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Newbie yossivideo
Newbie
4,669 Views
Registered: ‎08-04-2010

Spartan 3 and Spartan 6 - Frame Buffer Throughput

Hi,

I'm designing a system that requires video frame buffer that can support 1080p (1920x1080) @60Hz with 24bpp.

In both Video starter kits (for the Spartan 3 and 6) the maximum resolution in the demos is 720p (74.25 MHz pixel rate).

 

Does anybody try to run a frame buffer (VFBC) with speeds of 148.5MHz writing and reading from the same DDR SDRAM?

 

Thanks,

Yossi

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3 Replies
Instructor
Instructor
4,664 Views
Registered: ‎07-21-2009

Re: Spartan 3 and Spartan 6 - Frame Buffer Throughput

You need roughly 373MB/sec bandwidth to your frame buffer

1920 * 1080 * 60FPS * 3Bytes/pixel

If you want to read and write concurrently, double that to around 750MB/sec.

 

S6 -2 speed grade supports DDR-667.  You'll need a 16bit wide DRAM to provide enough bandwidth (plus headroom) for a full duplex frame buffer.  If read and write are non-overlapping, you could get by with a 1 byte wide DRAM.

 

How is your video coming on-chip?  A -2 speed grade S6 doesn't have the ISERDES bit rate required for 1920x1080p/60 TMDS (e.g. DVI or HDMI).  I haven't checked on -3 speed grade vs. 1080p/60.

 

- Bob Elkind

SIGNATURE:
README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

Summary:
1. Read the manual or user guide. Have you read the manual? Can you find the manual?
2. Search the forums (and search the web) for similar topics.
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Newbie yossivideo
Newbie
4,659 Views
Registered: ‎08-04-2010

Re: Spartan 3 and Spartan 6 - Frame Buffer Throughput

Bob,

 

Thank you.

The video is streamed as 24bit, HS, VS, DE & CLK.

When you say DDR-667 you mean DDR2 @ 333MHz?

 

Where did you got the info that the "S6 -2 speed grade supports DDR-667"? does -3 will be even better?

 

Do you think that if I'll implement 2 memory controllers, one with 16 bit DDR and the other 8 (or 16) bits DDR i'll be 100% safe or it'll be enough to use one 16 bit 400 MHz DDR2 or DDR3?

 

Cheers,

Yossi

 

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Instructor
Instructor
4,651 Views
Registered: ‎07-21-2009

Re: Spartan 3 and Spartan 6 - Frame Buffer Throughput

When you say DDR-667 you mean DDR2 @ 333MHz?

Yes, I meant to write DDR2-667, which uses a 333MHz clock with DDR data signaling

Where did you got the info that the "S6 -2 speed grade supports DDR-667?

Check the datasheet, doc DS162.  Requires extended VCCint for DDR2-667 support on -2 speed grade.

does -3 will be even better?

-3 speed grade supports up to DDR2-800, with extended VCCint

Do you think that if I'll implement 2 memory controllers, one with 16 bit DDR and the other 8 (or 16) bits DDR i'll be 100% safe or it'll be enough to use one 16 bit 400 MHz DDR2 or DDR3?

You haven't described your design requirements sufficiently to give you an authoritative answer.  You should do the calculations yourself, it's a pretty simple decision.  First figure out how much concurrent data bandwidth you need.  If one memory controller meets your needs, you shouldn't attempt to use two -- this will add considerable complexity to your design.

- Bob

SIGNATURE:
README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

Summary:
1. Read the manual or user guide. Have you read the manual? Can you find the manual?
2. Search the forums (and search the web) for similar topics.
3. Do not post the same question on multiple forums.
4. Do not post a new topic or question on someone else's thread, start a new thread!
5. Students: Copying code is not the same as learning to design.
6 "It does not work" is not a question which can be answered. Provide useful details (with webpage, datasheet links, please).
7. You are not charged extra fees for comments in your code.
8. I am not paid for forum posts. If I write a good post, then I have been good for nothing.
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