TMS320F28388D: zone 1 of the flash memory is locked

Hi Team, 

Good day. I am posting this inquiry on behalf of the customer.

"We are writing to report an issue we are experiencing with programming the flash memory of the TMS320F28388D microcontroller on a custom board. The custom board is similar to the TMDSCNCD28388D Control Card but has a different form factor.

We have already produced a successful batch of this custom board with no issues. Microcontroller’s lot number on this first batch was F28388DZWTS $7A-21C2H1W G1.

 However, we recently launched a new batch of the same custom board, and we are having problems programming the devices. In this new batch, the TMDSCNCD28388D microcontroller has the F28388DZWTS $7A-14A56GW G1lot number.

 We have compared units from the first and second batches and found no hardware or design issues (since the first batch works well, and the design is very similar to the TMDSCNCD28388D reference, using an FTDI FT2232HL programmed as an XDS100v2 emulator).

 We believe that in this batch, the microcontrollers have arrived with the zone 1 of memory locked, and we do not know the password to unlock it.

The following are the messages we receive when attempting to erase the flash memory using the UNIFLASH tool:

[17/4/2023 10:38:13] [INFO] C28xx_CPU1: Warning: Failed unlocking device (zone 1) after reset.

[17/4/2023 10:38:24] [ERROR] C28xx_CPU1: Flash Programmer: Error erasing Sector 0. FMSTAT value = 1040. Operation Cancelled (0).

[17/4/2023 10:38:24] [ERROR] C28xx_CPU1: Flash Programmer: Error erasing flash. Please check if the device is locked.

When attempting to unlock with the default password (using UNIFLASH), we are informed that the device is locked:

[17/4/2023 14:25:31] [INFO] C28xx_CPU1: Performing Security Operation...

[17/4/2023 14:25:31] [INFO] C28xx_CPU1: Calculated Link Pointer Offset: 0x20

[17/4/2023 14:25:31] [INFO] C28xx_CPU1: Unlocking device...

[17/4/2023 14:25:31] [INFO] C28xx_CPU1: Lock status: 1

[17/4/2023 14:25:31] [ERROR] C28xx_CPU1: Error unlocking device. Device still locked. Please recheck the entered password.

When attempting to write to memory to program, we are told that the memory map is not suitable. This occurs with both UNIFLASH and CODE COMPOSER STUDIO.

[17/4/2023 18:04:52] [ERROR] C28xx_CPU1: File Loader: Verification failed: Values at address 0x008000@Program do not match Please verify target memory and memory map.

Additionally, when performing all these tasks on a card from the first production run, there are no errors.

We have attached a report with additional conclusions from our software department.

 Can you confirm if the zone 1 of the flash memory is locked based on this information? If not, how can we confirm it? Is there any way to unlock it without knowing the passwords?

 Thank you in advance for your assistance."

Please help to advise. Thank you for extending your support.

Kind regards, 

Marvin