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Sayali's avatar
Sayali
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6 months ago

Error: can't access JTAG chain

I am using MAX V 5M160ZE64I5N programmable device.

While I am trying to connect custom PCB board having the programmable device using USB blaster for JTAG communication, the following errors are observed:

Error: can't access JTAG chain

Error: operation failed

Also, the TDI, TMS, TCK signals are observed to be Ok while there is a issue with TDO signal. If TDO is pulled up to +3.3V through resistor (10K-ohm) it will stuck at high state only and same goes with pull down, it will stuck at 0V.

TDI & TMS pulled up to +3.3V through 10K-Ohm resistor. TCK pulled down to gnd through 10K-Ohm.

VCCIO = +3.3V

VCCINT = 1.8V

Software Version: Quartus prime 22.1std

Windows : Windows 11 pro

Also, tried to check connection through NIOS V command shell. Please find the attached snapshot indicating " unable to read device chain - JTAG chain broken".

Although, the Intel EPM240 development board having MAX II can get connect successfully using the same USB blaster (terasic).

Kindly suggest a possible solution to the problem.

Thank you!

4 Replies

  • FvM's avatar
    FvM
    Icon for Super Contributor rankSuper Contributor
    Hi,
    TDO is tri-stated unless a valid JTAG command producing output is received. In so far the observation suggests incorrect connection of TCK, TMS or TDI. Or missing MAX V power supply.
  • Sayali's avatar
    Sayali
    Icon for New Contributor rankNew Contributor

    The signals TDI, TMS, TCK, TDO from USB blaster to our custom PCB board is connected as shown in the connection image attached.

    Also, attaching the image indicating placement of pull up, pull down resistors on PCB board.

    Further images indicates all signals observed on oscilloscope.

  • FvM's avatar
    FvM
    Icon for Super Contributor rankSuper Contributor

    Hi,
    looks like only TCK has full signal swing, TDI and TMS apparently haven't.

  • Sayali's avatar
    Sayali
    Icon for New Contributor rankNew Contributor

    The issue is resolved, it was due to some soldering issue with CPLD.