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AR# 47000

ChipScope - "ERROR: Internal Error: Failed reading JTAG Instruction Register." occurs when there is a non-Xilinx device in the chain


The following errors occur when connecting to the JTAG cable in the ChipScope tool:

ERROR: Internal Error: Failed reading JTAG Instruction Register.
ERROR - Device 0: Communication failed with device: 0


This issue is usually related to the IR length defined for non-Xilinx devices; if this is incorrect, it can prevent the IDCODE of the devices in the chain being read out incorrectly which causes problems when attempting to initialize the chain.

If this error occurs, ensure that the IR length that is being added is correct based on the BSDL file of the non-Xilinx device.

AR# 47000
Date Created 03/27/2012
Last Updated 05/15/2013
Status Active
Type General Article
  • ChipScope Pro - 13.4