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Altera_Forum
Honored Contributor
Honored ContributorLE and memory blocks in a cyclone
Hello,
I'm quite new in the world of the FPGA, indeed, I'm an engineer student in end-of-studies internship which is about using a FPGA. Well, I'm telling you that because I guess that you will think my question is a question of newbies :oops:. When I start studying FPGA, my teachers said that the most important characteristic of these devices is the number of Logic Elements. But during my internship, I did some architectures using IP and then, after a full compilation, I realized that the characteristic which constrained me the most is the "total memories bits". After few research, I understood this characteristic was the representation of the memories blocks (like M9K). Here come my question, what is the constitution of a memory block? is-it a very important parameter in a fpga? Example: My FPGA have 600K memories bits and 22K LE. After Quartus compilation, I realize that my architecture need 500K memories bits but only 2K LE. can i use le instead of memories block for 1 or 2 ip? I hope that I explained my problem clearly, Thank in advance, Clément.14 Replies
Altera_ForumLEs can be used as memory, but they are far less dense than ram. So you can quickly lose all your LEs to larger rams that have timing issues. LE rams are meant for small high speed applications.
- Altera_Forum
But so, what do I do to store my functions with the LEs and not with the memories blocks? and vice versa?
- Altera_Forum
See the "ramstyle" attribute
http://quartushelp.altera.com/14.0/mergedprojects/hdl/vhdl/vhdl_file_dir_ram.htm - Altera_Forum--- Quote Start --- See the "ramstyle" attribute http://quartushelp.altera.com/14.0/mergedprojects/hdl/vhdl/vhdl_file_dir_ram.htm --- Quote End --- Thanks a lot !! That's exactly what I need.
