Creating HDL Text Modules, страница 57

•  Open the previously saved CNT_BCD.AWF waveform file. Use the Resources tab of the Design Browser. Double click on the CNT_BCD.awf item to open the waveform

•  Make sure the top-level entity-architecture pair is set to cnt_bcd(cnt_bcd)

                                                  4.3 Setting Code Breakpoints

•  Open the CNT_4b.vhd file

•  Place the breakpoint in the CNT_4b.vhd file (press the F9 key) on the following line:

                                                  Qint <= Qint + 1;

•  Initialize simulation (Simulation | Initialize Simulation menu option).

•  Open the Watch window (View | Watch menu option).

                                                4.4 Setting up the Watch window

•  Click the U1:cnt_4b(cnt_4b) item in the Design Browser / Structure tab.
Note: if you see different instance labels, click the first instance of CNT_4b

•  Using ‘drag & drop’ feature, add the FULL and Qint signals to the Watch window

                        4.5 Watch Display Radix

•  To change the display radix in Watch window, select any signal and invoke the pop-up menu (right click on signal). Choose Display Options and choose (e.g. Binary for Vectors) in the Preferences window

                                              4.7 Setting Signal Breakpoints

•  In Simulation menu choose Edit Breakpoints option and switch to Signal Breakpoints tab

•  Use Add signals button to invoke dialog which lets you pick the signals you want to use to stop simulation 

•  Select FULL output of U1 instance of cnt_4b and click on the Add button

                                                 4.8 Setting Signal Breakpoints

•  Use the Edit condition button to modify breakpoint’s properties

•  Select Value radio and enter ‘1’ in the edit box next to it

•  Hit OK to confirm your selections

                                                  4.9 Running Debug Simulation

•  Perform the Run operation (Simulation | Run menu option) several times & observe the signal values in the Watch window. Notice the messages in console window.

   NOTE: It is possible to change the value of the variable during simulation by editing it in the Watch window (in this simulation there are no variables to change).

•  Exclamation marks on left hand side of the signal name in Watch window mean that an event took place in current simulation cycle

•                Probes in Block Diagram Show actual values of the signals. The display radix can be customized in the Diagram | Probes Appearance

                                                   4.10 Trace

•  When the simulation stops at Code Breakpoint set in CNT_4b.vhd, press Trace button            to step through execution of your code

•  Please note pop-up hints showing actual values and types of objects near the mouse cursor 

                                    4.11 Enabling Show Event Source feature

•  Finish the simulation (Simulation | End Simulation)

•  Remove all Breakpoints (Simulation | Clear All Breakpoints)

•  Finish the simulation (Simulation | End Simulation)

•  Remove all Breakpoints (Simulation | Clear All Breakpoints)

                                     4.12 Using Show Event Source feature

•  Switch to Waveform Editor window (CNT_BCD.AWF) and run simulation until 14450 ns

•  Right click on the event on BCD_A signal at current simulation time and use Show Event Source Option

•  Switch to Waveform Editor window (CNT_BCD.AWF) and run simulation until 14450 ns

•  Right click on the event on BCD_A signal at current simulation time and use Show Event Source Option

                                  4.13 Using Follow Object

•  You should end up in line 61 of CNT_4b.vhd, where the Q output of counter is assigned Qint value