Chapter 6. MPC8240 Memory Interface
6-63
FPM or EDO DRAM Interface Operation
the memory data path but also to correct single-bit errors in the 64-bit data path. The ECC
logic in the MPC8240 detects and corrects all single-bit errors and detects all double-bit
errors and all errors within a nibble. Other errors may be detected but are not guaranteed to
be either detected or corrected. Multiple-bit errors are always reported when detected.
However, when a single-bit error occurs, the single-bit error counter register is
incremented, and its value is compared to the single-bit error trigger register. If the values
are not equal, no error is reported; if the values are equal, then an error is reported. Thus,
the single-bit error registers may be programmed so that minor faults with memory are
corrected and ignored, but a catastrophic memory failure generates an interrupt. The
syndrome equations for the ECC code are shown in Table 6-23 and Table 6-24. For
supported configurations, see Table 6-17.
.
Table 6-23. The MPC8240 FPM or EDO ECC Syndrome Encoding (Data bits 0:31)
Syndrome
Bit
Data Bit
0 1 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
0
x x x x x x x x x x x x x x x x
x
x
x
x
1
x
x
x
x
x x x x x x x x x x x x x x x x
2
x
x
x
x
x
x
x
x
3
x
x
x
x
x
x
x
x
4
x
x
x
x
x x
x x
x x
x x
5
x x x x
x x x x
x x x x
x x x x
6
x x x x x x x x
x x x x x x x x
7
x x x x
x x x x x x x
x
x x x x
Table 6-24. The MPC8240 FPM or EDO ECC Syndrome Encoding (Data bits 32:63)
Syndrome
Bit
Data Bit
3
2
3
3
3
4
3
5
3
6
3
7
3
8
3
9
4
0
4
1
4
2
4
3
4
4
4
5
4
6
4
7
4
8
4
9
5
0
5
1
5
2
5
3
5
4
5
5
5
6
5
7
5
8
5
9
6
0
6
1
6
2
6
3
0
x
x
x
x
x
x
x
x
1
x
x
x
x x
x
x
x
2
x x x x x x x x x x x x x x x x
x
x
x
x
3
x
x
x
x
x
x
x
x x x x
4
x x x
x x x
x x x
x x x
x x x x
5
x x x x
x x x x x x x x x x x x
6
x x x x x x x x x x x x
x x x x x x x x
7
x x
x x
x x x x
x x x x x x x x
x x x
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 ...