ModelSim SE User's Manual - Electrical and Computer Engineering

Examples
Optional arguments can be omitted by using commas or by leaving them out if they are at
the end of the argument list. For example, to specify only the SDF file and the instance to
which it applies:
$sdf_annotate("myasic.sdf", testbench.u1);
To also specify maximum delay values:
SDF to Verilog construct matching
$sdf_annotate("myasic.sdf", testbench.u1, , , "maximum");
The annotator matches SDF constructs to corresponding Verilog constructs in the cells.
Usually, the cells contain path delays and timing checks within specify blocks. For each
SDF construct, the annotator locates the cell instance and updates each specify path delay
or timing check that matches. An SDF construct can have multiple matches, in which case
each matching specify statement is updated with the SDF timing value. SDF constructs are
matched to Verilog constructs as follows:
IOPATH is matched to specify path delays or primitives:
SDF Verilog
(IOPATH (posedge clk) q (3) (4)) (posedge clk => q) = 0;
(IOPATH a y (3) (4)) buf u1 (y, a);
The IOPATH construct usually annotates path delays. If ModelSim can’t locate a
corresponding specify path delay, it returns an error unless you use the
+sdf_iopath_to_prim_ok argument to vsim (CR-373). If you specify that argument and the
module contains no path delays, then all primitives that drive the specified output port are
annotated.
INTERCONNECT and PORT are matched to input ports:
SDF Verilog
(INTERCONNECT u1.y u2.a (5)) input a;
(PORT u2.a (5)) inout a;
Both of these constructs identify a module input or inout port and create an internal net that
is a delayed version of the port. This is called a Module Input Port Delay (MIPD). All
primitives, specify path delays, and specify timing checks connected to the original port are
reconnected to the new MIPD net.
PATHPULSE and GLOBALPATHPULSE are matched to specify path delays:
SDF Verilog
(PATHPULSE a y (5) (10)) (a => y) = 0;
(GLOBALPATHPULSE a y (30) (60)) (a => y) = 0;
Verilog SDF UM-445
ModelSim SE User’s Manual