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Altera_Forum
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14 years ago

JTAG interface

Hello, I would like to interface Cyclone IV JTAG interface via both ways : 1. JTAG USB blaster. 2. FTDI FT2232 MPSSE interface. I am using VCCIO 3.3V in Jtag bank and in figure 8-23 in c...
Altera_Forum's avatar
Altera_Forum
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14 years ago

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So with the pin 8 line being left floating on the board and with appropriate buffering and pulling TDO line high with say a 10K resistor I should have a working programming interface between FPGA and USB-Blaster?

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Yes.

If you are going to the trouble of buffering the inputs, then also buffer the TDO output, or at least put a 100-ohm series resistor in the path to provide some form of ESD protection (the TDO trace would go from the FPGA, to the pull-up, then through the series resistor to the JTAG connector).

Why go to this trouble? Well, the JTAG connector is the one place a user can get their electrostatically charged fingers!

Cheers,

Dave