Problem with SPI normal state BeagleBone Black

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Aug 23, 2018, 8:16:41 AM8/23/18
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I have some problem with spi

I use BeagleBone Black to write eprom by using. after it finish writing EPROM and the EPROM is read by other controller there is no problem

but after I reboot controller (BBB still operate) it can not read data from EPROM after i checked with scope 

I saw that some SPI pin act like a ground that make other controller cannot get the data because they always connected together

right now my solution is just setting the pin mode back to gpio 

so is this a normal state pin of SPI?
is there any solution without swapping pin mode?

I'm using kernel 3.8.13-xenomai-r78 with debian version 7.8 and it occured to me too when i was using the newest image debian version 9.4 


Aug 23, 2018, 9:17:17 AM8/23/18
spi is not really meant to have 2 masters on the same bus.
I am sure you can figure something out using extra gpio pins to tell the beaglebone
when the other master wants access.
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