How Can I Hold Off an Assertion Until Sync is Established Using a Local Variable?

You needed the property “or” operator.

property data_parity_prop (clk, rst, d, available, parity);
  bit flag = 0;
  @(posedge clk) disable iff (rst !== 1)
((d == SYNC_DATA), flag = 1) or flag |-> ^d ^ available ^ parity;
endproperty
// Could also use
property data_parity_prop (clk, rst, d, available, parity);
  bit flag = 0;
  @(posedge clk) disable iff (rst !== 1)
  ($rose(d == SYNC_DATA), flag = 1) or flag |-> ^d ^ available ^ parity;
endproperty
// Suggest you also use the default disable iff

property_expr ::=
sequence_expr
| strong ( sequence_expr )
| weak ( sequence_expr )
| ( property_expr )
| not property_expr
| property_expr or property_expr // <-----------
| property_expr and property_expr
| sequence_expr |-> property_expr
| sequence_expr |=> property_expr


Ben Cohen
http://www.systemverilog.us/ ben@systemverilog.us

  • A Pragmatic Approach to VMM Adoption 2006 ISBN 0-9705394-9-5
  • SystemVerilog Assertions Handbook, 2005 ISBN 0-9705394-7-9
  • 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 0-9705394-2-8
  • 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