Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
9 years ago

ROM inferring problem

Hello;

In my design I write a VHDL code to infer ROMs. It were specified to be M9k with the following attribute:

attribute romstyle : string;

attribute romstyle of q: signal is "m9k";

Then after compiling I didnot find these settings in the fitter report, however, I find other attributes for the other entities. Also the ROMs are inferred with the Altsync_ram function but didnot consume any M9K blocks. each ROM size is 8*256 I use the stratix3-EP3SL150F1152 chip. My question is what attributes can force the synthesis to use M9K bloks to infefer these ROMs?

Thanks

2 Replies

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

    If you are using the altsync_ram IP block, then you are not inferring a rom. Inference is done by writing behavioural RTL that behaves like a ram and the synthesis will replace your code with an altsyncram. If you are using an altsynram you need to set the ram style paramters.

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

    There are examples of inferred memory in volume 1 chapter 12 of the Quartus handbook.