Reply To: Usage of random functions (e.g RandSlv)
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thanks for that recommendation.
Meanwhile I found another working solution too.
For using the RandomPType QuestaSim insists that the function has to be impure. I remembered from your documentations that there’s some link between protected types, shared variables and impure functions.
So I came up with this solution:
shared variable RandomData : RandomPType;
impure function DataGenerator(DataWidth : natural) return std_logic_vector is
-- check seed for initial value (from RandomBasePkg Random Seed declaration)
if RandomData.GetSeed = RandomSeedType(integer_vector'(1,7)) then
report "Info: Seed generated for DataGenerator:RandomData";
return RandomData.RandSlv(0, 2**Datawidth-1, DataWidth);
And calling the Function like this works just fine:
for i in 0 to 99 loop
wait until falling_edge(clock); -- just creating some delay
DataIn <= DataGenerator(DataIn'length);
wait until rising_edge(clock);
I think it would work with a procedure as well. (hopefully)
The good thing is that I do not have to double declare the RandomPType outside and inside the function and do not have to transfer the actual values. Instead I just have a constant in the function argument list.
Thanks for reminding me about the Random Package UG.
I saw it was there, but just read the OSVVM UG and the Protected types paper. Somehow I couldn’t resist to try it out immediately. 🙂