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using spi core

Altera_Forum
Honored Contributor II
804 Views

I want to use the spi core for adc peripheral AD9253. It has bidirectional SDIO. but spi core in nios has miso and mosi. so how do i tackle this. i want to read and write to the adc registers.

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3 Replies
Altera_Forum
Honored Contributor II
106 Views

A simple solution is driving SDIO in open collector mode using a tristate i/o buffer and a pull-up resistor. 

MOSI is connected to the active low buffer enable port, while the i/o buffer input is hardwired to gnd. 

MISO is connected to the same i/o pin. 

This way you simply put ones in the spi tx register for the bits you are supposed to receive.
Altera_Forum
Honored Contributor II
106 Views

 

--- Quote Start ---  

A simple solution is driving SDIO in open collector mode using a tristate i/o buffer and a pull-up resistor. 

MOSI is connected to the active low buffer enable port, while the i/o buffer input is hardwired to gnd. 

MISO is connected to the same i/o pin. 

This way you simply put ones in the spi tx register for the bits you are supposed to receive. 

--- Quote End ---  

 

Hello, sherindeena! 

Did You try to make it this way? 

Here are another replies to this question:  

http://www.alteraforum.com/forum/showthread.php?t=26838 

http://www.alteraforum.com/forum/showthread.php?t=38228 

Which one is correct?  

I am interested because I am about to make the similar connection.
Altera_Forum
Honored Contributor II
106 Views

 

--- Quote Start ---  

Hello, sherindeena! 

Did You try to make it this way? 

Here are another replies to this question:  

http://www.alteraforum.com/forum/showthread.php?t=26838 

http://www.alteraforum.com/forum/showthread.php?t=38228 

Which one is correct?  

I am interested because I am about to make the similar connection. 

--- Quote End ---  

 

 

i just left the unused line unconnected. i didnt read back the registers.
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