Error Checking and Correction
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
12-23
single-bit error registers can be programmed so that minor memory faults are corrected and
ignored, but a catastrophic memory failure generates an interrupt.
For writes smaller than the bus width (32 or16 bits), the DDR memory controller performs a read
from system memory of the address for the write (checking for errors), and merges the write data
with the data read from memory. Then, a new ECC code is generated for the merged data. The
data and ECC code is then written to memory. If a multi-bit error is detected on the read, the
transaction completes the read-modify-write to keep the DDR memory controller from hanging.
However, the corrupt data is masked on the write, so the original contents in SDRAM remain
unchanged. The syndrome encoding for the ECC code are shown in Table 12-10 and Table
12-11.
Table 12-10. DDR SDRAM ECC Syndrome Encoding
Data
Bit
Syndrome Bit
Data
Bit
Syndrome Bit
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
•
•
•
16
•
•
•
1
•
•
•
17
•
•
•
2
•
•
•
18
•
•
•
3
•
•
•
19
•
•
•
4
•
•
•
20
•
•
•
5
•
•
•
21
•
•
•
6
•
•
•
22
•
•
•
•
•
7
•
•
•
23
•
•
•
•
•
8
•
•
•
24
•
•
•
9
•
•
•
25
•
•
•
10
•
•
•
26
•
•
•
11
•
•
•
26
•
•
•
12
•
•
•
28
•
•
•
13
•
•
•
29
•
•
•
14
•
•
•
30
•
•
•
15
•
•
•
•
•
31
•
•
•
Table 12-11. DDR SDRAM ECC Syndrome Encoding (Check Bits)
Check
Bit
Syndrome Bit
0
1
2
3
4
5
6
7
0
•
1
•
2
•
3
•
4
•
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...