ModelSim SE User's Manual - Electrical and Computer Engineering

UM-442 18 - Standard Delay Format (SDF) Timing Annotation
VHDL VITAL SDF
ModelSim SE User’s Manual
VHDL SDF annotation works on VITAL cells only. The IEEE 1076.4 VITAL ASIC
Modeling Specification describes how cells must be written to support SDF annotation.
Once again, the designer does not need to know the details of this specification because the
library provider has already written the VITAL cells and tools that create compatible SDF
files. However, the following summary may help you understand simulator error messages.
For additional VITAL specification information, see "VITAL specification and source
code" (UM-93).
SDF to VHDL generic matching
An SDF file contains delay and timing constraint data for cell instances in the design. The
annotator must locate the cell instances and the placeholders (VHDL generics) for the
timing data. Each type of SDF timing construct is mapped to the name of a generic as
specified by the VITAL modeling specification. The annotator locates the generic and
updates it with the timing value from the SDF file. It is an error if the annotator fails to find
the cell instance or the named generic. The following are examples of SDF constructs and
their associated generic names:
SDF construct Matching VHDL generic name
(IOPATH a y (3)) tpd_a_y
(IOPATH (posedge clk) q (1) (2)) tpd_clk_q_posedge
(INTERCONNECT u1/y u2/a (5)) tipd_a
(SETUP d (posedge clk) (5)) tsetup_d_clk_noedge_posedge
(HOLD (negedge d) (posedge clk) (5)) thold_d_clk_negedge_posedge
(SETUPHOLD d clk (5) (5)) tsetup_d_clk & thold_d_clk
(WIDTH (COND (reset==1’b0) clk) (5)) tpw_clk_reset_eq_0