Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public

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5.3.6.9.7. DQS Error

This error is reported in the scenario in which the PHY detects that the number of DQS pulses is lower than the number of read words. In this case, the DQS error bit is set in the last operation status register/descriptor and it is possible that the data stream transferred from the NAND Flash device gets corrupted and can trigger further error conditions. The DQS error can be detected for both data transfer and control sequences.

Under this error condition, the NAND Flash controller sets the DQS error and Fail flags in the last operation status register/descriptor. In CDMA mode, if the cont_on_err field in the device_ctrl (0x0430) register is cleared, then the following descriptors are dropped from execution. In the opposite case, the NAND Flash controller continues the command execution.

If the NAND Flash controller detects the dqs error for the device read status command sequence (used to probe the device status), the data read should be ignored and the controller should mark the device as busy.

Under DQS error condition, the host should reset the PHY (dll_rst_n or rst_n) to clear dqs_underrun or dqs_overrun flags and clear the read data pointers.