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AM2431: having a OSPI part with DQS pin and a QSPI part on the OSPI interface

lance Forman
Intellectual 280 points
Part Number: AM2431

We are considering having two devices on the OSPI interface.

One of the devices would be an OSPI NOR flash part that has DQS support.

If I connect the DQS signal between the TI part and the OSPI NOR flash part and then also have a 2nd QSPI part on a different CS, would that be an acceptable configuration.

The reason I ask is in the cases were I am using the QSPI part  wouldn't the DQS signal be inactive. If that is the case would that cause an issue in the read timing for the TI part?

  • 0
    TI__Expert 7630 points

    Hi Iance,

    This is a valid configuration but there are a few things that have to be taken in account when having more than one device attached to OSPI.

    Both devices share the same OSPI0_CLK signal, so if it is not buffered or routed carefully there might be reflections from the far end of the branch. These reflections might look like glitches that overclock the OSPI.

    Also, assuming there is no issue with the OSPI0_CLK signal integrity, then you will have to choose which device you want to run at maximum speed. In this case, the device that has the DQS signal connected to the DQS pin of the processor will be able to reach max speed, but the other device would be limited to using the internal clock only. 

    Best,

    Daniel