IMX6Q

[vittoria98]

Hello, in trying to test a board usign XJTAG link2. The board has an IMX6Q. I've checked the pin mapping and reset sequence but when I try to check the chain, it shows the same error: 

No valid data returned from the JTAG chain.
Perhaps the pin map is incorrect, or the board is not powered.

Check Chain failed

How can I fix this error?

[riteshmpatel]

Hi @vittoria98,

I hope you are doing well.

One can refer to Example 3: No Valid Data Returned from the below link to know the possible causes of the error:

https://www.xjtag.com/support/application-notes/jtag-chain-debugging/

In addition to the above, could you please also check what is the status of the JTAG reset pin?

Thanks & Regards,
Ritesh M Patel

[vittoria98]

Hi @riteshmpatel thank you for your answer, 

I've already checked the status of the JTAG reset pin and it should be alright, and also I've set the reset sequence. 

Do you have any other suggestion?

[riteshmpatel]

Hi @vittoria98,

You may refer to the below link which describes the different errors faced by JTAG.

https://www.xjtag.com/support/application-notes/jtag-chain-debugging/

Thanks & Regards,
Ritesh M Patel

[vittoria98]

Hi @riteshmpatel, I still have the same error... 

How can I be sure that the test reset sequence I'm using is the right one? 

Thank you, 

Vittoria

[riteshmpatel]

Hi @vittoria98,

Apologies for the delay in response.

1. For the JTAG Connection/Test sequence

Please try the JTAG Connection with i.MX6 reference board (e.g. SARBE SD Board) to make sure the JTAG Tool and Test sequence are correct.

2. For the RESET sequence

Please make sure the RESET signal from JTAG Tool (XJTAG link2) can drive the i.MX6 POR_B to low to reset the system.

3. For the JTAG Bus connection

Sometimes the longer trace design (e.g. place the JTAG interface on debug board) may impact to the JTAG connection, and a jumper wire to shorten the trace length (connect the JTAG connector to the CPU board directly) can solve it.

Thanks & Regards,
Ritesh M Patel

[vittoria98]

Hello @riteshmpatel thanks for the reply, 

How do I check if the RESET signal from JTAG Tool (XJTAG link2) can drive the i.MX6 POR_B to low to reset the system?

Thank you, 

Vittoria

[riteshmpatel]

Hi @vittoria98,

You can use Oscilloscope to monitor the RESET signal from JTAG Tool (XJTAG link2) and i.MX6 POR_B signal to check the RESET flow.

Thanks & Regards,
Ritesh M Patel