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Dat Tran
Senior II
February 19, 2018
Question

SPWF04SA SPI MISO driven when not selected

  • February 19, 2018
  • 1 reply
  • 665 views
Posted on February 19, 2018 at 16:06

Hi, 

In our testing of the SPWF04SA module in SPI mode, we've noticed that even when nCS is held high, the module is actively driving MISO low. Additionally, with nCS still high, when we clock SCK for another bus device, the SPWF04SA will actually send apparently valid data out on the MISO pin. MISO should never be driven by the SPWF04SA when it isn't selected. This interferes with other SPI devices on the same bus.

We've confirmed this by the fact that other bus devices again work correctly when holding the SPWF04SA in reset.

Thanks

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    1 reply

    Dat Tran
    Dat TranAuthor
    Senior II
    March 12, 2018
    Posted on March 12, 2018 at 19:19

    Any idea, please?