The following would be easier. Add the timeunit, timeprecision.
module timem;
timeunit 1ns; timeprecision 100ps;
bit clk, a, b;
initial forever #5 clk=!clk;
property period_chk;
time current_time;
('1,current_time = $time ) ##1
($time -current_time == 10ns);
endproperty
ap_time: assert property(@(posedge clk) period_chk);
endmodule
Ben Cohen
http://www.systemverilog.us/ ben@systemverilog.us
- SystemVerilog Assertions Handbook 3rd Edition, 2013 ISBN 878-0-9705394-3-6
- 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 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