How to design Asynchronous circuit (microcontroller (16 bit to 64))

Discussion in 'The Projects Forum' started by Brian, Feb 13, 2007.

  1. Brian

    Thread Starter New Member

    Feb 13, 2007
    im planning to have a thesis w/ a general topic regarding asynchronous design but they where looking for more specific design

    i choose asynchronous because some major problem in synchronous circuit may resolve by using asynchronous like power consumption, high speed etc...

    any one have an idea of asynchronous design?method and standard? and some problem arise in designing asynchronous which need to be solve..

    hoping for your help and response

    thanks so much
  2. Papabravo


    Feb 24, 2006
    My experience suggests that most designers have abandoned asyncronous design because there is a lack of reliable design methods and the benefits of such a design are difficult to quantify.

    Power consumption has largely been dealt with by going to lower and lower core voltages while raising the clock rate.

    My only experience with asyncronous design was to get smacked by the chief engineer for an asyncronous dual port memroy controller that did not work and could not be made to work. After weeks of fruitless effort on the asyncronous design we made a syncronous design that worked in 24 hours. Needless to say I never looked back.

    If I was you I'd look for a new topic or possibly a new advisor.
  3. n9352527

    AAC Fanatic!

    Oct 14, 2005
    Do you have any particular design/circuit in mind? Microcontroller is a bit vague, if you are referring to a complete microcontroller core in asynchronous circuit, then it is, although possible, not a trivial process.

    These are debatable, generally proponents like to say these are true, but I have never come across a clear case example that supports these arguments. The outcomes highly depend on the particular implementations, for example you can compare the power-delay products of the implementation of asynchronous ARM core in third generation of AMULET3 or 3i processor with the original ARM core.

    The main points, that are usually omitted, are asynchronous circuits are more difficult to design and usually require larger area than synchronous ones. I would say that definite advantages are the lower EMI peak signature, the fact that there is no need to gate inactive circuits, process independency (to some degree) and there is no need to design a complex clock distribution tree.

    Note that the only point above that is directly related to commercial advantage is the lower EMI peak signature. The others are technical or design process advantages that may or may not end up as commercial advantages. This is the challenge, how to exploit these technical advantages into tangible commercial advantages.

    There is no one given standard of design. You are free to do it your own way, as long as it works :D Not many have proven design flows for asynchronous circuits. The ones that I know of are Handshake Solutions (owned formerly by Philips, have commercial tools and flow, proven in Philips design of asynchronous 8051 core, has an asynchronous ARM core project) and Amulet project (academic design of asynchronous ARM core, University of Manchester, formerly UMIST). Amulet has a spin-off called Silistix, which provides tools and flow for asynchronous design. No idea if it has firm projects or customers yet.

    I suggest you read through some of the papers on asynchronous circuits, and then identify the specific points that you need more clarifications on and we can discuss them here. Have a look at, which lists many papers in this field.
  4. Brian

    Thread Starter New Member

    Feb 13, 2007
    Thanks so much Sir Papabravo and Sir n9352527 for the information you both shared here in my inquiries, actually its just get me interested for asynchronous for the advantage of this design over synchronous, well i guess it will take me alots of readings and research, and a lack of resources for verifying and testing...

    maybe i would change my topic since in just starting, could you Sir suggest some specific topic for a thesis in my microelectronic course, and asking your help to be one of my good adviser, this will help me a lot for my study...thanks