nRF9E5 design with 25AA320- EEPROM loses data in rare circumstances

[Rima]

Hi,

In our design we are using 25AA320 with nRF9E5 . It seems in some random conditions the EEPROM loses data and the application won't run until EEPROM is reprogramed again. It seems like it is happening if the board is resting more often. Are there any conditions hardware/software that can cause the whole/part of EEPROM be erased? We have many different designs with no problem and one that may reset more often we see this issue.

Any help or suggestion is appreciated!

Thanks,

Rima

[Rima]

Rima said:

it is happening if the board is resting more often

resetting more often!

[ketiljo]

If the nRF9E5 don't have access to the PROG pin of the EEPROM, it's not likely that the nRF9E5 can alter the content of the EEPROM. Do you have control of the logic level of the PROG pin?

[Rima]

Yes, we use SPI interface to write and read couple of bytes at the end of EEPROM. The write is done in specific condition and not normal operation and read is always done at board power up.

[ketiljo]

Do you have pull down and pull up resistors on the lines to make sure you always have a defined logic levels? Typically pull up on CS and HOLD. Make sure WP is not floating. 

[Rima]

Yes, I think we have proper pull ups/downs. We used the same design in other boards with no issue. The one difference with our other designs is the serial connection with another processor(P01, P02). I don't know how that can cause this issue.