Cyclone 3 - device has 66 M9K blocks. I set up 16384x36 memory chunk. It is 589824 bits, with device having 608256 bits. However quartus says it is too much, and says device needs to have 72 blocks to fit memory I need. What's an issue? Thank you for tips.

The issue will be the way you are using the ram, and you're not using it in an efficient way, so some on board ram is wasted.

Waisted? I try to use it the best way - as a single contiguous chunk. At leat it is my current understanding. Any suggestion other than stating that I do _something_ wrong?

It should be possible to build that memory using 64 M9K blocks and some logic elements as well. This memory will be spread across the entire chip so do you really need such a large memory? Are you sure that memory is the only one in your design? If you include IP or large lookup tables they could also be consuming on-chip memory resources.

--- Quote Start --- It should be possible to build that memory using 64 M9K blocks and some logic elements as well. This memory will be spread across the entire chip so do you really need such a large memory? Are you sure that memory is the only one in your design? If you include IP or large lookup tables they could also be consuming on-chip memory resources. --- Quote End --- This is what I am curious about. I planned to have 64 blocks, but it wants 72. error (170048): selected device has 66 ram location(s) of type m9k. however, the current design needs more than 66 to successfully fit After splitting to two memories 16K words each * 18 bits, it still wants 72 blocks scope_mem:buffer0_ram|altsyncram:altsyncram_component|altsyncram_pho1:auto_generated|ALTSYNCRAM AUTO Simple Dual Port Dual Clocks 16384 18 16384 18 yes no yes no 294912 16384 18 16384 18 294912 36 None Unassigned 1 scope_mem:buffer1_ram|altsyncram:altsyncram_component|altsyncram_pho1:auto_generated|ALTSYNCRAM AUTO Simple Dual Port Dual Clocks 16384 18 16384 18 yes no yes no 294912 16384 18 16384 18 294912 36 None Unassigned 2 And yes, I need large buffer, spanning through whole internal memory. edit: just notices i use dual-port memory model. does it change anything while size of the memory remains the same?

It depends on the dual-port mode you are using - see pages 43-46. http://www.altera.com/literature/hb/cyc3/cyclone3_handbook.pdf Based on the error message, I'd guess you were trying to use true dual-port mode. Cheers, Dave

Why it wants mofr M9K blocks | Altera Community

13 Replies

Altera_Forum
Honored Contributor
13 years ago
It should be possible to build that memory using 64 M9K blocks and some logic elements as well. This memory will be spread across the entire chip so do you really need such a large memory?

Are you sure that memory is the only one in your design? If you include IP or large lookup tables they could also be consuming on-chip memory resources.
Altera_Forum
Honored Contributor
13 years ago
Waisted? I try to use it the best way - as a single contiguous chunk. At leat it is my current understanding.
Any suggestion other than stating that I do _something_ wrong?
Altera_Forum
Honored Contributor
13 years ago
The issue will be the way you are using the ram, and you're not using it in an efficient way, so some on board ram is wasted.

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Why it wants mofr M9K blocks

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