TMS570LC4357-EP: ESM2 error while debugging.

Hi Deepak,

1. Root Cause:

• The error is caused by speculative instruction fetches by the CPU
• CPU may attempt to read from a random flash address/ RAM address, generating an uncorrectable ECC error.

2. Behavior:

• The CPU discards the speculatively fetched data and doesn't generate an abort
• However, the memory read still triggers the CPU event signal that tells the ESM there was an uncorrectable flash error
• This results in the ESM2 error being triggered

3. Solution Options:

4. MPU Configuration:

   • You can prevent this error by configuring the MPU to set unused flash regions as "No Access"
   • When the MPU blocks access to unused regions, the CPU can't perform speculative fetches from those areas, preventing the ESM2 error

5. ECC Programming:

   • Ensure proper ECC values are programmed for all flash memory spaces that might be accessed
   • The ECC values for all flash memory space (Flash banks 0 through 6) must be properly programmed before program/data can be read

6. Important Notes:

• This is a known behavior related to the CPU's speculative fetch mechanism
• The error occurs because the speculative fetch attempts to access flash regions with invalid or unprogrammed ECC values
• Group 2 errors (like this one) will always trigger the nERROR pin as they cannot be disabled.

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Thanks & regards,
Jagadish.