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Unable to get Nios-II F going, Nios-II S works fine in same config. (DE2-115 + SDRAM)

Honored Contributor II

Hello All, 

I have a DE2-115 running a Nios-II S(low) with the on board SDRAM (basic config, HELLO WORLD application). 50 Mhz clock, 3ns delay for the ram clock, no FPGA RAM used. 

When I change to Nios-II-F(ast), using the same configuration I am unable to start the CPU (an exception is thrown at startup). 

I wonder what can be the reason ? 

What is a bit strange is that the OpenCore dialog box (Quartus Lite Edition 17.0) does not come up when I download. I know that the Slow CPU does not need the Open Core licence (as it seems), but I thought that the F version did. 


If so, how can I convince Quartus to launch OpenCore upon download of my VHDL project ? 

To be sure there are no hickups in Eclipse, I generate a new program based on the SOPC file generated by QSYS, so I do not use an updated BSP to start from when changing the CPU type. The old configuration cannot pollute the new one. 


The exact error I get is that Nios throws an exception and ends up at Nios2_BREAK() (alt_instruction_exception_entry.c). This after I oblige eclipse to download by overruling the timpmestamp check that is not correct.) Since I generated a brand new file based on a newly generated Sopc file, this also seems very strange. Iam also very sure I download the correct version to my FPGA board. (tried it multiple times) 


Backtracking on the stack, the exception seems to be generated in alt_get_fd.c, getting a descriptor for my Jtag Uart. Very strange because for the -S CPU this works properly ? The exact line is line 79 where is accessed. 

for (i = 0; i < alt_max_fd; i++) 

if (! <= this line 

alt_fd_list[i].dev = dev; 

if (i > alt_max_fd) 

alt_max_fd = i; 



rc = i; 

goto alt_get_fd_exit; 

Is there anybody who got the -F cpu working on an SDRAM config for the DE2-115 in a Quartus lite config? 

Is anybody able to explain what I did wrong or forgot ? 


Thanks for any advice, 



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Honored Contributor II

Dear All, 

My mistake: 

You can select 2 different versions of the .sof file to download to the FPGA. 

The standard version 

The time limited version. 

For the /f cpu you need the time limited version in Q lite. 


And for those of you struggeling with a DE2-115 Nios-II/F. 

I included a Q17.0 archive of my working project. 


Best Regards, 

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