Nios® V/II Embedded Design Suite (EDS)
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Strange DMA Transfer

Honored Contributor II

Hello, everyone. I'm the one of engineers to struggle with NIOS2. 


I want to use DMA in 16bit mode. 

The following data is transfered from main memory(SDRAM in my kit) to peripheral. 


DATA: 0000h 01E0h D33Ah ... (continued) 


Next image describes well.  

wave form (

But, the first data(0000h) appears during 4 cycles and next data(01E0h) appears two times again.  

I cann't understand that situation. 


I tried to use DMA-transfer from main memory(SDRAM in my kit) to the same(SDRAM in my kit) in 16bit mode. 

And I experienced the same case. I think, DMA may have problem. 



At the end of Develpment of my product, I have been much anxious about the problem. 

Please, help me, Nios Users and ALTERA ! 

Good luck to every Nios Users.
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Honored Contributor II

I just tried the experiment of transferring data to and from SDRAM in 16-bit mode (for a 32-bit SDRAM) and it seems to work fine. 


Can you post your code which does the 16-bit SDRAM transfer?
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