6-14
MPC8240 Integrated Processor User’s Manual
SDRAM Interface Operation
The data path between the internal processor core bus and the external memory bus for
flow-through buffer mode is shown in Figure 6-4.
Figure 6-4. SDRAM Flow-Through Memory Interface
The registered buffer mode interface is shown in Figure 6-5. The registered buffer mode
allows a higher memory interface frequency at the expense of a clock cycle of latency on
SDRAM reads.
Table 6-9. SDRAM System Configurations
RAM_TYPE
EDO
PCKEN
WRITE _P
ARITY_CHK
INLRD_P
ARECC _CHK_EN
INLINE_P
AR_NO
T_ECC
B
UF_TYPE[0]
B
UF_TYPE[1]
RMW_P
AR
ECC_EN
MEM_P
ARITY_ECC_EN
MB_ECC_ERR_EN
Description
0
0
0
0
0
0
0
0
0
0
0
0
Ffow-through, no ECC or parity
0
0
0
0
0
0
0
1
0
0
0
0
Registered, no ECC or parity
0
0
1
0
0
0
0
0
0
0
1
0
Flow- through parity
0
0
1
0
0
0
0
1
0
0
1
0
Registered buffer parity
0
0
1
0
0
0
0
0
1
0
1
0
Flow- through RMW parity
0
0
1
0
0
0
0
1
1
0
1
0
Registered buffer RMW parity
0
0
0
0
0
0
1
0
0
0
0
0
In-line, no parity
0
0
0
1
1
1
1
0
0
0
1
0
In-line, parity enabled
0
0
0
1
1
1
1
0
1
0
1
0
In-line, RMW parity enabled
0
0
0
1
1
0
1
0
1
0
1
1
In-line, ECC enabled
SDRAM data path
External Data from SDRAM
Data Signals
Internal Data to SDRAM
Output Enable
Содержание MPC8240
Страница 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Страница 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Страница 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Страница 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Страница 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Страница 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Страница 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Страница 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Страница 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Страница 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Страница 516: ...16 14 Watchpoint Trigger Applications ...
Страница 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Страница 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Страница 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...