Intefacing SDRAM to XMEGA devices.

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I know,it looks like a noob question.

That's perhaps because I'm a noob regarding SDRAM, but I RTFM, for Xmega A core (doc8077 IIRC) and for ATxmega64A1/128A1 et alter, and I only found a funny note on page 48 on the first.

Then I googled Atmel web in search for EIB datasheet, and I couldn't find anything. Thus I decided to raise my pray to this wisdom pool.

Can someone help me a little bit?

Thank you very much.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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EBI -- External Bus Interface. From the 64A1 datasheet

Quote:
7.7 EBI - External Bus Interface
• Supports SRAM up to
– 512 KB using 2-port EBI
– 16 MB using 3-port EBI
• Supports SDRAM up to
– 128 Mbit using 3-port EBI (4-bit wide)
• Simultaneous support of SRAM and SDRAM
• Software configurable Chip Selects
• Software configurable Wait State insertion
The External Bus Interface (EBI) makes it possible to access external memory devices. The XMEGA A1 has 3 ports dedicated to the EBI, making it suited to interface external SRAM, SDRAM, and peripherals such as LCD displays or other memory mapped devices.

But I see what you mean--DOC8077 leaves a lot out. ;)

Ha! Found it with a search for EBI on Atmel's site:
http://www.atmel.com/dyn/general...

Quote:
Application Note AVR1312: Using the XMEGA External Bus Interface Application Note (10 pages, revision A, updated 2/08)
This application note describes the basic functionality of the XMEGA EBI with code examples to get up and running quickly. A driver interface written in C is included as well.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Right now, I feel that I'm only capable to do the pinout and routing, and I'm not even shure that I can do that (because I'm a noob with SDRAM). At least, by the end of the ATsmega 64A1 datasheet is a pinout description for SDRAM that could help.

But how to handle it and how to control refresh and other issues is still a mistery to me. As how to setup the control registers for the EIB.

Well, perhaps I should continue working on some idea about this, try to find suitable SDRAM's IC's for this purpose, and see if I'm capable to wire a little dev board with plenty of SDRAM support for the beast.

BTW, some suggestions about which SDRAM's IC to use?

Thanks again.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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That document and the sample code look quite comprehensive to me.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Well, in the meantime, I found this memory IC suitable: K4S280432K-U from Samsung.

I will try to dig further on this issue.

BTW, Lee, which sample code do you mean?

Thanks.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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Ok, finally I found this link:

http://www.atmel.com/dyn/product...

where there is a doc and sample code to work with EIB. Informative, at least.

Thanks again.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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Didn't you click on my link above? ;)

I scanned through the app note and looked at a bit of the sample code, and thought it was well done for a target audience of experienced AVR/external S[D]RAM newbies like you and me.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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There is also another interesting appnote about C programming style for this beasts. That remember me much of what I learned from AT91SAM7S. The same way and style, that means a lot of 'premade drivers' that eases too much hard initialization. Also the set bit register, clear bit register and toggle bit register for ports looks like the ones used with ARM's architectures.

I didn't see your link. Had you edited it? Its time to go to the ophtalmologist.;)

It seems that Atmel had done a good job. I also have the new version of IAR at my job's PC. Perhaps it's time to order few samples and do some dev board.

Thanks.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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well i am working same "EBI" but for SRAM and facing some problems with colpilers i have pro version of ICC and kickstart of IAR,
which compiler r u using?
in IAR i get *.r90 lib file missing errs and if i dnt use ant lib it wont go in debug mode :?: .

Any idea what may b wrong...

i have assembled hw its ok..trackes etc
am using "bs62lv4000" 512k x 8bit SRAM.