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Observer 148128
Observer
4,086 Views
Registered: ‎05-25-2014

SPI I/O

Hi guys, 

I have specific question about SPI driver. Is there any easy way to controll direction of MISO/MOSI pin according to extended SPI standart with SDIO pin exchanging function of MISO and MOSI ? From ARM I got 3 signals for both miso and mosi, so I hope there is some easy way how to drive _t signal without mode change, but I still sannot find it. 

Anyone can help me ? 

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2 Replies
Adventurer
Adventurer
4,065 Views
Registered: ‎05-29-2015

Re: SPI I/O

Take a look at this thread: https://forums.xilinx.com/t5/Welcome-Join/adc-3-pin-spi/m-p/687805/highlight/true#M34851

 

I was able to use this technique on the microzed to talk to a 3-wire ADC slave. I used an AXI-GPIO module to control the tristate flag of the IOBUF primitive. I couldn't find an easy way to do 3-wire SPI in Linux, I'm not sure if the Linux SPI kernel module supports it properly, I could be wrong though. Using a GPIO to control the IOBUF was way easier, in my opinion.

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Observer 148128
Observer
3,970 Views
Registered: ‎05-25-2014

Re: SPI I/O

driving SPI this way is easy, but I work with bare metal (ARM core) and I hope that there is way how to drive those pins especially when there is direction driving pin.
I think that this is just sw library driver problem...
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