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Components for being able to access the same SPI Flash with two different external controllers?

Other Parts Discussed in Thread: TMUX1574, SN3257-Q1

In the Application Brief Enabling SPI-Based Flash Memory Expansion by Using Multiplexers in Figure 1, a MUX configuration is shown, where two external controller can be multiplexed to get access to the same SPI Flash device.
However, as of now I could not identify any specific component, which could be used for this Use Case. For example I found this component TS3A27518E-Q1 but based on the typical application shown I would not be sure where the same component could be also used for the use case previously mentioned.

So which would be recommenable components for this use case to be able to access the same SPI Flash with two different external controllers?

  • Hello Marvin,

    For figure 1 on this app note you would need to use a 2:1 4 channel device to use like the picture you are referring too.

    A great option for this is the TMUX1574 and we also have more information on multiplexers in spi applications.

    Please let me know if you need and additional assistance.

    Regards

    Kameron

  • Hello Kameron,

    thank you very much for your fast answer and very helpful recommendation.
    The TMUX1574 really seems to fit here for the Use Case.
    Maybe the SN3257-Q1 would fit even a bit better as the use case will be for an Automotive Use Case?

    The Application example also seems to fit perfectly for the High Level Schematic in Figure 1



    Now the Use Case on our side, however, change more to the High Level Schematic in Figure 2, however not to connect 1 Processor to 2 Flashes, but rather to connect 1 Processor to 1 another Processor or to a Flash, as outlined in the sketch below:




    Would the SN3257-Q1 be applicable also for such a Use Case?

    Regards,
    Marvin

  • Hello Marvin,

    Yes the SN3257-Q1 is a great choice for spi applications. Please check out this FAQ

    In addition this device can pass spi signals to both the flash and processor. The mux should  not be a limiting factor.

    Please let me know if you have any additional questions!

    Regards,

    Kameron