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Altera_Forum's avatar
Altera_Forum
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16 years ago

bursts with NIOS II and avalon-mm clock crossing bridge

My prob.: I have to store small data at high speed at the ddr ram(up to 20-160 bytes of data every 100µs).

So maybe I need bursts. Just have to be fast when I write. The reading time doesnt bug me at all.

Now my question: Does the burst support of the avalon-mm clock crossing bridge help me? Do I have bursts at all when I use the IOWR Macro?

I would use a burst length of 8(Whis would fit best for my application).

I use a NIOS II/F cpu with 2k inst. cache and 512bytes data cache. d-ram and i-ram @ on-chip memory. Got connection to 2 DDR2 SDRAM HIGH Performance Controllers over 2 Avalon-MM Clock Crossing Bridnges for storing datas. Got a Stratix III device.

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  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    You won't have bursts using the IOWR macro because it does a single write operation. To have bursts you need to either use a DMA engine that supports bursts, or have the CPU write to its data cache (using traditional pointers) and force it to dump the cache when finished.