
Function
Symbol
CKE
CS
RAS
CAS
WE
BA[1:0]
A[10]
Other A
Command Inhibit
INH
H
H
X
X
X
X
X
X
No Operation
NOP
H
L
H
H
H
X
X
X
Table 21-9. SDCS
n
Field Descriptions (continued)
Field
Description
CSSZ
Size
Address Lines
to Compare
CSSZ
Size
Address Lines
to Compare
00000
Disabled
—
11000
32 MByte
A[31:25]
00001–10001
Reserved
Reserved
11001
64 MByte
A[31:26]
10010
Reserved
Reserved
11010
128 MByte
A[31:27]
10011
1 MByte
A[31:20]
11011
256 MByte
A[31:28]
10100
2 MByte
A[31:21]
11100
512 MByte
A[31:29]
10101
4 MByte
A[31:22]
11101
1 GByte
A[31:30]
10110
8 MByte
A[31:23]
11110
2 GByte
A31
10111
16 MByte
A[31:24]
11111
4 GByte
Ignore A[31:20]
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...