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Altera_Forum
Honored Contributor I
1,078 Views

JTAG contacts problem

Good afternoon, members of the forum. 

I have a used card with a Stratix V chip. For a long time I could not get connected by jtag. 

 

I decided to use a multimeter to measure the contacts from the JTAG connector to the chip. And found that the leg of the chip TDI is connected to the 3-pin connector (TDO) 

And leg of the chip TDO is connected to the 9-pin connector (TDI) 

 

Tell me please, is it possible that the previous owner in some way changed the purpose of the legs through the firmware? 

 

 

Thank you in advance
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5 Replies
Altera_Forum
Honored Contributor I
48 Views

Hi, 

 

Not possible through firmware because it is having dedicated pins & function.It can be only done through hardware design. 

 

For correcting it you required hardware change. 

You can design a adapter with help of dot-matrix board and BergStik connectors with stack-up arrangements and use. 

 

Best Regards, 

Anand Raj Shankar 

(This message was posted on behalf of Intel Corporation)
Altera_Forum
Honored Contributor I
48 Views

 

--- Quote Start ---  

Hi, 

 

Not possible through firmware because it is having dedicated pins & function.It can be only done through hardware design. 

 

For correcting it you required hardware change. 

You can design a adapter with help of dot-matrix board and BergStik connectors with stack-up arrangements and use. 

 

Best Regards, 

Anand Raj Shankar 

(This message was posted on behalf of Intel Corporation) 

--- Quote End ---  

 

 

Thanks. 

I decided to download the bsdl file from the alteras site, replace there two contacts in places and try running jtag scanning. In a few hours I'll try
Altera_Forum
Honored Contributor I
48 Views

Hi, 

 

How BSDL will help in this case, can you help me in understanding? 

You need to go with hardware changes only. 

or 

If you are ready to do some experiments than, You can try to modify pin assignments in USB Blaster in firmware, If you get that program for you max device. 

Not Recommended
Altera_Forum
Honored Contributor I
48 Views

 

--- Quote Start ---  

Hi, 

 

How BSDL will help in this case, can you help me in understanding? 

You need to go with hardware changes only. 

or 

If you are ready to do some experiments than, You can try to modify pin assignments in USB Blaster in firmware, If you get that program for you max device. 

Not Recommended 

--- Quote End ---  

 

 

Thank you so much. It turns out I did not correctly check. 

Now I checked all the contacts and the circuit was assembled correctly. But now the values of the resistors in the diagram show not the naminal - red and blue values. 

 

 

 

 

Resistors are definitely worth the new ones, even if you remove the resistors, the circuit still shows such values. Do you think the chip itself?
Altera_Forum
Honored Contributor I
48 Views

Presuming you have checked correct function of your USB Blaster by using it with a different board, I see two possible reasons for JTAG failure 

- FPGA is held in POR due to missing or to too low supply voltage for one of the monitored nodes 

- FPGA JTAG interface has been damaged  

 

JTAG pull-up and pull-down resistor can be varied in certain range without affecting correct operation.
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