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Altera_Forum
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15 years ago

Quartus II (v10.0) + Cyclone II : JTAG Issues

Dear all, I have a JTAG chain of two devices. The first is a TI processor and the second a Cyclone II FPGA. Using the TI JTAG emulator and configuring it to 'bypass' the cyclone II with ...
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Altera_Forum
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15 years ago

We have replaced the yellow USB Blaster flat cable (regardless if Rev B or C) by a simple ribbon cable of max. 10cm as we had some JTAG problems in the past on boards with more than 1 device on the chain.

If you have seen improvements by using a different connection as the flat cable you should inspect your jtag signals how they are layoutet and if you have the correct pull up's and down' and the correct voltage for pull up's. out of my head 3,3v for C2 and 2,5V for C3

could you show a schematic that just shows the jtag connector and all connections / parts involved to see the signal flow and how all jtag signals are connected ?

do you have any else like the JTAG USB Blaster that is used for production inviroment to scan the jtag line ?