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Valued Contributor III
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2 masters accessing a Slave

Hi , 

 

I am a nios newbie. We have a slave that has 16 byte address space, 

Since we do word access, we have used 2 address lines for slave. 

Nios and another master(created by us) access the slave. Does our 

master need to have more than 2 address lines? 

 

Our peripheral is automatically assigned address space 0x00 to 0x0F by 

SOPC builder and we get a message saying it clashes with address space of flash. 

Since we have locked the flash address space to start from 0x00, we 

can't understand why our slave is assigned the same address range ? 

 

does our master have to supply a 32 bit address ? 

 

Kindly help... 

 

 

regards 

karthik
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Valued Contributor III
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Hi karthik, 

 

> Since we do word access, we have used 2 address lines for slave. 

 

Ok ... it's a 32-bit slave. 

 

> Does our master need to have more than 2 address lines? 

 

Yes, you&#39;ll need at least 4 for a 16-byte slave. From the Avalon Interface Specification:<div class='quotetop'>QUOTE </div> 

--- Quote Start ---  

Master addresses represent byte addresses, regardless of the data-width of the master port.[/b] 

--- Quote End ---  

 

 

> we get a message saying it clashes with address space of flash 

 

Change the address to an unused memory region. 

 

> Since we have locked the flash address space to start from 0x00, we 

> can&#39;t understand why our slave is assigned the same address range ? 

 

I just upgraded to 5.1 so I can&#39;t comment on this. I don&#39;t recall any problems 

in earlier versions. You can change the address in the mean time. 

 

Regards, 

--Scott
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Valued Contributor III
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<div class='quotetop'>QUOTE </div> 

--- Quote Start ---  

does our master have to supply a 32 bit address ?[/b] 

--- Quote End ---  

 

 

I don&#39;t think so, Nios has the functionalities of both Native Address Alignment and Dynamic Address Alignment, you can get the detail informaiton in datasheet Avalon Interface Specification. 

 

 

David
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