Under-/Overvoltage Conditions During Memory Write Operations

Question:
What happens if there are under-/overvoltage conditions during memory write operations?
Answer:
A write operation out of operating voltage can lead to an unpredictable state of the flash cell (e.g. a brown out, see the notes below).

To avoid an unpredictable behavior, writing should be disabled (call Fee_SuspendWrites) out of operating voltage. The Fee stays in current state and processes the job from this state, in case that the user calls Fee_ResumeWrites again. The Fee job will not be canceled. If the Fls driver also supports a suspend writes functionality, also call the corresponding function from your application. If not, a possibility is not to execute Fls_MainFunction in situations out of operating voltage.
 
Note:
  • This behavior is applicable/relevant for Standard Fee and Small Sector Fee.
  • Brown out:
    • A voltage drop can impact write operations. A residual electric charge may not be sufficient to toggle the bits persistently (marginal data); the bit may toggle back later without notice.
    • If you read this data later, it is not predictable what you get, either correct data will be returned or an ECC error will be recognized. It is also possible that you get wrong data and no ECC error.


Article ID: 1085
Last updated: 2020-04-17
Revision: 3
MICROSAR and DaVinci -> Troubleshooting -> MICROSAR MEM -> Under-/Overvoltage Conditions During Memory Write Operations
https://kb.vector.com/entry/1085/