We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 24699

9.1.01i ChipScope Pro - When issuing Shift-DR instruction with TCL JTAG, bad data is returned


If TCL JTAG is used to issue a Shift-DR instruction in read-only mode and in addition if TDI is set to '1', invalid data is returned. This occurs only when using a Platform USB Cable.


Using Shift-DR in read-only mode and setting TDI to 1 will use fast read, and there is a problem with the way in which fast read is implemented. There are two alternatives to using read-only and setting TDI to 1.  


1. If TDI does not matter when shifting out bits, then set TDI to 0.  

2. Alternatively, just use read/write mode and make TDI a buffer filled with constant 0's or constant 1's.  


This will be fixed in ChipScope 9.1.02i.

AR# 24699
Date Created 09/04/2007
Last Updated 05/21/2014
Status Archive
Type General Article