Advanced Digital Design (WS 2019)

The course focuses on advanced timing issues in digital design. The need for design methodologies is elaborated, and alternatives to the traditional synchronous design style are discussed, such as "globally asynchronous locally synchronous (GALS)" and purely asynchronous styles (bounded delay as well as delay insensitive). The scope spans from the underlying theory to practical design flow. In context with synchronous design and GALS, metastability issues are treated in much detail.

General Information about the Course

The course comprises a mix of lecture blocks, exercise blocks and labs. The latter two are concerned with discussing homeworks (results of questions/calculations and circuit designs, respectively). The labs are optional as an extra course (LU) that can be taken in conjunction with the lecture/exercise (VU). The lecture exercise can be attended without taking the lab, but not vice versa.

The course materials (lecture slides, homework assignments, auxiliary material) can be downloaded in TUWEL. The solutions must be provided as .pdf and uploaded to TUWEL on the day before the respective exercise block, before 12:00 noon.


Course Dates

Please register for the course in TISS

Introduction and Overview of Courses :

  • An overview of the Courses offered by our Group in the winter term 19/20 will be given in an introductory lecture on Tuesday, Oct 1   at 9:15 in the Seminar room TI .

Regular Lectures and Exercises:

  • The regular lecture date is Wednesday  10:00 c.t. to 12:00 in seminar room BA 02A.
  • In addition there are extra slots for the presentation of the homeworks and (optional) lab exercises, namely on selected Tuesdays 13:00 c.t. to 15:00 in seminar room TI
  • for detailed schedule see table below


Final Exam:

  • The final written exam will be held on Jan 29, 2020, 10:00 to 12:00 in seminar room BA 02A.


Course Materials

The lecture slides, assignments as well as supplementary material are available in TUWEL.

For the lectures on Asynchronous Logic Design the following text book is additionally recommended:

Jens Sparso and Steve Furber
Principles of Asynchronous Design -- A Systems Perspective
Kluwer Academic Publishers, 2001

For students a free .pdf version of chapters 1 - 7 of this book is available at Jens Sparso's homepage.

A very good survey on asynchronous logic can also be found in the following articles:
S.M. Nowick, M. Singh, Asynchronous Design—Part 1: Overview and Recent Advances, IEEE Design & Test, vol 32(3) and
S.M. Nowick, M. Singh, Asynchronous Design—Part 2: Systems and Methodologies , IEEE Design & Test, vol 32(3).

A very good introduction and survey of static pipelines can be found in our students' project report on CLAP. Further details about Asynchronous Pipelines are given in the survey article S.M. Nowick, M. Singh, High-Performance Asynchronous Pipelines: An Overview, IEEE Design & Test of Computers, vol 28(5), 2011

A comparison of delay-insensitive codes as well as an efficient method for building completion detectors can be found in conference papers that resulted from one of our students' projects.

For additional reading about Synchronizers the following book

David J. Kinniment and Alex Yakovlev
Synchronization and Arbitration in Digital Systems

as well as the article Ran Ginosar, Metastabilty and Synchronizers: A Tutorial, IEEE Design & Test of Computers, vol 28(5) , 2011

are recommended. A comprehensive survey on synchronizer techniques is given in the Master thesis by Robert Kutschera.



Month Date Day Time Topic
October 2 Wed 10:00 - 12:00 1 - Organization, The Role of Time
9 Wed 10:00 - 12:00 2 - Timing Model & Synchronous Design
16 Wed 10:00 - 12:00 2 - Timing Model & Synchronous Design
November 5 Tue 13:00 - 15:00 3 - Metastability Models
6 Wed 10:00 - 12:00 3 - Metastability, Synchronizers
12 Tue 13:00 - 15:00 4 - Metastability Measurement, GALS Design
13 Wed 10:00 - 12:00

4 - GALS Design, Pausable Clocks

19 Tue 13:00 - 15:00 5 - Asynchronous Design - Principles, Bundled Data
20 Wed 10:00 - 12:00 RA - Discussion Exercise 1
26 Tue 13:00 - 15:00 DA - Discussion Design 1
27 Wed 10:00 - 12:00 6 - Delay Insensitive Asynchronous Design Styles
December 4 Wed 10:00 - 12:00

6 - Delay Insensitive Asynchronous Design Styles

10 Tue 13:00 - 15:00

7 - Asynchronous Data-flow Structures

11 Wed 10:00 - 12:00

RB - Discussion Exercise 2

17 Tue 13:00 - 15:00 DB - Discussion Design 2
18 Wed 10:00 - 12:00 8 - Synthesis of Control Circuits
January 8 Wed 10:00 - 12:00 9 - Description Methods for asynchronous design
14 Tue 13:00 - 15:00 10 - Asynchronous EDA
15 Wed 10:00 - 12:00 RC - Discussion Exercise 3
21 Tue 13:00 - 15:00 DC - Discussion Design 3
22 Wed 10:00 - 12:00 11 - 50 Shades of Synchrony
29 Wed 10:00 - 12:00 Written Exam



The grading for the lecture will be based on the following scheme

  • exercises (quality of submitted solutions, presentation of solution): 40%
  • written exam: 40%
  • the remaining 20% can be attained through contributions to discussions during lectures and exercise discussions

For a positive grade, at least 40% of the achievable credits in exam and exercises must be reached, as well as at least 50% overall; the borderlines for the other grades will be at 62.5%, 75%, 87,5%, accordingly.


For the lab the grading will be as follows:

  • quality of submitted solutions: 75%
  • presentation of solutions: 25%

Again at least 50% overall must be attained for a positive grade; the borderlines for the other grades will be at 62.5%, 75%, 87,5%, accordingly.



the following competences shall be conveyed:

  • deal with challenging (timing) issues in digital design (esp. clock domain crossing)
  • understand the theoretical underpinningsof the synchronous design style and its alternatives
  • choose the appropriate style for a given problem
  • understand the involved limitations


  • basic concept and limitations of synchronous design
  • metastability: causes and effects, modelling, MTBU estimation and measurement
  • design and implementation of synchronizers for different settings
  • GALS-Systems (timing domain crossing, pausable clocking)
  • internal design, function and limitations of the basic building blocks of asynchronous design: Muller C-Element and Mutual Exclusion Element
  • asynchronous design methods (bundled data, delay insensitive), handshake principles (2-phase/4-phase) and timing models (bundled data, delay insensitive,...)
  • fundamental description methods for asynchronous design
  • comparison of synchronous and asynchronous logic


Dipl.-Ing. Dr.techn. Steininger Andreas