Chapter 15 Error Correction Status Module (ECSM)
MPC5602P Microcontroller Reference Manual, Rev. 4
296
Freescale Semiconductor
15.4.2.18 RAM ECC Syndrome Register (RESR)
The RESR is an 8-bit register for capturing the error syndrome of the last properly enabled ECC event in
the RAM memory. Depending on the state of the ECC Configuration Register, an ECC event in the RAM
causes the address, attributes and data associated with the access to be loaded into the REAR, RESR,
REMR, REAT and REDR registers, and the appropriate flag (R1BC or RNCE) in the ECC Status Register
to be asserted.
This register can only be read from the IPS programming model; any attempted write is ignored.
Note:
associates the upper 7 bits of the ECC syndrome with the exact data bit in error for single-bit correctable
codewords. This table follows the bit vectoring notation where the LSB=0. Note that the syndrome value of 0x0001 implies
no error condition but this value is not readable when the PRESR is read for the no error case.
Address: Base + 0x0065
Access: User read-only
0
1
2
3
4
5
6
7
R
RESR[7:0]
W
Reset
—
—
—
—
—
—
—
—
Figure 15-17. RAM ECC Syndrome Register (RESR)
Table 15-18. RESR field descriptions
Name
Description
0-7
RESR[7:0]
RAM ECC Syndrome Register
This 8-bit syndrome field includes 6 bits of Hamming decoded parity plus an odd-parity bit for the
entire 39-bit (32-bit data + 7 ECC) code word. The upper 7 bits of the syndrome specify the exact bit
position in error for single-bit correctable codewords, and the combination of a non-zero 7-bit
syndrome plus overall incorrect parity bit signal a multi-bit, non-correctable error.
For correctable single-bit errors, the mapping shown in
associates the upper 7 bits of the
syndrome with the data bit in error.
Table 15-19. RAM syndrome mapping for single-bit correctable errors
RESR[7:0]
Data Bit in Error
0x00
ECC ODD[0]
0x01
No Error
0x02
ECC ODD[1]
0x04
ECC ODD[2]
0x06
DATA ODD BANK[31]
0x08
ECC ODD[3]
0x0A
DATA ODD BANK[30]
0x0C
DATA ODD BANK[29]
0x0E
DATA ODD BANK[28]
0x10
ECC ODD[4]