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Using several SPIs in parallel

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savage67

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Hi everyone,

I am aiming to connect several SPI devices in parallel manner. To achieve that, as i know less, some pull-up or pull-down resistor must be use in mosi, miso and ss pins. Could ypu please explain me what is the purpose of using them and which pins(mosi miso sck ss) actualy need that?

Regards.
 

Multiple SPI Devices

Amicus18 to Multiple SPI slaves.png

Daisy chain SPI configuration‎:


500px-SPI_three_slaves_daisy_chained.svg.png
 
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    FvM

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Thanks for the configuration info but main problem is using pull-up, pull-down resistor. Which pins(mosi miso sck ss) actualy need that? What is the purpose of using them.
Regards.
 

You didn't tell about the intended topology. I would primarly think of a master to multiple slaves setup, as shown in the above post. You'll notice that it doesn't need any pull-up or pull-down resistors.
 

Topology : one master to multi slaves.
I intend to use parallel connection so i will use different SS pins for each SPI device. Connecting pins without pull resistors cause any bus-fight? I am not sure about that. I guess the pictures above for giving a basic idea.

Are you sure that any pull resistor is not needed?
Thanks.
 

All SPI signals are ususally driven by regular push-pull outputs and don't need pull-up/-down resistors. The slave MISO outputs must be tri-stated for all unselected devices.
 
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