VHDL to CMOS

Discussion in 'VHDL' started by o pere o, Jun 28, 2013.

  1. o pere o

    o pere o Guest

    In the last months we have been designing an RF CMOS chip. The next step
    will be to integrate some functionality that now is run in an FPGA into
    the same chip.

    I guess there has to be a more or less straightforward way to translate
    a VHDL description into a layout, but don't know which software package
    we should be looking at. How straightforward is this? How good is the
    final result? Which tools are required? Is some manual place&route of
    the final logic cells (which are black boxes in our technology) still
    required?

    Thanks for any input!

    Pere
     
    o pere o, Jun 28, 2013
    #1
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  2. o pere o

    rickman Guest

    Chip design is not my forte, but my understanding is that digital logic
    and RF put different requirements on the process and are not often
    combined on a single chip. There is typically a compelling need when
    this is done, like sales of millions of chips.

    Are you designing a chip with a vendor in mind? They typically can
    point you to tools and provide you with libraries.
     
    rickman, Jun 29, 2013
    #2
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  3. o pere o

    react66 Guest

    Don't get taken for a ride buying tools. Best bet is to see if you can pay the chip vendor to layout a block for you. If you are using a larger technology for 3.3v CMOS, like .35 u, it is not too hard to synthesize a block using some legacy tool like LEONARDO, then get the vendor to do clock insertion, layout and extraction plus a static timing run, find/fix antenna problems and give you back the block for the top level layout.

    You don't want to buy all the tools just to do this. The vendor might charge you $5K if you give him the Verilog netlist and some idea of the block shape.

    Synthesis and simulation should be done before this handoff, and clock gating should be done if you care about power (who doesn't). It is best to keepthe synthesis under your control. Only if you are using a deep submicron process you should probably get the vendor to do this part too.

    Check http://opencircuitdesign.com, I think Tim has an open synthesis tool but it might need Verilog input.
     
    react66, Jul 1, 2013
    #3
  4. o pere o

    o pere o Guest

    We are targeting UMCs mixed-mode 180nm process. This should be a process
    able to put RF and digital stuff on the same chip. And yes, we get some
    libraries for digital parts, just black boxes that you may layout as you
    like. If you do this by hand, from RTL description for instance, this
    can be cumbersome if you have more than a few dozens of boxes...

    Pere
     
    o pere o, Jul 1, 2013
    #4
  5. o pere o

    o pere o Guest

    As this is for a non-profit research project, we may have the chip done
    and get access to some of the tools at a (hopefully) reasonable cost. I
    will have a look at the synthesis tool you mentioned -I wasn't aware of
    it. Thanks!

    Pere
     
    o pere o, Jul 1, 2013
    #5
  6. Are you in academia? There may be a way to get cheap access to the tools
    through a national academic programme, for example Europractice in Europe:
    http://www.europractice.stfc.ac.uk/welcome.html

    But be aware that it may take a long time to become familiar with the tools
    - if you're only going to do this once, probably worth contracting it out.

    Theo
     
    Theo Markettos, Jul 5, 2013
    #6
  7. o pere o

    o pere o Guest

    Yes, we are already members of Europractice. This was the only way to go
    in our previous design. And the tools we have been using were certainly
    a PITA. Now that the pain is slowly receding, I was wondering which tool
    would help us going on with the digital part :)

    Pere
     
    o pere o, Jul 8, 2013
    #7
  8. FWIW I've used Synopsys tools, where Design Compiler is the bit that
    synthesises verilog (and presumably VHDL too) into standard cells.

    Theo
     
    Theo Markettos, Jul 10, 2013
    #8
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