Are Cypress flash devices expected to work if the input signal has overshoot and undershoot?
The maximum allowable overshoot and undershoot of input signals is mentioned in the Absolute Maximum Ratings section of the corresponding datasheet.
For example, the Absolute Maximum Ratings for overshoot and undershoot for the S29GL512T device are:
All pins other than RESET#
You can access the S29GL512T datasheet here.
If the input signal is within the above limits, the flash devices will work without any issues.
But during voltage transitions, the voltage of input signals might go beyond this limit, that is, overshoot might be greater than
VIO/VCC + 0.5 V and undershoot might be lesser than -0.5 V. Cypress flash devices can support such overshoot and undershoot for 20 ns if they are lesser than 2 V (overshoot greater than VCC+2 V and undershoot lesser than -2 V). If either of these voltage levels or the duration exceeds the limit, the device might get damaged.