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How to test the JTAG in my new design?

Question asked by HelloTom on May 9, 2010
Latest reply on May 10, 2010 by HelloTom

Hi, everyone.

    I have design my own system use BF561. My soft environment is visual dsp4.5.  the emulator is HPUSB. it works well when I program on BF533 ez-kit lite .

   But , when I connect the emulator header to my own system . And open the visual dsp 4.5. It cannot find my target.  it says "visual dsp has  detect 0 device int the jtag chain ".

   I am sure the crystal works well, the frequency is 20MHz. the VDD_INT is 1.22V and  VDD_EXT is 3.3V. Then, I use oscilloscope to find the problem.

the following is the signal on JTAG interface:

when I connect the target from visual dsp4.5.

TCK pin has a series of  '0' and '1'  . I mean the pin has clock signals for some time.


EMU   pin stay at '1' at last.


TMS   pin has a rectangle pulse "1" and then come to ' 0 '.      ____|         |______


TRST   pin is '1'  at last.

TDI      pin is pull to high for some time and then come to  '0'  at last. I do not think it is data which contains '0' and '1'.

TDO    pin do not change at all.



I cannot judge what is the problem.

may be the BGA pins are not solder well?  I am not sure.


WOULD YOU PLEASE TELL ME HOW TO FIND THE CAUSE which makes visual dsp4.5 find no target?

thanks a lot!