Altera DE2 SDRAM Contoller

Question

Hi;

I have confusion about sdram controller. I use Altera DE 2 board with Cyclone II and I want to use the external memory, sdram (8MB) to store image. As I know, we can use SOPC builder with Nios to make the sdram controller and I have try it by follow the steps in Using the SDRAM Memory on Altera's DE2 Board with VHDL Design document. But, to running the application program I need to write required program in NIOS ii Assembly language or in c. Is it this is the rules when we use SOPC builder? Can I use VHDL to run the application program after make the SOPC setting for sdram?

Anyone please told me the right way..:confused:thank you

altera_forum · Answer

What's the problem with sdram? If you correctly configured the sdram controller in sopc builder you use it in Nios application code like any other memory.

Did you read the sopc builder tutorial? I think it includes sdram and this will guide you step by step from scratch to a simple working system.

altera_forum · Answer

Hi Cris72,

Yes, I understand the step of sopc builder and I have done it. I'm stuck at the last step,where need to make another program in c language for running the nios. I not familiar with c and I try to avoid it.

My question is can I just running the nios using vhdl code? My main program is to process pixels that stored in sdram in vhdl. Thanks for reply

altera_forum · Answer

VHDL is a HDL (Hardware Description Language): it is intended to describe digital circuits which Quartus will eventually synthesize into fpga. Nios is part of these circuits, together with all sopc builder stuff and external logic. Anyway, after the fpga configuration, Nios is actually a 'real' microprocessor, so you are supposed to program it with a sequential language: C, assembler or whatever the dev tools provide. You can't program Nios with VHDL. Although both VHDL and C can virtually be used to perform the same operation, they apply to two different worlds and behave very differently.

altera_forum · Answer

--- Quote Start ---

Anyway, after the fpga configuration, Nios is actually a 'real' microprocessor, so you are supposed to program it with a sequential language: C, assembler or whatever the dev tools provide. You can't program Nios with VHDL. Although both VHDL and C can virtually be used to perform the same operation, they apply to two different worlds and behave very differently.

--- Quote End ---

Hi Cris72,

Okay, so now I need to program the nios (sdram controller) with c language. Then, my main program (some mathematical operation to the pixels) is write in vhdl. How can I connect the nios (sdram controller) with the main program (vhdl)? I can't figure it out..I'm new with nios,please advise me.

altera_forum · Answer

There are different solutions, but I think all of them are not easy for a beginner.

1. Write your pixel elaboration algorythm in C and use Nios

2. Implement an Avalon MM master in your VHDL module, so you can directly access sdram; but this makes Nios pointless

3. Wrap your vhdl code into a Nios custom instruction

4. Use Nios to transfer data to vhdl module (possibly using dma) and then get it after it has been elaborated. In this case you must provide an Avalon slave MM or ST interface to your vhdl module.

The first one is the easiest, but from what you said I guess you don't want to use it.

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Altera DE2 SDRAM Contoller

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