Error JTAG chain problem detected

[majsta]

My design worked for about 3 hours and now gives me this error. I jus
can't understand what is wrong with it now. I didn't do anything wrong.

!Error: JTAG chain problem detected
!Error: The TDI connection to the first detected device EP2C8 might b
shorted to VCC or is an open circuit
!Error: The TCK and TMS connections to the device before the first detecte
device EP2C8 might have a problem
!Info: Detected 1 device(s)
!Info: Device 1: EP2C8

device is EP2C8Q208C8

TDI pulled high with 10Kohm resistor also TMS
TCK pulled down with same resistor value
Pin 2 on JTAG header connected to GND
Pins 4 and 6 connected to VCC 3.3V
Pin 10 connected to GND
TDO connected directly to cyclone II
MSEL 0 and 1 to GND
nCE to GND
also on board is used EPCS4SI8 but I disconnect that one but proble
remains.

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[Jack Leong]

On Mar 5, 6:16 pm, "majsta"
<imajstorovic@n_o_s_p_a_m.n_o_s_p_a_m.yahoo.com> wrote:

My design worked for about 3 hours and now gives me this error. I just
can't understand what is wrong with it now. I didn't do anything wrong.

!Error: JTAG chain problem detected
!Error: The TDI connection to the first detected device EP2C8 might be
shorted to VCC or is an open circuit
!Error: The TCK and TMS connections to the device before the first detected
device EP2C8 might have a problem
!Info: Detected 1 device(s)
!Info: Device 1: EP2C8

device is EP2C8Q208C8

TDI pulled high with 10Kohm resistor also TMS
TCK pulled down with same resistor value
Pin 2 on JTAG header connected to GND
Pins 4 and 6 connected to VCC 3.3V
Pin 10 connected to GND
TDO connected directly to cyclone II
MSEL 0 and 1 to GND
nCE to GND
also on board is used EPCS4SI8 but I disconnect that one but problem
remains.

---------------------------------------
Posted throughhttp://www.FPGARelated.com

sometimes altera jtag programmer is easily affected by some signal
integrity issues on the jtag chain for some reason i don't know. try
turning off the board and disconnect the jtag programmer (whatever
blaster) from the computer and then u power on the board and connect
the blaster to cpu and try again.

 

[majsta]

Ok thank you, but here is some info after investigation. Two reasons firs
one is regarding to pin 6 on JTAG and for ByteBlaster it needs VC
connection but in USB blaster stays NC. Second one may be with AnalogGN
and DigitalGND problems on the board, and after solving those two thing
problem is gone

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