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difference between spidev1.0 and spidev1.1
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difference between spidev1.0 and spidev1.1

by rifo on Fri Jun 24, 2016 12:03 pm

Hello

Can you please tell me the difference between spidev1.0 and spidev1.1?

In the linux kernel documentation https://www.kernel.org/doc/Documentation/spi/spidev it says that

chipselect C on bus B, you should see: /dev/spidevB.C ..


Does this then mean that there are 2 chipselect signals on BBB, e.g P9_38 is SPI1_CSO where is then SPI1_CS1

I am kind of confused, I would be happy if you can help me.

thanks
rifo
rifo
 
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Re: difference between spidev1.0 and spidev1.1

by drewfustini on Fri Jun 24, 2016 9:34 pm

Yes, the first number is the bus and the second number is the chipselect.

spidev1.0 would be bus 1, chip select 0.

For more info:
https://learn.adafruit.com/setting-up-i ... -black/spi

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Re: difference between spidev1.0 and spidev1.1

by rifo on Sat Jun 25, 2016 3:21 am

Hello,

Thanks for your answer. Then I will check the sitara processor's datasheet to see which pin is being used as CS1.
Has anybody came across any examples/project that makes use of spidev1.1 ?

thank
rifo
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Re: difference between spidev1.0 and spidev1.1

by drewfustini on Sun Jun 26, 2016 5:57 am

This project uses both chipselects, CS0 & CS1, on SPI1:
Adventures in BeagleBone Black Device Overlays and SPI
It’s important to recognize that the above spidev devices were created when we added our device tree overlay, and that the notation is /dev/spidevMASTER.CHIPSELECT_REG. In this case MASTER is SPI1, which is in the filesystem as spidev2. The cs0 line for SPI1 is to Slot 1, and the cs1 line for SPI1 is to Slot 2.

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