Answers Database

BOUNDARY SCAN/JTAG: Pullup/Pulldown Availability in 5k TDO


Record #1359

Product Family:  Hardware

Product Line:  5200

Problem Title:
BOUNDARY SCAN/JTAG: Pullup/Pulldown Availability in 5k TDO


Problem Description:
Keywords: xc5200, 5k, bscan, tdo, pullup, pulldown, xde, epic

Urgency: standard

General Description:

After a 5k device is configured, and if boundary scan is not
enabled, then the TDO pin can be used as an output or obuft.

How to access the pullup/pulldown on the TDO pin?


Solution 1:

To use the pullup/pulldown in the TDO pin for a output, or obuft,
the user must draw it in his/her schematic, or instantiate the
pullup/pulldown and TDO pad in his/her HDL code.



Solution 2:

Load the .lca file into XDE.

Find out which pad location corresponds to the TDO pin from the
data book depending upon your package.

Run the command 'editblk' on that particular IOB that is the TDO
pin for the given 5k device.

When you execute 'editblk', XDE will let you select either a
pullup, a pulldown, or no pullup/pulldown for the TDO pin, if
bscan is not enabled after the FPGA is configured.



Solution 3:

Load the .ncd file into EPIC.

Find out which pad location corresponds to the TDO pin from the
data book depending upon your package.

Find the PAD in EPIC using the 'find' command. Use 'Site' as
the criterion. Select the PAD and use Edit->Add to add the PAD
to the database. Select it again and run the 'Editblock'
command.

When you execute 'editblock', EPIC will let you select either a
pullup, a pulldown, or no pullup/pulldown for the TDO pin, if
bscan is not enabled after the FPGA is configured.



End of Record #1359