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M-RAM allocation in Stratix EPS125B672C6

Hi ,

I am using Altera Quartus II version 4.0 . The EPS125 device has 138 M4K blocks

224 M512 blocks 2 number of 512K Mram blocks

has a total of 1,944,576 bits.

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the problem i am facing is i am trying to fit in 4 buffer data blocks each of size 16384*14 bits (total 229376*4 =917504) plus i have additional fifo and single port Ram of sizes 8192 , and

1500 bits

The problem is though there is adequate RAM available , I am not able to fit in all the memory; only 48% of the RAM is used.

The fitter resourse summary says more M-Ram blocks are required but most of M4K and M512 blokcs are not used. ie 40/224 M512 blocks are used, 2/138 M4K blocks and 2-MRam blocks...

I am fairly new to FPGAs and stuff so i would appreciate all help.

thanks and regards.

Reply to
nandits11
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See if

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fits your needs, it allows you to have multiple fifo's in one MRAM

Moti

Reply to
motiw

Hi,

It does appear you have enough RAM in the device. You should put 2 of your buffer data blocks in M-RAMs (one M-RAM for each), and two more in M4K RAMs (56 M4Ks for each). The remaining RAMs look to be small and appear to be fitting fine.

You have two options to make this happen.

  1. In the altsyncram megafunction, choose the type of the memory block to be M4K for two of the buffers. The other two should use a different altsyncram instantitation that either leaves RAM type set to Auto, or chooses M-RAM.

  1. Upgrade to a more recent version of Quartus II. I believe that the latest versions of Quartus II will automatically figure out that you don't have enough M-RAMs to implement all four of these data buffers, and will move two of them to use M4Ks, when you leave the RAM type set to Auto (the default).

Hope this helps.

Vaughn Betz Altera

Reply to
vbetz

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