TMS320F28P550SJ: NVM Erase at SW reset

Hi Srikanth,

The C2000Ware EEPROM Ping Pong example does not include a built-in mechanism to skip the erase when valid data already exists in the bank. You'll need to add a custom validation check before the erase call inside EEPROM_Config_Check to conditionally skip it.

Recommended Approach: Magic Number / Signature Check

On C2000 flash, an erase sets all bits to 1 (i.e., erased flash reads as 0xFFFF). You can exploit this to detect whether a bank already contains valid data:

1. Reserve a known location in each NVM bank for a "magic number" or signature (e.g., 0xA5A5 or any value that is not 0xFFFF).

2. Before calling the erase function in EEPROM_Config_Check, read that location. If the signature is present and valid, skip the erase — the bank already has initialized data.

3. Only erase if the signature location reads 0xFFFF (blank/erased) or contains an unexpected value (corrupted data).

Pseudocode example:

// At the start of EEPROM_Config_Check, before the erase call:
uint16_t signature = *(volatile uint16_t *)EEPROM_BANK_SIGNATURE_ADDR;

if (signature == EEPROM_VALID_SIGNATURE)
{
// Valid data exists — skip erase, proceed to normal operation
return;
}

// Signature not found — first-time init or corrupted bank
// Proceed with erase and then write the signature after initialization
Fapi_issueAsyncCommandWithAddress(Fapi_EraseBank, ...);
// ... after erase and initial data programming ...
// Program the signature to mark the bank as initialized

4. Write the signature as the last step after a successful erase + initial data programming. This ensures that if power is lost mid-erase, the signature won't be present and the erase will correctly re-run on the next boot.

Why This Works

• Fapi_doBlankCheck() checks if flash main array equals 0xFFFF — it confirms whether a region is erased. You could also use this API call instead of (or in addition to) a magic number to determine bank state.
• The Flash API does not track erase counts or initialization state automatically — this must be managed in your application code.

Additional Consideration

You can also use Fapi_doBlankCheck() directly on the data region of the bank. If it returns that the bank is not blank, you know data has been programmed and you can skip the erase. However, a dedicated signature/magic number is more robust because it distinguishes between "valid initialized data" and "partially written/corrupted data."

Best Regards,

Zackary Fleenor