Hello to all,
I'm new at working on CPLD in VHDL. Fortunately, I knew this language from University and I can understand and write it quite well.
Maybe, the greatest difficulties are the settings of the softwares.
I use Quartus II 9.1 SP2 and Altera-Modelsim 6.5b.
I made a project about a PWM. I also made a testbench for the Functional Simulation and it works quite well. Now, I would like to learn to do the Timing Simulation, but I can't understand how to do it.
I know that I need two files: the netlist (.vho) and the .sdo file.
In some way, I could obtain these files (in EDA Tool Settings, under Timing Analysis, I choose "Custom" with Format to Output Netlist "VHDL").
Now I have to use them in Modelsim. I could understand that:
1) In the library work of the project, I have to compile the vho file;
2) In the Simulation menu, I choose "Start simulation", on the tab "SDF" I open my .sdo file
3) In the "Start simulation" window again, on the tab design, I choose my top entity (not the testbench)
The simulation is ready to start, but there isn't any clock or stimulus to simulate...this is easy to understand, because in the functional simulation, that information were in the testbench...
But if I choose the testbench instead of the top entity in point 3), the vsim tells me errors about "No default binding for components"...
My questions:
A) am I doing anything wrong or this way is right?
B) have I got to set my stimuli in the .vho file? and in this case how?
C) what about .sdf max, min, latest? I understand that they are like constraints, so my simulation can tell me if they are not met, is it right? and how to set them?
D) it is important to set "Apply to Region" field in my point 2)? what is to be set there? the top level entity? in which format?
E) philosophically, is it important to do timing simulation if timing requirements are already met in classic time analyzer on Quartus II? (I set a Fmax of 100 Mhz)
F) this is a little off topic: why if I use Time Quest instead of Classic Time Analyzer, the requirement about the Fmax isn't met? (it tells me a Fmax of about 94 Mhz)
Thank you for the patience and the disponibility
ps: the device I use is from Max II family, if this can be useful.
I'm new at working on CPLD in VHDL. Fortunately, I knew this language from University and I can understand and write it quite well.
Maybe, the greatest difficulties are the settings of the softwares.
I use Quartus II 9.1 SP2 and Altera-Modelsim 6.5b.
I made a project about a PWM. I also made a testbench for the Functional Simulation and it works quite well. Now, I would like to learn to do the Timing Simulation, but I can't understand how to do it.
I know that I need two files: the netlist (.vho) and the .sdo file.
In some way, I could obtain these files (in EDA Tool Settings, under Timing Analysis, I choose "Custom" with Format to Output Netlist "VHDL").
Now I have to use them in Modelsim. I could understand that:
1) In the library work of the project, I have to compile the vho file;
2) In the Simulation menu, I choose "Start simulation", on the tab "SDF" I open my .sdo file
3) In the "Start simulation" window again, on the tab design, I choose my top entity (not the testbench)
The simulation is ready to start, but there isn't any clock or stimulus to simulate...this is easy to understand, because in the functional simulation, that information were in the testbench...
But if I choose the testbench instead of the top entity in point 3), the vsim tells me errors about "No default binding for components"...
My questions:
A) am I doing anything wrong or this way is right?
B) have I got to set my stimuli in the .vho file? and in this case how?
C) what about .sdf max, min, latest? I understand that they are like constraints, so my simulation can tell me if they are not met, is it right? and how to set them?
D) it is important to set "Apply to Region" field in my point 2)? what is to be set there? the top level entity? in which format?
E) philosophically, is it important to do timing simulation if timing requirements are already met in classic time analyzer on Quartus II? (I set a Fmax of 100 Mhz)
F) this is a little off topic: why if I use Time Quest instead of Classic Time Analyzer, the requirement about the Fmax isn't met? (it tells me a Fmax of about 94 Mhz)
Thank you for the patience and the disponibility
ps: the device I use is from Max II family, if this can be useful.