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Altera_Forum
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21 years ago

DDR vs. SDR RAM...

Anyone know if DDR Ram will fare better with the NiosII data master than SDRAM? After Dirk figured out it takes a whopping 12 clocks @50MHz (~240ns) per SDRAM read when not using the dma, we re...
Altera_Forum's avatar
Altera_Forum
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21 years ago

Hi Ken,

you are right, if you are using the /f-core, also internal RAM-accesses that miss the cache are slow. Like Jesse pointed out, using the /s-core would remove some clocks of delay as there is no cache, therefore there is no need for a check. Still you cannot achieve 1 or 2 cycles, even with internal RAM.

Using custom instructions would be the quickest, but also a more complicated, way. To achieve 1 cycle accesses will be tricky, but possible for streaming data. For random accesses you need a second cycle, because the internal SRAM is always registered (at least at Cyclone).

If you would like me to design it for you, I would be happy to get a mail.

Regards,

Thomas