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Altera_Forum
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18 years ago

Missing virtual jtag documentation

Hello, I started to use the sld_virtual_jtag Megafunction for low level debugging puposes, using Tcl interface with quartus_stp. Now I'm considering possible operation with non-Altera JTAG inte...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
18 years ago

Hello,

you guessed right so far, Altera support stated:

--- Quote Start ---

Unfortunately there is no document to describe the detailed infrastructure operation codes for virtual JTAG Megacores.

--- Quote End ---

They suggest to use -show_equivalent_device_ir_dr_shift option to evaluate the command coding.

But I think, virtual jtag interface operation can be basically understood. Some information is shown in Quartus report files, e. g. the jtag hub's node_info data. This info is read during virtual jtag node enumeration by Quartus tools and shows the number of connected instances, each node type and virtual ir register length. The node index and select bit coding results implicitely from node_info data.

Best regards and Happy New Year!

Frank