Is there any document describing Altera Jtag components?

[Altera_Forum]

I find the component **_jtag in the library of Quartus, but cann't find detailed information about it. 

 The component is as below:   component cyclone_jtag  generic (  lpm_hint : string := "UNUSED";  lpm_type : string := "cyclone_jtag" );  port(  clkdruser : out std_logic;  ntrst : in std_logic := '0';  runidleuser : out std_logic;  shiftuser : out std_logic;  tck : in std_logic := '0';  tckutap : out std_logic;  tdi : in std_logic := '0';  tdiutap : out std_logic;  tdo : out std_logic;  tdouser : in std_logic := '0';  tdoutap : in std_logic := '0';  tms : in std_logic := '0';  tmsutap : out std_logic;  updateuser : out std_logic;  usr1user : out std_logic  ); end component;

[Altera_Forum]

The JTAG components are not well documented. 

 Here's my notes:  http://www.ovro.caltech.edu/~dwh/correlator/pdf/vjtag.pdf  You'll find that the cyclone_jtag is a device-specific implementation of some other generic JTAG component.  What were you trying to implement?  Cheers, Dave

[Altera_Forum]

Hi, Dave, 

 I am trying to use these family_jtags to connect our JTAG-supported soft modules(inside FPGAs), so we can access both vendor's JTAG component and our soft modules by software.  Your notes give the information about virtual jtag, but the component "family_jtag" is the primitive. What I really want to use is the primitive.  Is there any detailed information about this component's pinout?

[Altera_Forum]

--- Quote Start ---   I am trying to use these family_jtags to connect our JTAG-supported soft modules(inside FPGAs), so we can access both vendor's JTAG component and our soft modules by software.  Your notes give the information about virtual jtag, but the component "family_jtag" is the primitive. What I really want to use is the primitive.  Is there any detailed information about this component's pinout?  --- Quote End ---    The *only* supported JTAG component is the SLD_Virtual_JTAG component. Altera's JTAG-to-Avalon components are internally constructed from a component that is essentially identical to this part too, eg., see these notes:  http://www.ovro.caltech.edu/~dwh/correlator/pdf/altera_jtag_to_avalon_analysis.pdf  I'm still not quite clear on your requirements:  1) If you have a JTAG-like component that you want to access, you need to connect it via the SLD_Virtual_JTAG component.  2) If you have a component with registers, then you can access it via a JTAG-to-Avalon-MM bridge, just provide your component with an Avalon-MM slave interface.  Can you please clarify.  Cheers, Dave

[Altera_Forum]

My application is the first one. 

 Did you mean users can not use "cyclone_jtag" component in the "..\quartus\libraries\vhdl\cyclone_components.vhd"?  What's this "cyclone_jtag" component for?  Regards, Ryan

[Altera_Forum]

--- Quote Start ---  My application is the first one.   --- Quote End ---   Then Altera will only support you if you use the SLD_Virtual_JTAG component.     --- Quote Start ---   Did you mean users can not use "cyclone_jtag" component in the "..\quartus\libraries\vhdl\cyclone_components.vhd"?  What's this "cyclone_jtag" component for?   --- Quote End ---   It might be used when creating a simulation model.  You might also find that if you use a MegaWizard to instantiate a JTAG component that this component is internally used. However, direct instantiation of the SLD_Virtual_JTAG should give you identical (or at least very similar) control.  Keep in mind that any VHDL you can read in the atoms files or the low-level device files *is not real*, i.e., you will never get to see what Altera synthesis files look like. That is all part of their secret-sauce.  If you are trying to create a vendor-neutral interface to your JTAG components, then you need to go through the SLD_Vitual_JTAG components for Altera, and the BSCAN components for Xilinx, and I forget what the JTAG components are called for Lattice. Bottom line is you have to use a vendor specific component to access your vendor neutral code.  Cheers, Dave

[Altera_Forum]

I see. 

 Thanks for your advice.  Regards,  Ryan

[Altera_Forum]

--- Quote Start ---   Thanks for your advice.   --- Quote End ---   No problem. Hopefully it saved you some time.  If you have a specific use-case that you do not want to discuss here, eg., a code example, just send me an email directly (to my forum name).  Cheers, Dave