Custom board issue

I am not familar with those devices, but you might want to take a look the "Tips" section at .

Stephen

I realized that.  It might be the website has not been updated in a while.  here's the Tips I was referring to:

Tips

• Over 90% of scan related failures are a result of TCK/TCKRET signal.  Always check this signal first.  In many cases you may find that simply putting a scope probe on the TCK or TCKRET signal will make the diagnostics pass.  This is clear indicator that TCK/TCKRET signals needs to be cleaned up or filtered.  Testing has shown that on newer devices, DSP TCK is more noise sensitive then previous generations. Devices that fall into this class would be C64x, C55xx, OMAP, and custom ASIC devices.  The predominant cause is related to type of input buffer being used on these devices and other signal coupling both on the board and in the DSP or package.  In the majority of cases an AC terminator or small capacitor (12pf-33pf) at the DSP TCK pin will clear up the problem.  In other cases you may need to buffer the TCK/TCKRET signals and terminate to resolve the problem.
• The highest probability of emulator failure is the 14-pin JTAG connector.  This is especially true in production test and programming environments where JTAG cable may be inserted and removes hundreds of times a day.  If your 14-pin JTAG connector looks worn then run the diagnostics and twist/bend the JTAG cable near the connector.  The TMS and TRSTn signals are generally the first signals to fail as the JTAG cable is generally “peeled” off the target versus being removed in a straight upward fashion.
• If you are using a variable voltage emulator then first reset the emulator and probe the signals.  Be sure that the PD pin on the JTAG connector is at the proper voltage level.  Also, review the TCK/TCKRET for proper levels.  In many emulators the TMS and TRSTn pins will be high following an emulator reset check these pins also.
• Most emulator design guidelines are out of date with respect to newer DSP devices and TCK/TCKRET noise.  Routing a 4-6 inch TCK/TCKRET signals is not suggested for newer designs.  Instead this distance should be limited to no more then 2 inches and the provision for an AC terminator should be include as a safety precaution.  Also check with your emulator supplier to see if they have JTAG header adapters that include some form of buffering and termination. 
• Check with your silicon vendor as there may be known JTAG exceptions and special recommendations for the device you are using.

Do we need to set emulator port speed?  \if yes, what should we set?