Issue about instruction register length

[Altera_Forum]

I can find below words, 

 "The instruction register length is determined automatically by the Quartus II JTAG server."  But, i really want to know what's the exactly value or range. For i worry about that my instructions' number of visual jtag would beyond its range.  There are many visual jtag instrucions when i design VJ interface to debug my project, so this is a serious issue for me.

[Altera_Forum]

The IP core is called virtual jtag, not visual JTAG. 

 The calculation of the Virtual Instruction encoding and length is documented in more detail than the Altera documentation in here:  http://www.ovro.caltech.edu/~dwh/correlator/pdf/vjtag.pdf  Cheers, Dave

[Altera_Forum]

Hi Dave: 

 Thanks!