problem with usb emulator

hello everybody,

ours is an audio related product which contains 3 c672x dsps connected in daisy chain.
we are debugging with engineering prototype.
am facing a strange problem.c672x dsp works fine(load and run) with PP+ emulator.
but doesnt work with usb emulator.

1. Found that the dsp board gets connected and works well with PP+ emulator.
with with usb emulator, even we were not able to get connected.

2. after investigating found that system power supply was culprit.now we are
providing separate power supply to dsp board.

3. now the new problem is

when we use PP+ emulator all the three dsps works fine.but if we use
usb emulator only the middle dsp is not working other two 1st and 3rd are working
good.not working means we can connect to dsp using ccs, can download program but if
we run then no output is observed.we have designed the jtag circuit according to ti
application notes.power supply is fine. dsp power is fine.it is not software problem as
it works good(can get audio o/p) with PP+, EMU0/1 are high, tck clock is fine,believe
tdi/tdo is fine as sdconfig test passes.

please let me know is there anything else to be checked.

PS: we never faced this problem in design prototype. there both PP+ and usb are working good.

regards
abbi

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Prabhu-
> ours is an audio related product which contains 3 c672x dsps connected in daisy
> chain.
> we are debugging with engineering prototype.am facing a strange problem.c672x dsp
> works fine(load and run) with PP+ emulator.
> but doesnt work with usb emulator. 1. Found that the dsp board gets connected and
> works well with PP+ emulator.
> with with usb emulator, even we were not able to get connected. 2. after
> investigating found that system power supply was culprit.now we are
> providing separate power supply to dsp board. 3. now the new problem is when we
> use PP+ emulator all the three dsps works fine.but if we use
> usb emulator only the middle dsp is not working other two 1st and 3rd are working
> good.not working means we can connect to dsp using ccs, can download program but
> if
> we run then no output is observed.we have designed the jtag circuit according to
> ti
> application notes.power supply is fine. dsp power is fine.it is not software
> problem as
> it works good(can get audio o/p) with PP+, EMU0/1 are high, tck clock is
> fine,believe
> tdi/tdo is fine as sdconfig test passes. please let me know is there anything else
> to be checked. PS: we never faced this problem in design prototype. there both PP+
> and usb are working good.

1) Which emulator? Some vendors have known issues with USB vs. parallel port
versions, or vice versa.

2) This is likely a signal integrity issue:

-suggest to check TCK in particular to make sure it's rise-time
is sharp with no noise that could lead to glitches or possible
double-clocking on the second DSP

-how long is the TDI-TDO data path? If this becomes several cm
due to multiple devices, that could be a problem

-where do you pick off TCK_RET signal? If you're doing this
at the JTAG header, you should try getting it from the
furthest of the 3 DSPs away from the header

3) SDConfig test is not enough. Suggest to try xdsprobe.exe for more rigorous test
of scan path.

-Jeff Start a New Thread