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AR# 1215

dup to xapp017

Description

Keywords: bscan, boundary scan, jtag, xc4000, xc5200

Urgency: Standard

General Description:
When are the Boundary Scan instructions available in the XC4K/XC5K/Spartan devices?

Solution

Boundary scan is available in the XC4000 family and the XC5200 family devices before, during, and after configuration. However, different functions are available at each stage.

If you want to use boundary scan after configuration, then you must place the BSCAN symbol and TAP pins in the schematic, or instantiate the BSCAN symbol and the TAP pins in the HDL code.

If you are only interested in using Boundary Scan before the FPGA is configured, then you do not need to put the BSCAN symbol and TAP pins in the design at all, but configuration must be delayed by holding the /INIT pin Low.

If the design has already been compiled, Boundary Scan can be turned on via XDE or EPIC. Refer to (Xilinx Answer 1220) for more details.

The configuration section of the data book has a flow chart describing the configuration sequence. It lists which JTAG functions are available during each stage of configuration. Xilinx recommends that you not use Boundary Scan while the device is configuring.
AR# 1215
Date Created 08/31/2007
Last Updated 09/30/2005
Status Archive
Type ??????