Re: PC to JTAG

You can definitely send JTAG commands using ChipScope 9.1, look at the 
TCL interface in the ChipScope 9.1 user guide, chapter 5:

http://www.xilinx.com/ise/verification/chipscope_pro_sw_cores_9_1i_ug029.pdf

There is also an example tcl script in the ChipScope installation which 
should provide you with the basics on how to use it correctly. 
ChipScope also provides a tcl interpreter using the script 
cs_xtclsh.bat/sh but ActiveTcl can also be used (meaning you can also 
use wish and create a simple GUI interface).

Try it out yourself from the command line:

'cd <chipscope install>/bin/<platform>'

run 'cs_xtclsh csejtag_example1.tcl -usb'



Matthew Hicks wrote:
> Great. That sucks.  You'd think Xilinx would provide a way to send JTAG 
> commands via iMPACT or maybe even Chipscope.  Guess not.
> 
> 
> ---Matthew Hicks
> 
> 
>> Matthew Hicks schrieb:
>>
>>> I read all of the documents I could find about using the JTAG port as
>>> a communications
>>> interface to the FPGA and implemented my own JTAG controlled logic.
>>> The
>>> problem is, none of the documents that I read gave a decent solution
>>> as to
>>> how to get access to the JTAG chain on the PC side of things.  I am
>>> using
>>> the Virtex II-Pro XUP board which has a USB front end to the JTAG
>>> interface.
>>> Is there an existing software solution available that I can use to
>>> send
>>> data to the user JTAG registers?  If not, then is there a Xilinx API
>>> that
>>> I need to use to write a program to do it myself or do I need to use
>>> a standard
>>> USB library?  Finally, once I am able to send data to the board's USB
>>> interface,
>>> is there a protocol that I need to follow to work with the Cypress
>>> USB chip
>>> or can I just send raw JTAG commands as the data payload?
>>> ---Matthew Hicks
>>>
>> No.
>>
>> you can talk to almst any other interface but not to the xilinx
>> platform cable as xilinx does not make the protocol info available.
>>
>> so, in generic talking to JTAG from PC is piece of cake.
>> but if the interface is xilinx platform usb, you just cant do it,
>> unless you load 3rd party firmware into the cypress chip...
>> Antti
>>
> 
> 

Great. That sucks.  You'd think Xilinx would provide a way to send JTAG commands 
via iMPACT or maybe even Chipscope.  Guess not.


---Matthew Hicks


> Matthew Hicks schrieb:
> 
>> I read all of the documents I could find about using the JTAG port as
>> a communications
>> interface to the FPGA and implemented my own JTAG controlled logic.
>> The
>> problem is, none of the documents that I read gave a decent solution
>> as to
>> how to get access to the JTAG chain on the PC side of things.  I am
>> using
>> the Virtex II-Pro XUP board which has a USB front end to the JTAG
>> interface.
>> Is there an existing software solution available that I can use to
>> send
>> data to the user JTAG registers?  If not, then is there a Xilinx API
>> that
>> I need to use to write a program to do it myself or do I need to use
>> a standard
>> USB library?  Finally, once I am able to send data to the board's USB
>> interface,
>> is there a protocol that I need to follow to work with the Cypress
>> USB chip
>> or can I just send raw JTAG commands as the data payload?
>> ---Matthew Hicks
>> 
> No.
> 
> you can talk to almst any other interface but not to the xilinx
> platform cable as xilinx does not make the protocol info available.
> 
> so, in generic talking to JTAG from PC is piece of cake.
> but if the interface is xilinx platform usb, you just cant do it,
> unless you load 3rd party firmware into the cypress chip...
> Antti
> 

Matthew Hicks schrieb:
> Great. That sucks.  You'd think Xilinx would provide a way to send JTAG commands
> via iMPACT or maybe even Chipscope.  Guess not.
>
>
well, they "kinda" do...
in such manner that I never bothered even trying..

1 you can execute SVF or maybe even STAPL with impact
2 you can send commands in impact debug mode
3 you can start chipscope and use tcl to send commands
4 you can RE the tcpip protocol and send commands to impact cable
server
5 you can RE the chipscope server protocol and send commands to
chipscope server

all those methods work...

but you cant talk to platform USB cable, unless you use your own
firmware replacement
or RE the usb protocol or DLL entry poins to xilinx libraries :(



Antti