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Altera_Forum
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15 years ago

Byte Blaster MV cable Length

Hello, I have ByteBlaster MV from Altera,Its not working.The error in quartus is " Unable to Scan the chain" I suspect the problem is in JTAG FRC Cable(10 pin). Can any one tell that what is th...
Altera_Forum's avatar
Altera_Forum
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15 years ago

Before running the JTAG with the long cable for a long time (30 minutes), I would check with a scope to see what your signal looks like. If it is overshooting into the 5V range, you will end up damaging the FPGA.

On the blaster side, you will need to have series resistors on TDO (blaster to board), TMS, and TCK. I would start with 33 ohm.

Of course all of this depends on the type of cable used and the length. I am not sure how you have your 100 ohms connected on the board side. Are they in series? How are they connected?

Having series resistors on TDO (Blaster to Board), TMS, and TCK at the board side, will not help your signal issues. Having a series resistor on TDO (board to blaster) at the board side will reduce over/undershoot seen at the blaster.