JTAG detection failed for i.mx8mplus

[Bhardwaj]

We have been working on i.mx8mplus EVK while debugging getting an failed to connect to the target error. while debugging we observed on each and every pin of JTAG in oscilloscope then we found that TDO pin is 0.5v continuously. Do this create any issue?

             IDLE                   Debugging

-----------------------------------------------

VTRF: 1.8V(high)              1.8V(high)

TMS: 0V(low)                  high low(changing)

TCK: 0V(low)                  depends on CLK values

TDI: 1.8V(high)                data

TDO: 0.5V                        0.5V

Reset: 1.8V(high)           1.8V(high)

[Manuel_Salas]

Hello @Bhardwaj 

I hope you are doing very well.

Yes, the TDO signal must be aligned to the VTref ≈ 1.8 V.

Which debugger are you using?

According to the reference manual, the recommended procedure to start the JTAG controller is:

Also, you can try to follow the AN14367 (Debugging Cortex-A U-Boot and Native RTOS on i.MX 8M Plus and i.MX 93 EVKs).

Best regards,

Salas.

[Bhardwaj]

Hi salas,

We are using Dstream-st debugger. We are doing the procedure mentioned in document. I have a doubt that

does the cortex-a53 can be detected after boot or not using jtag?

If not, can i know the procedure how the processor boot flow and when should i connect to target through jtag?