I'm still here,sorry if i post the same message 2 times,but really i'm spending lot of hours daily trying to solve this problem
my self-built a cable III works fine with cpld's like xc95144xl(3,3V),i can recognize it ,readback,erase,blank check and write. Then i dared to connect it with a (scraped as ever) fpga,a virtex xcv200e but the boundary scan chain does not see it at all.Plugging the cable III in the cpld it still works fine
what i did was this :
i built a level shifter for the TDO,because the cable is not expected to work with such low levels,this 2 bjt level shifter works fine even with a 4 mhz square wave,and i think this is faster than any signal could ever move through the parallel port(is it true?)
i connected just one 1.8V supply to the VCCINT of the fpga(pin A9),it is not easy to test it (soldering wires on a bga as i do is even worse ...)but it looks that it should be enough for the core,correct???or i need to
i connected in 7 points the 3.3VCCO(A2,B2,B12 , A13,G12,N1,M2) and the ground in 3 points(A1,J1,N12)
i connected the jtag signals,TCK,TDI,TMS,TDO(this one to the level amplifier)
I connected PROGRAM fixed to 3.3V,then i tried to connect it with TMS,same result.....
I left M0 and M2 open,and them are high,M1 tied to ground,this for choosing boundary scan mode
using the debug chain utility i verified that the signals are working but i noticed that there is no movement on TMS,and of course on TDO
there is something else missing?
Thank you to everyone in the group that will help me or just will read this
Diego