In reply to silverace99work:
- It is non-traditional to have drivers apply assignments as
#170ns arbif.cb.request <= 2; // BAD STYLE.
@arbif.cb arbif.cb.request <= 2; // GOOD STYLE
- I experimented with the following
https://www.edaplayground.com/x/3K4P
@ (cb1) a <= 2;
//@ (cb1) a <= 1; // NONBLOCKING assignment
#100 a <=1;
vs
@ (cb1) a <= 2;
@ (cb1) a <= 1; // NONBLOCKING assignment
// #100 a <=1;
below are the results
- Am not totatlly clear as to why #100 a <=1; is different than @ (cb1) a <= 1; when the 2 time occurrences are at the same identical time (e.g., 250ns).
After more thoughts, it looks like the #100 a <=1; behaves in a blocking type of fashion and the transaction completes. However, for the @ (cb1) a <= 1; the “a” get assigned in the NBA region. This results in different values being assigned to “b”. See from my book the various regions.
Ben Cohen
http://www.systemverilog.us/ ben@systemverilog.us
- SVA Handbook 4th Edition, 2016 ISBN 978-1518681448
- A Pragmatic Approach to VMM Adoption 2006 ISBN 0-9705394-9-5
- Using PSL/SUGAR for Formal and Dynamic Verification 2nd Edition, 2004, ISBN 0-9705394-6-0
- Real Chip Design and Verification Using Verilog and VHDL, 2002 isbn 978-1539769712
- Component Design by Example ", 2001 ISBN 0-9705394-0-1
- VHDL Coding Styles and Methodologies, 2nd Edition, 1999 ISBN 0-7923-8474-1
- VHDL Answers to Frequently Asked Questions, 2nd Edition ISBN 0-7923-8115