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Chapter 7 ECC Generation Module (SRAM_ECCV1)
MC9S12ZVM Family Reference Manual Rev. 1.3
240
Freescale Semiconductor
7.3.6
ECC Algorithm
The table below shows the equation for each ECC bit based on the 16 bit data word.
Table 7-11. ECC Calculation
7.3.7
ECC Debug Behavior
For debug purposes, it is possible to read and write the uncorrected use data and the raw ECC value directly
from the memory. For these debug accesses a register interface is available. The debug access is performed
with the lowest priority; other memory accesses must be done before the debug access starts. If a debug
access is requested during an ongoing memory initialization process, then the debug access is performed
if the memory initialization process is done.
If the ECCDRR bit is set, then the automatic single bit ECC error repair function for all read accesses is
disabled. In this case a read access from a system memory location with single bit ECC error will produce
correct data and the single bit ECC error is flagged by the SBEEIF, but the data inside the system memory
are unchanged.
By writing wrong ECC values into the system memory the debug access can be used to force single and
double bit ECC errors to check the software error handling.
It is not possible to set the ECCDW or ECCDR bit if the previous debug access is ongoing (ECCDW or
ECCDR bit active). This ensures that the ECCDD and ECCDE registers contains consistent data. The
software should read out the status of the ECCDW and ECCDR register bit before a new debug access is
requested.
7.3.7.1
ECC Debug Memory Write Access
Writing one to the ECCDW bit performs a debug write access to the memory address defined by register
DPTR. During this access, the raw data DDATA and the ECC value DECC are written directly into the
system memory. If the debug write access is done, the ECCDW register bit is cleared. The debug write
Table 7-10. SRAM_ECC Interrupt Sources
Module Interrupt Sources
Local Enable
Single bit ECC error
ECCIE[SBEEIE]
ECC bit
Use data
ECC[0]
~ ( ^ ( data[15:0] & 0x443F ) )
ECC[1]
~ ( ^ ( data[15:0] & 0x13C7 ) )
ECC[2]
~ ( ^ ( data[15:0] & 0xE1D1 ) )
ECC[3]
~ ( ^ ( data[15:0] & 0xEE60 ) )
ECC[4]
~ ( ^ ( data[15:0] & 0x3E8A ) )
ECC[5]
~ ( ^ ( data[15:0] & 0x993C ) )
Содержание MC9S12ZVM series
Страница 116: ...Chapter 2 Port Integration Module S12ZVMPIMV1 MC9S12ZVM Family Reference Manual Rev 1 3 116 Freescale Semiconductor ...
Страница 242: ...Chapter 7 ECC Generation Module SRAM_ECCV1 MC9S12ZVM Family Reference Manual Rev 1 3 242 Freescale Semiconductor ...
Страница 384: ...Chapter 10 Supply Voltage Sensor BATSV3 MC9S12ZVM Family Reference Manual Rev 1 3 384 Freescale Semiconductor ...
Страница 484: ...Chapter 13 Programmable Trigger Unit PTUV2 MC9S12ZVM Family Reference Manual Rev 1 3 484 Freescale Semiconductor ...
Страница 662: ...Chapter 17 Gate Drive Unit GDUV4 MC9S12ZVM Family Reference Manual Rev 1 3 662 Freescale Semiconductor ...
Страница 684: ...Chapter 18 LIN Physical Layer S12LINPHYV2 MC9S12ZVM Family Reference Manual Rev 1 3 684 Freescale Semiconductor ...
Страница 740: ...Chapter 19 128 KB Flash Module S12ZFTMRZ128K512V2 MC9S12ZVM Family Reference Manual Rev 1 3 740 Freescale Semiconductor ...
Страница 756: ...Appendix A MCU Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 756 Freescale Semiconductor ...
Страница 772: ...Appendix D LINPHY Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 772 Freescale Semiconductor ...
Страница 776: ...Appendix E GDU Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 776 Freescale Semiconductor ...
Страница 788: ...Appendix I MSCAN Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 788 Freescale Semiconductor ...
Страница 790: ...Appendix J Package Information MC9S12ZVM Family Reference Manual Rev 1 3 790 Freescale Semiconductor ...