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Altera_Forum's avatar
Altera_Forum
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17 years ago

JTAG pin 6

Hi, I design a board with cyclone II. I employ JTAG for configuration, signaltap ... My question is : What does pin n°6 of jtag be connected to ? In Cyclone handbook, it is just a n...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

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I have burnt 2 USB Blaster (same symptoms) with card in which JTAG pin 4 and 6are connected to VCC

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The pin 6 connection involves an additional risk when connecting or disconnecting the USB interface while the USB Blaster is powered by the target board, because the JTAG drivers apparently aren't hot-plug proof. I didn't consider this problem in my above statement.

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JTAG 4 goes to VCCA or VccIO through 1 kOhm

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No it's usually connected without a series resistor. Because the pin supplies the JTAG drivers in the USB Blaster, a series resistor must be at least low resistance to allow USB Blaster operation.