Forbidden switching patterns to mitigate crosstalk on parallel data buses — CODEC design

Instead of applying physical techniques to prevent crosstalk on off-chip parallel data buses, another approach is to code the sent information, [1]. Through developing of a crosstalk avoidance code (CAC) is possible to create a forbidden transition channel (FTC) that prevents transitions responsible for generating crosstalk, [2]. Rules used in developing a CAC can be very complex, and because of that in some papers is explained only the coding algorithm without given a description of the coder/decoder (CODEC). Some of the CAC presented in literature can have only a theoretical point of view, the physical implementation raising problems regarding the real time execution requirements of such a system [3]. In section IV of the paper is explained how the proposed CAC in [4] can be extended to code a larger bus structure and implement the CODEC. In order to compare the proposed CAC performances, were implemented other two algorithms that try to mitigate crosstalk effects ([1] and [2]). In the paper are presented not only SPICE results, but also measured results obtained on a physical off-chip parallel data bus test setup.