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A comment on SPI: The serial peripheral interface [video]. Parent comment

Re:SPI: The serial peripheral interface [video] by MisterTea on Monday November 22, 2021 @02:10PM (#29310389)
Chip selects are optional. You can daily chain multiple spi devices and push the data out in a contiguous block. All the chip selects are tied together and only one cs line is used from the cpu.
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Re:SPI: The serial peripheral interface [video] by duskwuff on Monday November 22, 2021 @04:49PM (#29311947)
> You can daily chain multiple spi devices

For some simple SPI devices, sometimes. Many SPI devices, especially more complex ones, won't let you shift data through the device without attempting to interpret it.

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Re:SPI: The serial peripheral interface [video] by monocasa on Monday November 22, 2021 @04:56PM (#29312015)
Or will shift out something completely different, like the response to the last command they received, just FFs so you can three wire in the general case, or even just garbage.
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Re:SPI: The serial peripheral interface [video] by flyingcircus3 on Monday November 22, 2021 @04:56PM (#29312008)
Flash memory devices use the CS line as an integral part of the protocol. It is definitely not optional.
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