Xilinx UG078 manual JTAG Chain, JTAG Termination Jumper, Detailed Description

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Detailed Description

4. JTAG Chain

Jumper J17 provides the ability to have the Virtex-4 in the JTAG chain or remove it from the JTAG chain.

Note: The Virtex-4 device must not be in the socket when detecting the ISPROM in the chain.

5. JTAG Termination Jumper

The DUT TDO pin can be jumpered to the TDO TERM pin or the downstream TDO pin. When another board is connected to the downstream System ACE connector or downstream interface connector, jumper the DUT TDO pin to the downstream TDO pin for serial chaining. The connection allows the DUT TDO pin to be connected to the next device in the chain.

The TCK and TMS pins are parallel feedthrough connections from the upstream

System ACE interface connector to the downstream System ACE interface connector and drive the TCK and TMS pins of the onboard PROM and the DUT.

Note: The termination jumper must be in place on the last board in the chain to connect the TDO pin of the final device to the TDO feedback chain.

Virtex-4 LX/SX Prototype Platform www.xilinx.com 13

UG078 (v1.2) May 24, 2006