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Altera_Forum's avatar
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
Icon for Honored Contributor rankHonored Contributor
14 years ago

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For the resistor I may use a 22ohm resistor, as I have one already in my design, but what would be the effect on the TCK line, if the resistance is not right, because I dont want to have to rework the PCB once it is made.

I will only be using the one FPGA device in my design.

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22-Ohms will be fine.

The key thing is that you have a resistor footprint on the PCB. That way if you do see ringing on the TCK line, you can adjust its value without a re-spin of the PCB.

Cheers,

Dave