Creating HDL Text Modules, страница 34

cc merge                         -merge_hierarchies -dir $DSN\coverage1          -dir $DSN\coverage2

                                        -dest $DSN\coverage_merged

7.12 Merge Code Coverage Data

You can also merge the Code Coverage Data on the ‘per-unit’ basis. Using this technique, information for the units will be combined regardless of their location in hierarchy.

cc merge                         -merge -dir $DSN\coverage1 -dir $DSN\coverage2

                                        -dest $DSN\coverage_merged

                                              Toggle Coverage

                                              Toggle Coverage is a tool integrated within Active-HDL.

Toggle Coverage measures design activity in terms of changes of signal logic values.

It efficiently helps to verify the quality of the stimulus and locate "dead" structures of the design. Signals that were not initialized during simulation or are not exercised properly by the testbench can be easily identified.

7.13  Enabling Toggle Coverage

To enable Toggle Coverage session you have to:

•  Initialize simulation session

•  Use toggle command to start Toggle coverage session. Signals that should be monitored have to be specified explicitly in the command line (use of wildcards is allowed).

asim bjack_tb

toggle -toggle_type full /UUT/I17/*

•  A report is written automatically to the ./toggle subfolder when the endsim command is used or when the Toggle Coverage engine is switched off with the toggle –off command.

7.14  Toggle Coverage modes

                                              The Toggle Coverage engine can generate four different types of reports:

•  Init mode

•  Assign mode

•  Full mode

•  Activity mode

The mode is specified with the –toggle_type switch.

7.15  Toggle Coverage - Init mode

The Init mode (-toggle_type init) checks if selected signals have been at least once set to ‘0’ or ‘1’ value. This mode is useful to verify whether selected signals were initialized or not.

Please open the toggle_example design and execute run_init_mode.do macro.  This macro invokes toggle coverage with proper switches listed below:

toggle -toggle_type init -rec /*

                             7.16  Toggle Coverage - Init mode

After execution of run_init_mode.do macro appropriate toggle coverage report file is generated and then displayed in HDL Editor window. You can check that some signals, e.g. D_L and D_H  have not been properly initialized:

                                                                                  RESULTS

Signal Name                   Toggled

BUST                                       YES

D_H [1:0]                       NO

D_L [3:0]                       NO

END_SIM                                YES

GEN_CLK                               YES

GEN_RES                               YES

HOLD                                      YES

                             7.17 Toggle Coverage - Assign mode

The Assign mode provides information on how many pulses happened on a signal while the signal was being monitored.

In Verilog designs, the Toggle Coverage counts 0 and 1 pulses. For VHDL the L and H values of the std_ulogic type are also included in the statistics.

To invoke gathering assign data for the NEW_CARD signal, please execute run_assign_mode.do macro:

toggle -toggle_type assign NEW_CARD

                       7.18 Toggle Coverage - Assign mode

After execution of run_assign_mode.do macro, a new toggle coverage report file is generated. 

This mode, for example, can be used to count

how many times action “new card” is executed:

                                                           RESULTS

Signal Name          Toggled     "0" assigns "1" assigns

NEW_CARD         YES           15                15

7.19 Toggle Coverage - Full mode

In the Full mode signals are checked to detect if both rising and falling edges occurred.

Additionally, the edge definition can be customized with the -posedge/-negedge switch.