Nios® II Embedded Design Suite (EDS)
Support for Embedded Development Tools, Processors (SoCs and Nios® II processor), Embedded Development Suites (EDSs), Boot and Configuration, Operating Systems, C and C++
Intel Support hours are Monday-Fridays, 8am-5pm PST, except Holidays. Thanks to our community members who provide support during our down time or before we get to your questions. We appreciate you!

Need Forum Guidance? Click here
Search our FPGA Knowledge Articles here.
12435 Discussions

Nios II Qsys Simple Dual Port Memory

Honored Contributor II

Hi all, 



I'm trying to set up a small Simple Dual Port Memory in qsys such that I can write to the memory block from the Nios II processor and read from it externally. 


I've set this up successfully using the internal memory module and then exported the second Avalon port. Unfortunately, I need 32 bit data externally which means that two M9K memory blocks are required even though the memory is small as it uses a full dual port rather than simple dual port mode. 


I can set up the memory block fine using MegaWizard but I can't find a way of doing this from qsys. I'm guessing I'm going to have to write my own module to sort this but if there is way of doing this directly I would love to know. 


Cheers, Colin
0 Kudos
2 Replies
Honored Contributor II

I think Qsys lets you select 'single clock mode' - does that let it use 'simple dual port mode' ? 

We are currently fighting quartos 9.1 to get single clock mode working for memory that is tightly coupled to a nios cpu data port in order for OLD_DATA to be honoured.
Honored Contributor II

Thanks for the reply. 


No, single clock mode doesn't help out. I've been using it already. 


For it to be implemented, there would need to be a method which indicates which port in read only and which port is write only and currently there isn't any.