Honored Contributor
Honored ContributorHi,
--- Quote Start --- 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. --- Quote End --- Seems you find out how this "enumeration" is performed. Would you mind share your finding? I have the same problem. The "-show_equivalent_device_ir_dr_shift" tells you how to implement the "virtual" shifting. But it doesn't tell you how to enumerate the virtual instances and get the info for assembling the virtual IR value and length. Guess not too difficult to "reserve engineer" sniffing the JTAG transactions. But you would save me a lot of time if you already did that. --- Quote Start --- which Altera apparently didn't wanted to disclose up to now. I don't see, that this information, effectively present at users fingertips, should be classified confidential. --- Quote End --- And not disclosing USB Blaster protocol seems even worse. Fortunately somebody reverse engineered the USB Blaster already.
