Altera Virtual JTAG IP Core - Manual (Page 27)

• In a real system, each instance of the Virtual JTAG megafunction works independently. In simulation,
multiple instances can work at the same time. For example, if you define a scan shift for Virtual JTAG
instance number 1 to happen at 3 ms and a scan shift for Virtual JTAG instance number 2 to happen at
the same time, the simulation works correctly.
If you are using the ModelSim-Altera simulator, the altera_mf.v and altera_mf.vhd libraries are provided
in precompiled form with the simulator.
The inputs and outputs of the Virtual JTAG megafunction during a typical IR scan shift operation are shown
in the figure below.
Figure 12: IR Shift Waveform
The figure below shows the inputs and outputs of the Virtual JTAG megafunction during a typical DR scan
shift operation.
Figure 13: DR Shift Waveform
Altera Corporation Virtual JTAG Megafunction (sld_virtual_jtag)
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27 Simulation Support
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2014.03.19