Answers Database
JTAG - When is Boundary Scan available for use in the XC4000 based families?
Record #1215
Problem Title:
JTAG - When is Boundary Scan available for use in the XC4000 based families?
Problem Description:
Urgency: Standard
General Description:
When are the Boundary Scan instructions available in the XC4K/XC5K/Spartan devices?
Solution 1:
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 the user wants to use boundary scan after configuration, then the
user must place the BSCAN symbol and TAP pins in his schematic, or instantiate
the BSCAN symbol and the TAP pins in the HDL code.
If the user is only interested in using Boundary Scan before the
FPGA is configured, then the user doesn't need to put the BSCAN symbol
and TAP pins in his 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 http://www.xilinx.com/techdocs/1220.htm for details
on this.
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. It reccomended to not use Boundary Scan while the device
is configuring
End of Record #1215 - Last Modified: 01/10/00 21:38 |
