Honored Contributor
Honored ContributorI think that insisting in using VJI for simulation purposes only, when VJI won't be used at all in real hardware, doesn't make much sense.
One of the main problems of simulating JTAG, is that the Altera model doesn't bring the JTAG signals to the top level. Actually, the JTAG interface is modelled as a black box silicon without any connection to the outside world. That would be tricky to simulate. I would instantiate a custom SOPC component, which could be even your own version (for simulation purposed only) of VJI. Or even your own version of JTAG UART, if you prefer. Forget about any actual JTAG protocol, there is no need for it. Then use simulator specific tools to access registers in that custom SOPC component. For instance, ModelSim would let you access buried signals from your testbench.
