As the datasheet states the VIL value ( Input Low Voltage) value for zz pin or any pin for the device is 0.8V for a 3.3V device. Since the MPN you are mentioning also has a errata associated with it i request you to go through it once in the datasheet. The pin needs to be at Low or High voltage as per the requirement but do not leave the pin as unconnected/ floating as it can lead to errors. Can you once tie the ZZ pin externally to GND and check
To debug your issue can you kindly check and provide us
1) The power up and power down waveform for the device.
2) The wave form for the ZZ pin along with other control signals like WE, CE, OE etc for a read/write operation on the device.
Thank you for your attention.I tried to put the pin zz connect to the ground on the board,the phenomenon is no changed.
The hardware situation determined that the record for power up and power off of the device cannot be got.The ila waveform of the chipscope and the hardware design is followed as below.
When writting data on the device,the right data could be found on dq bus.However the data was still the last writting data on the dq bus when reading.I would feel grateful if you could provide some advices for me.
Thank you very much. The probelem has been solved.The reason for this question is that the version of schematic design is not updated as soon as possible.The product of CYPRESS is good.