Title
On the Appropriate Handling of Metastable Voltages in FPGAs.
Abstract
The significant process, voltage and temperature (PVT) variations seen with modern technologies make strictly synchronous design inefficient. Asynchronous design with its flexible timing is a promising alternative, but prototyping is difficult on the available FPGA platforms which are clock centric and do not provide the required functional primitives like mutual exclusion or Muller C-elements. The solutions proposed in the literature so far work nicely in principle but cannot safely handle metastability issues that are inevitable even at some interfaces in asynchronous designs. In this paper, we propose reliable implementations of the fundamental function blocks required to safely convert potential intermediate voltage levels that result from metastability into late transitions that can be reliably handled in the asynchronous domain. These are high- and low-threshold buffers as well as a Schmitt-trigger. We give elaborate background analysis for the proposed circuits and also present the associated routing constraints to make the Schmitt-trigger circuit work properly in spite of the uncertain routing within FPGAs. Furthermore, we propose a procedure for an "in situ reliability assessment" of the specific Schmitt-trigger element under consideration, which also applies to metastability containment with high- or low-threshold buffers only. Our proof of concept is based on experimental results for both Xilinx and Altera FPGA platforms.
Year
DOI
Venue
2016
10.1142/S021812661640020X
JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS
Keywords
Field
DocType
Asynchronous,FPGA,metastability,Schmitt-trigger,low-threshold,high-threshold,measurement
Asynchronous communication,Schmitt trigger,Computer science,Voltage,Field-programmable gate array,Implementation,Electronic engineering,Metastability,Electronic circuit,Mutual exclusion,Embedded system
Journal
Volume
Issue
ISSN
25
3
0218-1266
Citations 
PageRank 
References 
1
0.37
7
Authors
4
Name
Order
Citations
PageRank
Thomas Polzer1498.43
Robert Najvirt2174.72
Florian Beck312.40
Andreas Steininger430849.17