Chapter 6. MPC8240 Memory Interface
6-13
SDRAM Interface Operation
6.2.3 SDRAM Memory Data Interface
To reduce loading on the data bus, the MPC8240 features on-chip buffers between the
internal processor core data bus and the memory data bus. The MPC8240 supports three
types of internal data path buffering for the SDRAM data interface—flow-through,
registered, and in-line buffer mode. Flow-through buffer mode is the default mode for the
MPC8240.
Table 6-8 lists the parameters that determine the data path buffer mode and also control the
parity or ECC operation of the MPC8240.
Table 6-9 describes the parameter settings for the available SDRAM data path buffer
options. Note that configuration register bit settings that are not specified in Table 6-9 have
undefined behavior.
11x8x4
or
12x8x4
SDRAS
1
1
B
A
1
B
A
0
1
0
9 8 7 6 5 4 3 2 1 0
SDCAS
B
A
1
B
A
0
7 6 5 4 3 2 1 0
Table 6-8. Memory Data Path Parameters
Bit Name
Register and
Offset
Bit Number
in Register
RAM_TYPE
MCCR1 @F0
17
EDO
MCCR2 @F4
16
PCKEN
MCCR1 @F0
16
WRITE _PARITY_CHK
MCCR2 @F4
19
INLINE_RD_EN
MCCR2 @F4
18
INLINE_PAR_NOT_ECC
MCCR2 @F4
20
BUF_TYPE[0]
MCCR4 @FC
22
BUF_TYPE[1]
MCCR4 @FC
20
RMW_PAR
MCCR2 @F4
0
ECC_EN
MCCR2 @F4
17
MEM_PARITY_ECC_EN
ErrEnR1 @C0
2
MB_ECC_ERR_EN
ErrEnR2 @C4
3
Table 6-7. SDRAM Address Multiplexing SDBA[1:0]
and SDMA[12:0]—64-Bit Mode (Continued)
Row x Col x Bank
msb
Physical Address
lsb
0-2
3 4 5 6 7
8
9
1
0
1
1
1
2
1
3
1
4
1
5
1
6
1
7
1
8
1
9
2
0
2
1
2
2
2
3
2
4
2
5
2
6
2
7
2
8
2
9
3
0
3
1
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 ...