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AR# 143

*Obsolete* JTAG - What is the state of the INIT pin during boundary scan configuration?


Keywords: xc4000, xc5200, Spartan, init, configure, low, JTAG

Urgency: Standard

General Description:
The state of the /INIT pin on a XC4000 family device and its derivatives during configuration using Boundary Scan.


In order to configure the XC4000, XC5200, and Spartan devices using boundary scan, the /INIT pin should be held low until the CONFIGURE instruction has been executed.

If INIT is not held low, the device may assume standard configuration, sample the mode lines, and disable the JTAG Boundary scan architecture.

Additionally, momentary glitches on the INIT pin may cause the device to be thrown out of boundary scan mode, or to give nonsensical scan outputs.

AR# 143
Date Created 08/31/2007
Last Updated 09/26/2005
Status Archive