Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

External JTAG port on DK-DSP-3C120 - EthernetBlaster

Hi All,

Has anyone used the external JTAG port on the Cyclone III dev kit?

I've tried an EthernetBlaster and USB-Blaster using Number 4 in Table 2-7 of the CIII Dev kit Reference Manual (i.e. switches and jumpering).

Programming is unreliable (has never completed) and according to the JTAG Diagnostics in the Quartus II Programmer, the JTAG is inconsistent (i.e. unreliable).

Selecting the MAX II on the board (Number 5 in the above table, works perfectly.

Internal USB blaster works fine, but I want to be able to use the EthernetBlaster.

Have tested on 2 dev kits with the same results.

Any thoughts??

Robert.

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Although I haven't tried that particular dev kit, I know from various other boards and dev kits that I have worked with is the USB blaster may have issues if there are reflections on the TCK line.

    For improved reliability we've modified our USB blasters by replacing the 10 ohm source termination resistor with a 22 ohm resistor. So far it's helped in all cases where we had issues, and hasn't hindered in any case where we did not have any issue previously to the modification.

    Pete
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Hi All,

    Some follow-up (for a change!!).

    There seems to be a coupling issue between the JTAG port and the HSMC D/A & A/D card that comes with this kit, but ONLY when that HSMC card is connected to HSMC Port A. Interestingly, this HSMC card does not appear to use the JTAG (according to the schematics), but the HSMC ports do have pins for JTAG. No problem found when using HSMC Port B, or any other HSMC card I have connected to Port A (Debug header, termination header, Nial's Stewart's General Purpose Interface Board V2.0).

    Altera have been able to repeat the problem with the EthernetBlaster and USB-Blaster. A work-around I've found is to make a very short (50mm) 10 way IDC ribbon cable, in place of the original 200mm flex PCB.

    Regards,

    Robert.