6-10
MPC8240 Integrated Processor User’s Manual
SDRAM Interface Operation
6.2.2 SDRAM Address Multiplexing
This section describes how the MPC8240 translates processor addresses into SDRAM
memory addresses.
The MPC8240 SDRAM memory address signals SDMA[12:0] are labeled with SDMA12
as the most-significant bit (msb) and SDMA0 as the least-significant bit (lsb). Most
SDRAM devices are labeled with A0 as the least significant address input. Therefore, the
MPC8240 SDMA[12:0] signals should be connected to SDRAM devices according to
Table 6-2.
Table 6-6 shows the multiplexing of the internal physical addresses A[0
msb
:31
lsb
] through
SDBA[1:0] and SDMA[12:0] during the row and column phases when operating in 32-bit
mode.
Table 6-5. Supported SDRAM Device Configurations
SDRAM
Device
Density
Device
Organization
Addressing—Row
Bits x Column
Bits x Logical
Banks
1
1
A logical bank is defined for the MPC8240 as a portion of memory addressed through an SDRAM bank select.
MCCR1
[Bank
n
row]
setting
Number of
Devices in a
Physical Bank
2
,
3
2
A physical bank is defined for the MPC8240 as a portion of memory addressed through an SDRAM chip select.
Certain modules of SDRAM may have two physical banks and require two chip selects to be programmed to
support a single module.
3
Number of devices and size for physical banks are based on a 64-bit data bus, for a 32-bit data bus these
values would be halved.
Physical
Bank Size
(Mbytes)
4
The physical bank size is the amount of memory addressed by a single SDRAM chip select.
16 Mbit
(2 banks)
4M x 4 bits
13 x 8 x 2
5
5
Not supported for 32-bit data bus
0b01
16
32
11 x 10 x 2
0b11
2M x 8 (or 9) bits
11 x 9 x 2
0b11
8
16
1M x 16 (or 18) bits
11 x 8 x 2
0b11
4
8
64 Mbit
(2 banks)
16M x 4 bits
13 x 10 x 2
0b01
16
128
8M x 8 (or 9) bits
0b01
8
64
4M x 16 (or 18) bits
13 x 8 x 2
0b01
4
32
64 Mbit
(4 banks)
16M x 4 bits
12 x 10 x 4
0b00
16
128
8M x 8 (or 9) bits
12 x 9 x 4
0b00
8
64
4M x 16 (or 18) bits
12 x 8 x 4
0b00
4
32
2M x 32 (or 36) bits
11 x 8 x 4
0b00
2
16
128 Mbit
(2 Banks)
16M x 8 (or 9) bits
13 x 10 x 2
0b01
8
128
8M x 16 (or 18) bits
13 x 9 x 2
0b01
4
64
4M x 32 (or 36) bits
13 x 8 x 2
0b01
2
32
128 Mbit
(4 Banks)
16M x 8 (or 9) bits
12 x 10 x 4
0b00
8
128
8M x 16 (or 18) bits
0b00
4
64
4M x 32 (or 36) bits
12 x 8 x 4
0b00
2
32
256 Mbit
(4 banks)
16M x 16 (or 18) bits
0b00
4
128
Summary of Contents for MPC8240
Page 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Page 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Page 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Page 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Page 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Page 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Page 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Page 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Page 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Page 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Page 516: ...16 14 Watchpoint Trigger Applications ...
Page 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Page 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Page 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...